Laser tissue interactions hold great promise in cancer treatment. Photothermal interaction aims at the direct cell destruction through the increase of local tissue temperature, while photochemical interaction aims at the cell destruction using free radicals produced through the activation of photosensitizers in the target tissue. Photobiological interaction can target the immune host system to induce long-term control. Photothermal and photochemical interactions can be significantly enhanced by photobiological interaction through the use of immunoadjuvants. In our experiments, three different immunoadjuvants, complete Freund’s adjuvant (CF), incomplete Freund’s adjuvant (IF), and c-parvum (CP), were used in the treatment of metastatic mammary tumors in conjunction with photothermal interaction. In addition, a specific adjuvant, Glycated chitosan (GC), has been used in combination with photodynamic therapy (PDT) in the treatment of mouse tumors. In the treatment of rat tumors, CF, IF and CP raised the cure-rates from 0% to 18%, 7% and 9%, respectively. In comparison, GC resulted in a 29% long-term survival. In the treatment of EMT6 mammary sarcoma in mice, GC of 0.5% and 1.5% concentrations increased the cure rates of Photofrin-based PDT treatment from 38% to 63% and 75%, respectively. In the treatment of Line 1 lung adenocarcinoma in mice, a 1.67% GC solution enabled a non-curative mTHPC-based PDT to cure a 37% of the tumor bearing mice.

Current limitation of both near-infrared (NIR) tumor imaging and photodynamic therapy (PDT) is their lack of sufficient tumor-to-tissue contrast due to the relatively non-specific nature of delivering dye to the tumor, which has led to false negatives for NIR imaging and inadequate therapeutic ratio for PDT. Hence, agents targeting “cancer signatures”, i.e. molecules that accumulate selectively in cancer cells, are particular attractive. One of these signatures is low-density-lipoprotein receptor (LDLR), which is overexpressed in many tumors. We have developed pyropheophorbide cholesterol oleate reconstituted LDL as a LDLR-targeting photosensitizer (PS) and demonstrated its LDLR-mediated uptake in vitro and in vivo. To improve the labeling efficiency for achieving high probe/protein ratio, tetra-t-butyl silicon phthalocyanine bearing two oleate moieties at its axial positions, (tBu)₄SiPcBOA, was designed and synthesized. This compound was designed to 1) prevent the PS aggregation; 2) improve the PS solubility in non-polar solvent; and 3) maximize the PS binding to LDL phospholipid monolayer. Using this novel strategy, (tBu)₄SiPcBOA was reconstituted into LDL (r-SiPcBOA-LDL) with a very high payload (500:1 molar ratio). In addition, (tBu)₄SiPcBOA reconstituted acetylated LDL (r-SiPcBOA)-AcLDL with similar payload was also prepared. Since Ac-LDL cannot bind to LDLR, (r-SiPcBOA)-AcLDL can serve as the negative control to evaluate LDLR targeting specificity. For biological evaluation of these new agents, confocal microscopy and in vitro PDT protocols were performed using LDLR-overexpressing human hepatoblastoma G2 (HepG2) tumor model. These studies suggest that LDL serves as a delivery vehicle to bring large amount of the NIR/PDT agents selectively to tumor cells overexpressing LDLR.

A new concept for photodynamic therapy (PDT) has been developed based on incorporating a photosensitizer (PS) and a singlet oxygen (¹O₂) quenching/scavenging molecule (Q) onto a disease-targeting carrier, such that the PS becomes activatable by light only when targeting has occurred. This has the potential to give very high disease specificity in PDT treatment. The first model compound designed using this concept was synthesized containing a pyropheophorbide as the PS and a carotenoid as the ¹O₂ quencher. These were kept in close proximity by the self-folding of a caspase-3 specific peptide sequence. Upon caspase-3-induced cleavage, the ¹O₂ production increase has been validated by direct ¹O₂ luminescence and lifetime measurements, providing proof-of-concept of this 'PDT beacon.'

Laser speckle contrast imaging (LSCI) is a noninvasive optical image technique that has been developed for imaging in vivo blood flow dynamics and vascular structure with high spatial and temporal resolution. It records the full-field spatio-temporal characteristics of microcirculation in real time without the need of laser beam flying. In this paper applications of this technique for monitoring changes of blood flow and vascular structure following photodynamic therapy (PDT) in vivo model were demonstrated. In this study, an in vivo model of chick chorioallantoic membrane (CAM) at embryo age (EA) of 10~13 days, was observed following PDT irradiated by a power tunable laser diode (λ = 656.5 nm). Laser intensity incident on the treatment site was maintained at 40 mW/cm² and photosensitizer of Pyropheophorbide Acid (Pyro-Acid) was used. CAM was adopted in PDT since it is a transparent in vivo model and the irradiated lights of laser can penetrate tumor with greater depth. The laser delivered through fiber bundle to the treatment site in PDT also acted as the coherent light source of LSCI. This study shows that LSCI can be used to assess the efficacy of peripheral vessels damage of tumor in PDT by monitoring changes of blood flow and vascular structure.

Early detection of the breast cancer is one of the keys to decrease the mortality of this disease. Now more and more attention is paid on development of non-invasive mammography. To study the feasibility of breast imaging with near infrared light, a frequency-domain optical scanner of breast cancer was designed and developed in our lab, based on the theory of interaction of Near Infrared (NIR) light and soft tissues. In this paper, the imaging prototype as well as the imaging processing system based on Matlab is described. The results of phantom experiments using the prototype of this scanner show a resolution in millimeter scale. The initial clinical trials show the feasibility of our prototype in clinical study. The prototype can scan a breast in 4 minutes. Images of the same breast obtained both with the prototype and with x-ray mammography are presented.

Thermotherapy could be selective to cure tumor because tumor is sensitive to temperature rise. The tumor blood flow rate, the average blood perfusion of tissue or temperature during heating was investigated respectively. However, thermal induced change in the vessel diameter of tumor was neglected. Especially, all of the above parameters were seldom measured at simultaneity. In this work, thermal induced effects on normal and tumor of mouse mesentery were investigated based on measuring microcirculation parameters and temperature. The dynamic blood flow rate was measured by the laser speckle microscopy, and the corresponding blood vessel diameter was recorded by the video camera, then the blood perfusion was deduced. Meanwhile, the temperature was recorded by high sensitively thermocouple. The results showed that the maximum change in diameter was larger than flow rate and blood perfusion for the both kinds of tissue under the same heating. Moreover, the maximum changes in vessel diameter, blood flow and perfusion in tumor are lower than those in normal during. The temperature rise in tumor changed more quickly than in normal tissue, and the critical temperature of thermal damage in the normal tissue was higher than the tumor. These measurements further proved that the tumor microcirculation was more sensitivity to heat than the normal tissue. This study is very important to know thermal induced affection from blood perfusion of micro vessel net both in tumor and normal tissue. It will help to explore thermotherapy mechanism and evaluate the thermotherapy effect, ascertain thermal dose, and select appropriate Rx.

In order to develop a novel diagnostic technique, as an adjunct modality to SDT, that uses the gallium-porphyrin derivative ATX-70 as a sonosensitiser mediated by a chemiluminescent probe to produce sonochemiluminescence (SCL) for imaging and localization of cancer within tissue in vivo. The fluoresceinyl Cyprodina luminescent analogue (FCLA) was used as an optical reporter for singlet oxygen generated from the sonosensitisation reaction of ATX-70 in the model solutions and in the in vivo nude mice bearing mammary cancer. The sonosensitized chemiluminescence from the reaction of FCLA with ¹O₂ was detected by a highly sensitive light-detector. The effect of FCLA with different doses on cell viability was also assessed with MTT assay. The results showed with the FCLA as the reporter, there is clear evidence that the aqueous solution of ATX-70 exposed to ultrasound forms ¹O₂ in the system. In the in vivo experiments, the tumor-bearing mice are imaged with a great contrast during sonosensitization of ATX-70 mixed with FCLA as the SCL probe. No significant cytotoxity was detected at the different FCLA doses. The results indicated that a novel cancer imaging method, named as the sonodynamic diagnosis (SDD), can be established by the sonodynamic action with the assistance of SCL probe. Therefore, this technique could have potential applications in the clinical diagnosis of cancer diseases at an early stage, and can be used to assess the treatment efficacy during the sonodynamic therapy of cancers.

In this pre-clinical study, photodynamic therapy (PDT) mediated with a vascular acting photosensitizer Tookad (palladium-bacteriopheophorbide) is investigated as an alternative treatment modality for the ablation of prostate cancer. Canine prostate was used as the animal model. PDT was performed by interstitially irradiating the surgically exposed prostates with a diode laser (763 nm) to activate the IV infused photosensitizer. The effects of drug dose, drug-light interval, and light fluence rate on PDT efficacy were evaluated. The prostates and adjacent tissues were harvested at one-week post PDT and subjected to histopathological examination. The dogs recovered well with little or no urethral complications. Urinalysis showed trace blood. Histological examination showed minimal damage to the prostatic urethra. These indicated that the urethra was well preserved. PDT induced prostate lesions were characterized by marked hemorrhagic necrosis with a clear demarcation. Maximum lesion volume of ~3 cm³ could be achieved with a single 1-cm diffuser fiber at a dose level of 1 mg/kg and 200 J/cm, suggesting the therapy is very effective in ablating prostatic tissue. PDT induced lesion could reach the capsule layers but adjacent tissues were well preserved. The novel photosensitizer is a vascular drug and cleared rapidly from the circulation. Light irradiation can be performed during drug infusion thereby eliminating waiting time. The novel vascular acting photosensitizer Tookad-mediated PDT could provide an effective alternative to treat prostate cancer.

Cortical spreading depression (CSD) has been known to play an important role in the mechanism of migraine, stroke and brain injure. Optical imaging of intrinsic signals has been shown a powerful method for characterizing the spatial and temporal pattern of the propagation of CSD. However, the possible physiological mechanisms underlying the intrinsic optical signal (IOS) during CSD still remain incompletely understood. In this study, a spectroscopic recording of the change in optical intrinsic signal during CSD was performed and an analysis method based on the modified Beer-Lambert law was used to estimate the changes in the concentration of HbO₂ and Hb, and changes in light scattering from the spectra data. The CSD were induced by pinprick in 10 α-chloralose/urethane anesthetized Sprague-Dawley rats. In all experiments, four-phasic changes in optical reflectance were observed at 450 nm ~ 570 nm, and triphasic changes in optical reflectance were observed in the range of 570 nm ~750 nm. But at 750 nm ~ 850 nm, only biphasic changes of optical signal were detected. Converting the spectra data to the changes in light scattering and concentration of Hb and HbO₂, we found that the CSD induced an initial increase in concentration of HbO₂ (amplitude: 9.0±3.7%), which was 26.2±18.6 s earlier than the onset of increase of Hb concentration. Furthermore, the concentration of HbO₂ showed a four-phasic change, whereas the concentration of Hb only showed a biphasic change. For the changes in light scattering during CSD, a triphasic change was observed.

A novel three-dimensional human head modeling method on laser technology, using the CCD camera to receive the scanning information, based on the theory of aerial photography surveying, is reported here. We introduce the mode integration of human head, its mathematical model and the principle of human head feature identifying. The laser scanning human head three-dimensional modeling system is established.

Several clinical psoriasis lesion groups are been studied for digital RGB color features extraction. Previous works have used samples size that included all the outliers lying beyond the standard deviation factors from the peak histograms. This paper described the statistical performances of the RGB model with and without removing these outliers. Plaque lesion is experimented with other types of psoriasis. The statistical tests are compared with respect to three samples size; the original 90 samples, the first size reduction by removing outliers from 2 standard deviation distances (2SD) and the second size reduction by removing outliers from 1 standard deviation distance (1SD). Quantification of data images through the normal/direct and differential of the conventional reflectance method is considered. Results performances are concluded by observing the error plots with 95% confidence interval and findings of the inference T-tests applied. The statistical tests outcomes have shown that B component for conventional differential method can be used to distinctively classify plaque from the other psoriasis groups in consistent with the error plots finding with an improvement in p-value greater than 0.5.

Optoacoustic tomography, which maps the distribution of the optical absorption within biological tissues by use of time-resolved laser-induced ultrasonic signals, is attracting increasing interests in biomedical imaging. As a hybrid imaging technique, it takes the advantages of both optical and ultrasonic techniques in that the tomography image has the optical contrast similar to the optical techniques while enjoying the high spatial resolution comparable to the ultrasound. In theories, this technique can image the objects embedded several centimeters deep within targets with a resolution of several tens of microns. In this paper, the current-state-of-the-art time-resolved optoacoustic tomography in biomedical imaging is reviewed. This paper consists of four sections: principles of optoacoustic tomography, signal acquisition and process, recent progress and advance, and problems and outlooks for the technique.

A non-invasive method to determine the optical property of biological tissue by the combination with ultrasound modulation and diffuse reflection light is firstly presented. A focused ultrasound beam through tissue has the modulated diffuse light located within the focal spot and so that the diffuse fluence distribution is easily detected from out of tissue. Based on the diffuse reflectance fitted formula concluded from Monte Carlo simulation by authors, the optical property including absorption coefficient, scattering coefficient, average scattering cosine, and even the refractive index can be rebuild. In addition, this new method is very significant to measure a light dose in vivo in laser medicine and surgery.

A real-time photoacoustic (PA) imaging system based on multi-element linear transducer array was developed and test on phantoms. A Q switched Nd:YAG laser operating at 532 nm and 20Hz repeat rate was used in our experiment as thermal source. The multi-element linear transducer array consists of 320 elements. By phase-controlled method, 64 signals, one of which gathered by 11-group element, make up of an image. It was acquired in only about 3 seconds. Phantom experiment results can map the distribution of the optical absorption correctly. Compared to other existing technology and algorithm, the PA imaging based on transducer array was characterize by speediness and convenience. It can provide a new approach for tissue functional imaging in vivo, and may have potentials in developing into an appliance for clinic diagnosis.

The method is based on chromatic visual evoked potential (VEP) measurement. The equiluminance of color stimulus in normal subjects is characterized by L-cone and M-cone activation in retina. For the deuteranopes and protanopes, only the activations of one relevant remaining cone type should be considered. The equiluminance turning curve was established for the recorded VEPs of the luminance changes of the red and green color stimulus, and the position of the equiluminance was used to define the kind and degree of color vision deficiencies. In the test of 47 volunteers, we got the VEP traces and the equiluminance turning curves, which was in accordance with the judgment by the pseudoisochromatic plate used in clinic. The method fulfills the impersonal and quantitative requirements in color vision deficiencies test.

New techniques were established in fabricating cyclic olefin polymer-coated silver (COP/Ag) hollow optical fiber. Low-loss properties in visible region were obtained owing to the smoother layers of silver and polymer. In silver layer plating, a SnCl₂ solution pre-treatment was used to sensitize the inner surface of the glass capillary. A silver layer with an RMS surface roughness of 8 nm was obtained comparing with 18 nm RMS roughness without the pre-treatment. In the liquid-phase coating of the polymer layer, an ambient air of organic solvent was used in the whole process. A smoother polymer layer with RMS roughness of 10 nm was obtained comparing with 20 nm roughness when a normal nitrogen gas-flow was used. The straight and bending loss properties for the hollow fibers have been measured by using a CO₂ laser and a red laser diode at the wavelengths of 10.6 μm and 0.63 μm. The straight losses were 0.4 dB and 1 dB for the hollow fiber (700 μmφ×1 m) made by the new developed fabrication techniques.

At the present time, there are many kinds of x-ray imaging machines, and the x-ray image intensifier is the key component of it. In the hospitals, those x-ray imaging machines, which are equipped with the vacuum image-intensifier tubes (very heavy), are very ponderous (up- to-100-pound heft). It is particularly difficult to move and operate; by using the MCP x-ray intensifier-tube (it is also a vacuum tube), the system can be simplified, but the field of view is small because of the complex technics of MCP. These years, although the flat-panel detector is very advanced and it has big visual field, it is too expensive to be used in the daily living. In this paper, a new kind of x-ray image intensifier is put forward, which is coupled to million-pixel CCD by lens, is mainly composed of the intensifying screen and the brightness intensifier. It has the advantages of big visual field and low price. At the very beginning of this paper, the new kind of image intensifier and its imaging performance are introduced in detail. Then the performance characteristics of the intensifier are described. It is concluded that the relation between the output brightness that the brightness intensifier detects and the size of the intensifying screen obeys the inverse square law and the resolution of the image intensifier depends on the resolution of its components. After we discussed all these relations among the visual field and the output brightness and the resolution, we put forward the optimal coupling among all parts of the x-ray machine.

As an analysis tool, SPM has been broadly used in biomedicine in recent years, such as AFM and SNOM; they are effective instruments in detecting life nanostructures at atomic level. Atomic force and photon scanning tunneling microscope (AF/PSTM) is one of member of SPM, it can be used to obtain sample’ optical and atomic fore images at once scanning, these images include the transmissivity image, reflection index image and topography image. This report mainly introduces the application of AF/PSTM in red blood membrane and the effect of different sample dealt with processes on the experiment result. The materials for preparing red cells membrane samples are anticoagulant blood, isotonic phosphatic buffer solution (PBS) and new two times distilled water. The images of AF/PSTM give real expression to the biology samples’ fact despite of different sample dealt with processes, which prove that AF/PSTM suits to biology sample imaging. At the same time, the optical images and the topography image of AF/PSTM of the same sample are complementary with each other; this will make AF/PSTM a facile tool to analysis biologic samples’ nanostructure. As another sample, this paper gives the application of AF/PSTM in immunoassay, the result shows that AF/PSTM is suit to analysis biologic sample, and it will become a new tool for biomedicine test.

A technique has been developed to simultaneously acquire ultrasound and photoacoustic (PA) images base on a linear transducer array. The system uses conventional ultrasound for rapid identification of potential target(s). Once a target is identified, the ultrasound echo and PA signals can be simultaneously obtained with optimized excitation and signal collection sequence. The corresponding ultrasound impedance and optical absorption images can be reconstructed with an algorithm similar to that used for conventional ultrasound imaging. The approach can effectively reduce the artifacts associated in conventional filter back-projection algorithm used in PA imaging by linear scanning. The technique provides a potential approach for practical applications.

Three optometry methods which include auto-refractor, wavefront aberrometer and subjective manual refraction were studied and compared in measuring low order aberrations of 60 people’s 117 normal eyes. Paired t-test and linear regression were used to study these three methods’ relationship when measuring myopia with astigmatism. In order to make the analysis more clear, we divided the 117 normal eyes into different groups according to their subjective manual refraction and redid the statistical analysis. Correlations among three methods show significant in sphere, cylinder and axis in all groups, with sphere’s correlation coefficients largest(R>0.98, P<0.01) and cylinder’s smallest (0.900.01). Auto-refractor had significant change from the other two methods when measuring cylinder (P<0.01). The results after grouping differed a little from the analysis among total people. Although three methods showed significant change from each other in certain parameters, the amplitude of these differences were not large, which indicated that the coherence of auto-refractor, wavefront aberrometer and subjective refraction is good. However, we suggested that wavefront aberration measurement could be a good starting point of optometry, subjective refraction is still necessary for refinement.

The laser-diffraction technique has been applied to design a slit rheometer for measuring red blood cell deformability over a range of shear stress. A laser beam traverses a diluted blood suspension and is diffracted by RBCs in the volume. The diffraction patterns are captured by a CCD-video camera, linked to a frame grabber integrated with a computer. When deforming under decreasing shear stress, RBCs change gradually from the prolate ellipsoid towards a circular biconcave morphology. Both the laser-diffraction image and pressure were measured with respect to time. Which enable to determine the elongation index (EI) and the shear stress. The range of shear stress is 0~35 Pa and the measuring time is less than 2 min. The elongation index (EI) is determined from an isointensity curve in the diffraction pattern using an ellipse-fitting program. The key advantage of this design is the incorporation of a disposable element that holds the blood sample, which enables the present system to be easily used in a clinical setting.

An optical differential phase surface plasmon resonance (SPR) technique capable of performing refractive index measurement with accuracy in the order of 5 x 10^-8 is presented. The system makes use of the s-polarization as the reference beam to interfere with the p-polarization, of which the phase has close relationship with the change of surface plasmon resonance conditions at the sensor surface. The extraction of phase information is achieved by performing fringe analysis on the interference pattern captured by a digital oscilloscope. Results obtained from monitoring BSA (Bovine Serum Albumin) binding reaction with BSA antibodies demonstrated that our setup has a sensitivity limit of 7.4 ng ml^-1.

There are two kinds of pathways mediating cellular photobiomodulation, the specific one is mediated by the resonant interaction of light with molecules such as cytochrome nitrosyl complexes of mitochondrial electron transfer chain, singlet oxygen, hemoglobin or photosensentor such as endogenous porphyrines, the non-specific one is mediated by the non-resonant interaction of light with membrane proteins. Some of specific pathways mediating photobiomodulation can damage membrane or cell compartments such as mitochondria, lysosomes, endoplasmic reticulum by photodynamic damage if the light intensity is very high so that photodynamic damage will limit the maximum intensity of the light of photobiomodulation although the non-specific pathways mediating photobiomodulation might not damage cells. As the reciprocity law, the rule of Bunsen and Roscoe, was not obeyed for almost all the studied photobiomodulation, and the light energy reaps the greatest benefit where it is most needed, photobiomodulation was thought to be dominantly mediated by the non-specific pathways although the specific pathways can act as a role, which is supported by the dose relationship research in which the photobiomodulation effects were found to be the SIN function of radiation time in many works on the dose relationship when the intensity is kept constant. The non-specific pathways were mainly mediated by membrane receptors and the ultraweak non-resonant interaction of light with membrane receptors can be physically amplified by the coherent state of membrane receptors and then chemically exemplified by signal transduction according to our biological information model of photobiomodulation supported by its successful cellular, animal and clinic applications.

In photodynamic therapy (PDT), a target tissue with pre-administered photosensitizer is exposed to laser light. The photochemical process produces reaction oxygen species (ROS), such as singlet oxygen and superoxide, and leads to ultimate cell death. A direct monitoring of ROS production during PDT, thus, may provide important information in both basic science and clinical practice. A cypridina luciferin analogue (FCLA) is a chemiluminescence (CL) probe that selectively detects singlet oxygen and superoxide. In this study, FCLA was used as an optical reporter of ROS produced by photosensitization reaction of Photofrin in Hanks solution and the CL was measured by a photomultiplier system operated at single photon counting mode. By varying the amount of PDT dosage (photosensitizer dose, light irradiation fluence rate) and the amount of FCLA, the intensity of CL were investigated. The results showed the FCLA concentration affects the ratio of the signal to background CL. The decay time of the photosensitized CL was approximately 10 sec., after the excitation source was turned off. In addition, the intensity of the CL-FCLA increased with increasing concentration of Photofrin and fluence rate. The work supported the potential application of FCLA-chemiluminescence probe as a dosimetric tool for PDT.

The therapeutic effectiveness of laser-electromagnetism combined therapy in chronic prostatitis is studied. Four patients were treated by irradiating the prostate’s correlative parts and acupoints with 650nm semiconductor laser and pulse electromagnetism respectively. Three of them were recovery and only one was ineffective. This demonstrates the feasibility of using laser-combined electromagnetism for assistant treatment on chronic prostatitis. A further study on combined therapy of chronic prostatitis using 810nm, 650nm semiconductor laser and pulse electromagnetic wave is also introduced.

“Nonablative skin photorejuvenation” is a new treatment for photoaged skin, which is to wound the upper dermis in order to induce dermal fibrosis and improve the clinical appearance. In this paper, the penetration depths of the light emitted by intense pulsed light source (IPLS) were analyzed, and the results show the IPLS was suitable for nonablative skin photorejuvenation. A new method with thermal texture maps (TTM) technology for exploring the mechanisms and repairing processes in the nonablative treatment of photoaged skin was presented.

Two-photon-induced fluorescence spectrum and lifetime of Chlorin-e₆-C₁₅ Monomethyl Ester in tetrahydrofura (THF) are experimentally examined with femtosecond laser pulses at 800 nm from a Ti:sapphire laser. The two-photon excited fluorescence spectra of the molecule are basically similar to those obtained by one-photon excitation. The lifetimes of two-photon and one-photon excitation fluorescence of this molecule in the solution are of the order of 5.2 ns and 4.8 ns respectively. Our experimental results indicate that the two-photon-induced photodynamic processes of Chlorin-e₆-C₁₅ Monomethyl Ester are similar to one-photon-induced photodynamic processes. The two-photon absorption cross section of the molecule is measured at 800 nm as about σ₂^' ≈ 29.1 x 10^-50 cm⁴ • s/photon. As an example for two-photon photodynamic therapy, we also further examine the cell-damaging effects of the Ester. Our preliminary results of cell viability test indicate that Chlorin-e₆-C₁₅ Monomethyl Ester can effectively damage the liver cancer cells BEL-7402 under two-photon irradiation. Our results suggest Chlorin-e₆-C₁₅ Monomethyl Ester may become a potential two-photon phototherapeutic agent.

Light is the primary stimulus for regulating circadian rhythms, seasonal cycles, and neuroendocrine responses in many species, including humans. The major circadian pacemaker in the hypothalamic suprachiasmatic nucleus is entrained to the light/dark cycles from the outside world by circadian photoreceptors which are functionally characterized by the direct sensitivity to light with broad spectrum and the relatively high stability. Chromophototherapy mediated by the color indirect effect (CIE), the physiological and psychological effects of color resulting from color vision, is functionally characterized by the sensitivity to light with narrow spectrum and the relatively low stability. In this paper, the mechanism of chromophototherapy used in sports medicine and rehabilitation, especially in treating overtraining syndrome (OTS), was discussed. Although several hypotheses and the corresponding OTS treatments have been proposed, each only explains and treats a selective aspect of OTS. On the one hand, an autonomic or neuroendocrine imbalance is hypothesized as underlying by Lehmann et al so that the described functional alterations of pituitary-adrenal axis and sympathetic system can explain persistent performance incompetence in affected athletes beside additional mechanisms. On the other hand, cold color (green, blue or violet) excites parasympathetic subsystem and hot color (red, orange or yellow) excites sympathetic subsystem for chromophototherapy. The conclusion was then drawn that chromophototherapy might be a good therapy to treat OTS.

For some non-invasive measurement on human skin surface or fingernail, the information of dermis is useful and usually the epidermis or fingernail disturbs the light signal that carries information of dermis. In this paper, a two-layered media model was developed to simulate human finger. The first layer simulates the epidermis or fingernail and the second layer simulates dermis and tissue under dermis. A beam of light normally hits on the two-layer model, some photons travel through the first layer and return to the surface, some photons travel through the first and the second layers and then return to the surface. The light from the first layer is defined as noise and the light from the second layer is defined as signal. The intensity distributions of light from the first layer and the second layer were experimentally studied on the model surface. The distribution of SNR on the surface was obtained and the results show that there is an optimal source-detector distance where the SNR is greater than that at other source-detector distance. The results are useful for non-invasive measurement on skin.

The noninvasive measurement of human blood glucose has been a hotspot for a long time to all clinical workers over the world. In this paper the noninvasive measurement of human blood glucose with diffusion reflectance NIR spectrum method is presented. The thumb fingertip, the palm and the wrist with vein are chosen for the collection of diffusion reflectance NIR spectroscopy from six different age healthy volunteers using Nexus-870 and its NIR fiber port smart accessory. The calibration model is set up in 7500~8500cm^-1 region that has the absorption of the glucose using Partial Least Squares (PLS) method with the first and second derivative spectral that had been smoothed and baseline corrected for single volunteer. The actual blood glucose value is determined by an ultraviolet spectrophotometer. The model with the spectrum obtained at the wrist is better than from other part for all volunteers, and it is much steadier with the second derivative pretreatment spectral than with the first derivative ones. The correlative coefficients are all over 0.93772; RMSECs are all less than 0.310 and the max differences are between -0.6mmo/L and +0.8mmo/L with the second derivative method. Some samples are kept for prediction with their own model. The differences are under 0.875529mmol/L.

Both Raman and infrared spectrum measure vibrational transitions in molecules, so they can detect structure and clinical medical character of material in molecule level. Since human blood keeps in close touch with tissue, it may have some symptoms in the blood when functional disorder happens. For this reason, people have already developed a lot of methods to investigate the feasibility of using it to diagnose and therapy, especially in the orientation of non-invasive measurement. In this paper the principles of two kinds of spectra were analyzed and discussed first, involving the advantages and disadvantages in actual research. Then, according to different composition and research direction of human blood, we introduced the research progress of this field at present. Finally the difficulty we met and the expectation in the future are discussed.

The physiological meaning of cerebral oxygen saturation absolute values and the oxygen metabolism of piglet with hypoxia-ischemia (HIE) were researched. The subjects were two piglets. During the total experiment of hypoxia then recovery, the regional cerebral tissue oxygen (rScO₂), pulse oxygen saturation (SpO₂) were detected non-invasively and the jugular oxygen saturation (SjO₂), arterial oxygen saturation (SaO₂) were given invasively. The results show that because SjO₂ was equal to or larger than rScO₂ and SaO₂ > ScO₂, rScO₂ cannot be determined by the weighted sum of SjO₂ and SaO₂ which had been presented in some papers. According to above-mentioned analysis, the ecchymoma and pathological changes of the vessels due to HIE may be another contribution of rScO₂. SjO₂ was correlated with SaO₂ (R=0.996 and 0.962 for two piglets) and the values of (SaO₂-SjO₂) are close to constants (29.3±8% and 30.3±8%).It means that because the subjects were under anesthesia, the oxygen consumption of cerebral tissue kept constants.

Various optical imaging techniques had been brought out and studied for imaging in turbid media such as bio-tissues. However, there’re always limitations or problems here and there. Among them many are related to light scattering in the media. In this paper we provide a new insight into these questions and tried to give some possible explanations. The distribution of backscattered photon numbers on scattering events of light was studied for what is to our knowledge the first time. A Monte Carlo (MC) method was used to calculate how many photons will reemit from media as their scattering events increase. Various illuminant conditions and detecting methods were simulated, results show that instead of easily took feint that photons reemitted from tissue increases/decreases as scattering events accumulates; backscattered photon numbers increase firstly and decrease later. The peak position, peak value and exact curve shape depend on illuminant conditions, monitoring method and tissue optical parameters. From these curves two basic conclusions could be drawn as follows: (1) the chance of single scattering photon packet exiting the tissue exists, but decreases dramatically as internal source moves deep into media. This suggests that theoretically many coherent imaging approaches are feasible, but good imaging depth requires high power density, this leads to difficulty in improving imaging depth. (2) as for the majority of backscattered photons, the number of average scattering events has a close relationship with mean free path -- one of the most important tissue optical parameters. Our simulation results will lead to several interesting explanations to many present problems.

Optical Coherence Tomography (OCT) is a noninvasive cross-sectional imaging modality capable of measuring tissue morphology and function high spatial resolution. The amplitude of the intero-metric heterodyne signal provides a profile of sample reflectivity related to its microstructure and its phase may enable bi-directional blood flowing imaging, termed Color Doppler OCT (CDOCT). In order to evaluate and improve the imaging properties as well as find the appropriate image-processing algorithms, several theoretical models of OCT of biological tissue have been proposed. Most of these models are based on the consideration of both the single scattering and multiple scattering processes of the light within the tissues. However, all these models omitted the effects of moving scatterers on measured backscattering signal. We show that inclusion of this effect is more realized and is of great importance in the calculation and interpretation of the heterodyne signal, evaluation of the system performance as well as calculating the maximum imaging depth of the OCT scanners. The analytical results and a sample result is given.

Early detection of gastrointestinal cancer is essential for the patient treatment and medical care. Endoscopically guided biopsy is currently the gold standard for the diagnosis of early esophageal cancer, but can suffer from high false negative rates due to sampling errors. Optical coherence tomography (OCT) is an emerging medical imaging technology which can generate high resolution, cross-sectional images of tissue in situ and in real time, without the removal of tissue specimen. Although endoscopic OCT has been used successfully to identify certain pathologies in the gastrointestinal tract, the resolution of current endoscopic OCT systems has been limited to 10 - 15 m for clinical procedures. In this study, in vivo imaging of the gastrointestinal tract is demonstrated at a three-fold higher resolution (< 5 m), using a portable, broadband, Cr⁴⁺:Forsterite laser as the optical light source. Images acquired from the esophagus, gastro-esophageal junction and colon on animal model display tissue microstructures and architectural details at high resolution, and the features observed in the OCT images are well-matched with histology. The clinical feasibility study is conducted through delivering OCT imaging catheter using standard endoscope. OCT images of normal esophagus, Barrett's esophagus, and esophageal cancers are demonstrated with distinct features. The ability of high resolution endoscopic OCT to image tissue morphology at an unprecedented resolution in vivo would facilitate the development of OCT as a potential imaging modality for early detection of neoplastic changes.

Optical coherence tomography (OCT) has been developed not only for morphological imaging, but also for functional imaging. By combining Doppler velocimetry with optical sectioning capability of OCT, we developed one branch of functional OCT (F-OCT) termed optical Doppler tomography (ODT). This newly developed fiber-based F-OCT system can provide structural image and Doppler image simultaneously, and is ready for extension to another branch of F-OCT termed as polarization-sensitive OCT (PS-OCT). Measurements of in vivo human skin and fresh milk flowing inside capillary tube are presented to demonstrate the capability of the developed system.

Currently, one of the current limitations of Optical Coherence Tomography (OCT) is its penetration depth and imaging contrast because of the fact that the complex morphological nature of biological tissue, especially skin tissue. In this work, we investigate the synergistic effect of oleic acid and propylene glycol on optical clearing of skin tissue in vitro, improve OCT imaging contrast and penetration depth. The results demonstrate the optical clearing effect after topical application of the hyperosmotic agents of PG80 (80% propylene glycol) and OA PG80 (0.1 M oleic acid in 80% propylene glycol), which enhances not only the depth-imaging capability, but also the imaging contrast of optical coherence tomography. It should be noticed that OA PG80 obtained the better effect in a shorter time than PG80 alone. Therefore, in terms of optical application and clinical safety, OA PG80 could be better choice to improve penetration depth and imaging contrast of OCT technique.

Optical coherence tomography (OCT) is a new modality used to image biological tissues that weakly scatter and absorb light. It was demonstrated that this technique provides image with micrometer resolution in a noncontact and noninvasive way. Traditional OCT is time domain OCT (TDOCT). In this method the length of the reference arm in an interferometer is rapidly scanned over a distance corresponding to the imaging depth range. The mechanism of scanning largely limits the acquisition speed and makes real-time imaging impossible. In recent years a new model OCT based on Fourier domain interferometry is emerged, we called it spectral OCT (SOCT) or Fourier domain OCT (FDOCT). SOCT can avoid scanning of the reference, thus can reach very high acquisition speed. In this paper, spectral OCT related theories and techniques are reviewed. This paper consists of three sections: principle of SOCT, different sep-ups, recent progress and advance.

Concept of penetration depth of diffused photons migrating in turbid medium is introduced, and subsequently, distribution of penetration depth and mean penetration depth in three-layered media are investigated by using of Monte Carlo simulation technique. An optimal source-detector separation is derived from the mean penetration depth referring to monitoring the change of chromophore concentration of the sandwiched layer. In order to verify the separation, we perform Monte Carlo simulations 80 times with varied absorption coefficient of the sandwiched layer. All these diffuse reflectance of 80 times of Monte Carlo simulations are used to construct a calibration model with the method of PLS. High correlation coefficients and low RMSEP at the optimal separation have conformed correctness of the selection.

The spectroscopic characteristics of autofluorescence for the nasopharyngeal carcinoma in vitro and nasopharyngeal carcinoma cells (CNE cells) were investigated, respectively. The characteristics of fluorescence agree with the results that deduced from the nasopharyngeal carcinoma in vivo, and the optimal excitation-emission wavelength was found at 350-500 nm. Secondly, the selectivity and optimal time for optical diagnosis of nasopharyngeal carcinoma by using the new photosensitizer of Hematoporphyrin Monomethyl Ether (HMME) has been demonstrated and determined by incubated CNE cells with HMME. The fluorescence emission peaks of 615 and 675 nm characterized the selective accumulation of HMME in CNE cells, and the optimal time for optical diagnostics with HMME was about 140 mins after clinic intravenous administration. Moreover, when the concentration of HMME in CNE cells below 32 μg/mL, the fluorescence intensity versus HMME concentration reveals an obvious linearity. Finally, the fluorescence intensity of CNE cells increases linearly with concentration over the entire range up to 9.0E+05 cells/mL. These results can be used to helpfully improve the accuracy of optical diagnosis for nasopharyngeal carcinoma.

This paper reports the principle and applications of the combination technique of optical trapping and Raman spectroscopy for real-time analysis of single living cells. We demonstrate that the information of each substance inside a captured cell can be retrieved by the Raman spectrum of the cell. The effect of alcohol solution on single human Red Blood Cell (RBC) is investigated using near-infrared laser tweezers Raman spectroscopy (LTRS). The significant difference between the spectrum of fresh RBC and the spectrum of RBC exposed to alcohol is observed due to the degradation of RBC. We also present the preliminary study result on the diagnosis of colorectal cancer using LTRS system.

Fourier transform in-infrared and near-infrared Raman spectroscopies were used to study human red cell. The assignment of characteristic groups of human red cell structure was basically confirmed. The intensity of different Raman shift signal has different varying law when the power of laser is changing and it doesn’t satisfy the simple linearity. Laser Raman spectroscopy combining with infrared spectroscopy is an effective method to study the structure of human red cell.

Acetic acid solution can emit visible fluorescence when induced by UV-light. With emitting spectrum profiles dissimilar on the whole, the fluorescent intensity changes too when the excited light alters from 230nm to 300nm. There are two spectral bands on the whole, one central wavelength is located at 307nm and the other is at 400nm. The relationship between the fluorescence relative intensity and the excited-light wavelength is described in polynomial fit. The optimal excited light is obtained both by the experiment data and the polynomial fit of the data. Investigation on the intrinsic fluorescence spectrum of acetic acid solution and its characteristics will contribute to the study of the fluorescence spectra when acetic acid serves as a solute and hydrolysis catalyst. Especially, this study will also help to offer the experiment basic for the theoretic research of the interaction of acetic acid and water molecule.

With the increase of people’s living standard and the changes of living form, the number of people who suffer from hypercholesterolemia is increasing. It is not only harmful to heart and blood vessel, but also leading to obstruction of cognition. The conventional blood detection technology has weakness such as complex operation, long detecting period, and bad visibility. In order to develop a new detection method that can checkout hypercholesterolemia conveniently, spectroscopy of cholesterol in hypercholesterolemia serum is obtained by the multifunctional grating spectrograph. The experiment results indicate that, under the excitation of light-emitting diode (LED) with the wavelength at 407 nm, the serum from normal human and the hypercholesterolemia serum emit different fluorescence spectra. The former can emit one fluorescence region with the peak locating at 516 nm while the latter can emit two more regions with peaks locating at 560 nm and 588 nm. Moreover, the fluorescence intensity of serum is non-linear increasing with the concentration of cholesterol increases when the concentration of cholesterol is lower than 13.8 mmol/L, and then, with the concentration of cholesterol increase, the fluorescence intensity decreases. However, the fluorescence intensity is still much higher than that of serum from normal human. Conclusions can be educed from the experiments: the intensity and the shape of fluorescence spectra of hypercholesterolemia serum are different of those of normal serum, from which the cholesterol abnormal in blood can be judged. The consequences in this paper may offer an experimental reference for the diagnosis of the hypercholesterolemia.

A new virtual instrument of spectroscopy based on LabVIEW was developed for the diagnosis system of nasopharyngeal carcinoma. Some methods of the signal acquisition of wavelength calibration were devised and then discussed in detail including the LabVIEW programming. The mechanical part of the diagnosis system is also presented in this paper.

Prostate-specific antigen (PSA) is an androgen-dependent glycoprotein protease (M.W. 33 kDa) and a member of kallikrein super-family of serine protease, and has chymotrypsin-like enzymatic activity. It is synthesized by the prostate epithelial cells and found in the prostate gland and seminal plasma as a major protein. It is widely used as a clinical marker for diagnosis, screening, monitoring and prognosis of prostate cancer. In normal male adults, the concentration of PSA in the blood is below 4 ng/ml and this value increases in patients with the prostate cancer or the benign prostatic hyperplasia (BPH) due to its leakage into the circulatory system. As such, systematic monitoring of the PSA level in the blood can provide critical information about the progress of the prostatic disease. We have developed a compact integral system that can quantitatively measure the concentration of total PSA in human blood. This system utilizes the fluorescence emitted from the dye molecules attached to PSA molecules after appropriate immunoassay-based processing. Developed for the purpose of providing an affordable means of fast point-of-care testing of the prostate cancer, this system proved to be able to detect the presence of the PSA at the level of 0.18 ng/ml in less than 12 minutes, with the actual measurement taking less than 2 minutes. The design concept for this system is presented together with the result for a few representative samples.

This work was to explore near-infrared (NIR) Raman spectroscopy for distinguishing tumor from normal bronchial tissue. A rapid NIR Raman system was used for tissue Raman studies. High-quality Raman spectra in the 700-1800 cm^-1 range can be acquired from human bronchial tissues in vitro. Raman spectra differed significantly between normal and malignant tumor tissue, with tumors showing increased nucleic acid, tryptophan, phenylalanine signals and decreased phospholipids, proline, and valine signals than normal tissue. Raman spectral shape differences between normal and tumor tissue were also observed particularly in the spectral ranges of 1000-1100, 1200-1400, and 1500-1700 cm^-1, which are related to the protein and lipid conformations and CH stretching modes in nucleic acids. The ratio of Raman intensities at 1445 cm^-1 to 1655 cm^-1 provided good differentiation between normal and malignant bronchial tissue, suggesting that NIR Raman spectroscopy may have a significant potential for the noninvasive diagnosis of lung cancer in vivo based on optical evaluation of biomolecules.

Ultrafast lasers have found increasing use in scanning optical microscopy due to their very high peak power in generating multiphoton excitations. A mode-locked Ti:sapphire laser is often employed for such purposes. Together with a synchronously pumped optical parametric oscillator (OPO), the spectral range available can be extended to 1050-1300 nm. This broader range available greatly facilitates the excitation of second harmonic generation (SHG) and third harmonic generation (THG) due to better satisfaction of phase matching condition that is achieved with a longer excitation wavelength. Dental sections are then investigated with the contrasts from harmonic generation.

Ras/Raf signaling pathway is an important signaling pathway that governs cell proliferation, differential and apoptosis. Low-energy laser irradiation (LELI) was found to modulate various processes. Generally, cell proliferation is induced by low doses LELI and apoptosis is induced by high doses LELI. Mechanism of biological effect of LELI has not been clear. Recently, activation of MEK (mitogen-activated protein kinase) and ERK (extracellular-signal-regulated kinase), which are downstream protein kinases of Ras/Raf, are observed during LELI-induced cell proliferation by immunoprecipitation and western blot analysis. RaichuRas reporter consisting of fusions of H-ras, the Ras-binding domain of Raf (RafRBD), a cyan fluorescent protein (CFP) and a yellow fluorescent protein (YFP). Therefore, intramolecular binding of GTP-Ras to RafRBD brings CFP close to YFP and increases FRET between CFP and YFP. Human lung adenocarcinoma cell line (ASTC-a-1) was transfected with the plasmid (pRaichuRas) and then treated with LELI at dose of 60J/cm². Effect of LELI on Ras/Raf in physiological condition of living cells was observed by fluorescence resonance energy transfer (FRET) technique during lung adenocarcinoma cell apoptosis induced by high dose (60J/cm²) LELI. Experimental results showed that after high dose LELI treatment, the binding of Ras and Raf decreases obviously, Ras/Raf signaling pathway deregulates and cell apoptosis occurs.

Diagnostic techniques based on optical spectroscopy have the potential to link the biochemical and morphological properties of tissues. Light-induced fluorescence (LIF) spectroscopy as a noninvasive “optical biopsy” method has been widely used to detect small lesions in vivo. Confocal fluorescence spectroscopy provides a tool for optical sectioning of tissue and provides an approach for identifying small shifts in the emission spectra that are caused by intracellular microenvironment factors. The ability to demarcate abnormal and normal tissue with a confocal spectroscopy system depends on the ability of interpreting the source of fluorescence within the samples. It is realized by spatially dispersing the fluorescence collected with a fiber that serves as the pinhole aperture of the confocal system. In order to tracing the autofluorescence spectral signals of tissue layer by layer, a confocal fluorescent spectroscopy system has been set-up. Experiments have been carried out with fluorescent phantom and animal models. With an axial resolution of 10um in animal tissues, this confocal spectral system observed the spectral differences in spectral shape and spectral peak position among different layers of tissue illuminated with 349nm laser. It was also found that the fluorescence intensity is depth-dependent. In conclusion, confocal fluorescence spectroscopy can provide more diagnostic information due to its ability of optical sectioning. It’s hopeful that a confocal spectral system can detect cancer at much earlier stage.

Activation of caspase-3 is a central event in apoptosis. A fluorescence techniques, fluorescence resonance energy transfer (FRET), was used to study the dynamic of caspase-3 activation during apoptosis induced by tumor necrosis factor TNF-α in living cells. The FRET probe consists a CFP (cyan fluorescent protein) and a Venus (YFP mutant, yellow fluorescent protein) with a specialized linker containing the caspase-3 cleavage sequence: DEVD (Luo et al., 2001). Human lung adenocarcinoma cell line (ASTC-a-1) were stably expressed with the FRET probe and then were treated by TNF-α, respectively. Experimental results showed that FRET could monitor more insensitively the dynamic of caspase-3 activation in real-time in vivo, and this technique will be highly useful for correlating the caspase-3 activation with other apoptotic events and for rapid-screening of potential drugs that may target the apoptotic process.

Photodynamic therapy (PDT) is a novel and promising cancer treatment that employs a combination of a photosensitizing chemical and visible light, induces apoptosis in cell, and activation of caspase-3 is considered to be the final step in many apoptosis pathways. The changes of caspase-3 activation in cell during TNFα- and photodynamic therapy-induced apoptosis was measured by fluorescence resonance energy transfer (FRET) analysis. FRET probe consisting of fusions of an enhanced cyan fluorescent protein (ECFP), Venus and a linker peptide containing the caspase-3 cleavage sequence DEVD was utilized. Therefore, activated caspase-3 cleaved the linker peptide of FRET probe and disrupted the FRET signal. Human lung adenocarcinoma cell line (ASTC-a-1) were stably transfected with the plasmid (ECFP-DEVD-Venus) and then were treated by TNF-α and PDT, respectively. Experimental results indicated that caspase-3 activation resulted in cleavage of linker peptide and subsequent disruption of the FRET signal during TNFα- and photodynamic therapy-induced apoptosis, and that the activation of caspase-3 induced by photodynamic therapy was faster than that induce by TNF-α. The study supports that using FRET technique and different recombinant substrates as FRET probes could be used to detect the process of PDT-induced apoptosis and provide a new means to investigate apoptotic mechanism of PDT.

In order to assess the mutagenic effects of ultraviolet (UV) and solar irradiation on DNA, Raman spectroscopy is used to investigate the structural changes of calf thymus DNA in aqueous solution after ultraviolet radiation. The damage to DNA induced by UV is usually carried out with a germicidal lamp, which mainly covers the region of UVC. For the sake of making a complete investigation of the damage to DNA by ultraviolet radiation, we use different intervals of UV (UVA, UVB and UVC) to conduct our experiments. Such UV radiation is obtained from a solar UV simulator (SS) made by us, which can be conveniently adjusted to different wavelengths and radiation intensities. From the comparison of the Raman spectra of DNA in aqueous solution before and after ultraviolet radiation, it can be inferred that the UV-C has a serious influence on the DNA molecular conformation and damages the hydrogen bonds and bases, UV-B only damages the DNA molecular structure to some extent while UV-A almost does not play an impact on the DNA molecular conformation. For all the three regions of UV, the damage increases with the elongation of irradiation time and is first observed in pyrimidine-dimer bases and deoxyribose. The experimental results also partly support the formation of several types of dimeric lesions between adjacent pyrimidine bases, most notably cyclobutane pyrimidine dimers (CPDs) and the Dewar valence isomers.

A novel confocal microarray scanner was introduced, which employed a 532nm laser and a 635nm laser to excite Cy3 and Cy5 fluorophores respectively. The fluorescent signal was detected using a photomultiplier tube (PMT) sequentially. One dimension scanning of the microarray slide was performed by a telecentric objective with a moving coil optical scanner; the other dimension was scanned by a stepping motor driving the precise guidance. Experimental results show that scanning resolution of the presented microarray scanner can reach 5 microns, its dynamic range is near 4 orders of magnitude and the limit of detection is 1.12 about fluors per square micron. The cross-talk error is eliminated almost completely by its sequential scanning mode.

Optical transfer function is widely used to evaluate the imaging performance of an optical system. Combined with confocal scanning technology, f-theta lens can increase the reading speed for microarrays greatly in guarantee of sufficient resolution and fluorescence collection efficiency, compared with micro-array analyzers that adopting mechanical scanning. In this paper, the characteristics of a confocal scanning f-theta objective lens, which was used in micro-array analyzing instrument, were analyzed by means of optical transfer function. In the whole system, laser passed through the f-theta lens, and arrived at the microarray slide where fluorophores were excited. Fluorescence emitting from the micro-array slide was collected by the same f-theta lens, and was captured by a detector. As a laser illumination system, the objective lens had a smaller stop aperture. As a fluorescence collection system, it had a bigger stop aperture. In conclusion, optical transfer function for the whole system, from source to detector, is the combination of that of the laser illumination, a coherent system, and that of the fluorescence collection system, an incoherent system. Uniformity of laser illumination at the micro-array slide was analyzed using optical transfer function during the course of scanning. The influence of aberrations on optical transfer function is given. The simulating results for above characteristics are also presented.

The most successful biochip technologies today are flat microarray and suspension microarray. Usually probes are fluorescence labeled. The fluorophores are excited by laser with a special wavelength. Because the fluorescence signal is very weak, it is hard to detect. The limitation of detection (LOD) is an important index of microarray analyzer. The dependence of LOD of flat and suspension microarray analyzer based on CCD and the fluorescent intensity on characters of excitation light optical system and fluorescence collection optical system as well as the parameters of elements system has been analyzed in detail based on the system configuration. A formula of LOD and fluorescence signal intensity depending on those parameters has been established. The study analyzed system limitation of detection (LOD). Also present a formula of minimal detectable fluorescent molecule numbers as the function of each parameter of microarray analyzer based on CCD. Estimated LOD of our suspension microarray detection system is about 7.9 fluorophores/μm² at exposure time 1s.

This paper presents a novel method for establishing a two-dimensional laminar fluidic suspension array which is analyzed by using time delay integration (TDI) CCD imaging technology in parallel. The method will make suspension array technology (SAT) bear high throughput as well as its flexibility. Basically, bioassays are conducted on the surface of fluorescent-dyed beads. With each bead set (i.e., multiple beads with the same fluorescent signature) having a slightly different fluorescent signature, probes are first attached to a particular bead set and then hybridized with labeled samples or targets. Two different kinds of encoding dyes are excited by red laser (635 nm, 20mw), their emission wave length are 660nm, 720nm, respectively. Fluorescent dye of reporter molecules was excited by green laser (532nm, 20mw), emitted at 580 nm. The liquid sample was pumped into micro-reservoir by a linear motor. As the velocity of liquid sample is so slow (10mm/s) it is easy to form a laminar fluidic field in the middle of the micro-reservoir. In the direction of laser propagation the size of reservoir is 0.1mm so the laminar liquid can be treated as a two-dimensional fluidic plane. The size of detection area depends on size of micro-sphere and CCD imaging area. The three kinds of fluorescence signals were focused by a lens and then split by mirrors. Fluorescence pass through three band-pass filters (±20nm) before collected by three TDI-CCDs respectively. With these high-quality filters the cross-talk between signals was diminished significantly. The analysis speed is about 2x10³ micro-spheres per second, which is much higher than that obtained from currently cytometry method (about 10² micro-spheres to the same size micro-spheres).

In this paper, the microfluidic chips and the corresponding detection system were briefly introduced. The microfluidic chips have been widely applied nowadays, which can meet the norm of general detection instruments that must have high SNR (signal-to-noise ratio) and can detect the object at the density of 10^-9 (Mol/L). The influencing factors in improvement of the SNR were mainly addressed. By studies of various detection principles, the con-focal theory and laser induced fluorescence (short for LIF) which can generate better signal and reduce stray light are finally adopted to improve SNR of the overall system; From the comparison of various optical schemes, the reflection design is chosen due to the improvement of light source efficiency and reduction of stray light; the value of the numerical aperture and the size of pinhole can be calculated by formula to exert influence on the SNR. The fluorescence wavelength scopes, was also analyzed so as to apply appropriate laser, spectral filter and PMT. Because of the need of six-way high voltage for separate control, the amplification system must be analyzed and designed to avoid influencing SNR; for better SNR, software has also been programmed.

In conventional optical tweezers system a high numerical aperture (NA) objective is employed both to image and to generate a gradient force toward the focus on sample particles, so the system is complex and expensive especially for the multi-optical-tweezers system. We built a novel simple optical trapping system based on a lensed optical fiber probe. This new method offers several other advantages over the conventional optical tweezers. The trapping system we built includes a laser coupling unit, a multi-dimensional probe manipulating unit, a sample nano-positioning unit, and a microscopy imaging unit. Based on the system, a yeast cell is trapped and manipulated on the chamber bottom by the lensed fiber probe, and the optical trapping forces acting on the yeast cell as a function of the offset are measured and discussed in different directions by the static method and the dynamic one respectively with various powers. The results by the two measurement methods coincide with each other, and the detail experimental procedure and the data processing of the two methods are introduced in this paper.

A novel method to measure the total amount of bacteria in raw milk is introduced in this paper. This method involves optics, color theory and biology. In this method the total amount of bacteria in raw milk is measured according to the color change caused by chemical reaction. The study proves that the total amount of bacteria in raw milk can be measured by this method with high speed and accuracy. Besides, this method is easy operating and very economical. These qualities will surely make it a favorite in the measurement of the total amount of bacteria in raw milk in the future.

Polyaniline membrane is a conductive polymer, widely used as a current carrier for electrochemical and biological matters, and as a sensor. It is important to control the thickness of polyaniline membrane in measuring current of electrochemical reaction and beneficial to evaluate the quality and thickness of the membrane by using laser confocal scan microscope. After inputting 0.5ml of aniline and 355mg of Na₂SO₄ into 25ml of pH2.0 buffer solution compound with HCl/KCl, a polyaniline membrane is deposited on a Pt wire of Φ0.8mm in diameter with the constant potential anode oxidation method in the CHI660b set, at a voltage of 0.75 Volt, the process of which takes 240 seconds. The polyaniline membrane is inspected with laser confocal scan microscope, at respective wavelengths of 488nm and 633nm. Then the various images are taken at 40×objective lens and different focal lengths. There are many light and shade stripes on the images, parts of which are closed, while others are unclosed curves. The polyaniline membrane is evaluated in terms of its width intervals of the stripes, thickness and uniformity, by means of image analyzing using the laser confocal scan microscope.

The time resolved propagation of ultrashort Gaussian beams laser pulses within turbid tissues is simulated by a Gaussian integrated methods. The various rules of the ultrashort pulse at different shape and pulsewidth in semi-infinite boundary conditions versus the turbid tissues for various scattering coefficients μ_s, absorption coefficients μ_a, scattering phase functions ρ(Θ), and the average cosine of the scattering angle g are presented.

A modified direct method for subtracting axial scattered light was put forward, that is, when the collimated transmission measured, the axial scattered light was deducted by a small angle scattered light with the same beam size. And μ_t values of two different samples of human whole blood were measured at laser wavelengths of 488,632.8 and 1341.4nm, respectively. It showed that μ_t was different for the same blood sample at different wavelength and for different blood sample at the same wavelength.

Monte Carlo method is used to simulate light distribution in human artery of three layers that is irradiated respectively by two different surface photon sources (Guassian beam and flat beam) of 0.06cm radii at wavelength of 633nm. Fluence, diffuse reflectance and diffuse transmission distribution of the tissue are given when the two surface photon sources illuminate the tissue respectively. The influence of the shape of the incident beam on the above parameters, and that of the refractive index n on the diffuse reflectance Rd and absorptance A of the tissue, are discussed. The obtained results are: the diffuse reflectance Rd and fluence Φ are mainly distributed in radial scale of the size of the incident beam, and the influence of the shape of the incidence beam on the radial distribution of Rd and Φ is also in the scale of the size of the incident beam, whereas that of the shape of the incident light beam on the diffuse transmission is little. Rd is linearly decreased with the increasing of n in each layer tissue, but the influence of n in deeper layer tissue on Rd is little; absorptance is linearly increased with the increasing of n in each layer tissue. Therefore, the refractive index is a very important parameter in biotissue.

A novel method combining the PCA-NN algorithm established on the single-layer tissue model and the genetic algorithm based on the two-layer diffusion model has been presented to determine the optical properties of the two-layer medium from the steady-state spatially resolved diffuse reflectance. In detail, we firstly employ the PCA-NN algorithm established on the semi-infinite tissue model to extract the optical properties of the top layer from the spatially resolved reflectance that results from the photons migrating mainly within the top layer. With the knowledge of the optical properties of the top layer, the optical properties of the bottom layer are then obtained by use of the genetic algorithm for fitting the two-layer diffusion model to the reflectance data far from the source. The method was validated using the Monte Carlo generated reflectance for the two-layer medium of skin overlying fat or skin overlying muscle. And, the skin thickness was assumed to be known a priori and fixed at 5 mm. The results showed that all the optical properties of two layers can be determined by the method with the accuracy of better than 10%.

In this paper, with reference to practical applications, we investigate the accuracy of the PCA-NN method in determining the optical properties μ_a and μ_s' from the spatially resolved relative reflectance data produced by Monte Carlo simulations. To test prediction performance of PCA-NN from the reflectance data with different lengths and different measurement noises, we constructed six PCA-NNs respectively corresponding to data length = 5, 10, 15, 20, 25 and 30 mm, which were trained by higher precision reflectance produced with photons = 10⁷. Then lower precision reflectance generated with photons = 10⁴, 2 × 10⁴, 5 × 10⁴, 7 × 10⁴, 10⁵, 2 × 10⁵, 5 × 10⁵, 7 × 10⁵ and 10⁶ were inputted to PCA-NNs to extract μ_a and μ_s' and the accuracy of μ_a and μ_s' was calculated, respectively. The results showed that for the reflectance with the same data length, the prediction errors of μ_a and μ_s' increase as the data noise increases; but for the reflectance with the same data precision, the errors decrease as the data length becomes longer. In conclusion, the preliminary results in this paper provide a guideline for choosing appropriate measurement conditions or estimating the prediction errors in reality.

We report on the development of a multispectral multiphoton fluorescence lifetime imaging microscopy (MM-FLIM) system that is the combination a streak camera, a prism spectrophotometer, a femtosecond Ti: Sapphire laser and a fluorescence microscope. This system is versatile with multispectral capability, high temporal (10ps) and spatial (0.36μm) resolution and can be used to make 3-dimensional (3D) (x-y-z) multiphoton fluorescence intensity, spectrally resolved intensity and lifetime measurements with a single detector. The system was calibrated with a F-P etalon and a standard fluorescent dye and the lifetime value obtained was in good agreement with the value reported in the literature. Preliminary results suggest that this MM-FLIM system has integrated high temporal, spatial, and spectral resolution fluorescence detection in one microscopy system. Potential applications of this system include multiwell imaging, tissue discrimination, intracellular physiology and fluorescence resonance energy transfer imaging.

Two-photon excited fluorescence lifetime imaging (2P-FLIM) provides a more direct and precise approach to fluorescence resonance energy transfer (FRET), which allows studying the dynamic behavior of protein-protein interactions in living cells. In this paper, we describe the combination of a Leica TCS SP2 laser scanning microscope and a time-correlated single photon counting (TCSPC) lifetime imaging module developed by Becker & Hickl for two-photon excited fluorescence lifetime imaging. This 2P-FLIM system was used for FRET study on the interaction of heat shock protein hsp27 with p38 MAP kinase in the single living cell. Results show that the reduction in donor (CFP) lifetime in the presence of acceptor (YFP) reveals interactions between the two proteins.

Support vector machine (SVM) is a new statistical learning method. Compared with the classical machine learning methods, SVM learning discipline is to minimize the structural risk instead of the empirical risk of the classical methods, and it gives better generative performance. Because SVM algorithm is a convex quadratic optimization problem, the local optimal solution is certainly the global optimal one. In this paper a SVM algorithm is applied to detect the micro-calcifications (MCCs) in mammograms for the diagnostics of breast cancer that has not been reported yet. It had been tested with 10 mammograms and the results show that the algorithm can achieve a higher true positive in comparison with artificial neural network (ANN) based on the empirical risk minimization, and is valuable for further study and application in the clinical engineering.

Electrical impedance tomography (EIT) is a non-invasive imaging technique in medicine and industry. It can be used for determining the distribution of electrical impedance inside a body based upon current and voltage measurements made at the body’s surface. EIT is a non-linear inverse problem and the reconstruction problem is more complex and difficult. Estimation of the location and distribution of multi-conductivity distribution sources within the body, based on voltage recording from the source localization, is one of the fundamental problems in EIT. Independent component analysis (ICA) is a way to resolve signals into independent components based on the statistical characteristics of the signals. It is a method for factoring probability densities of measured signals into a set of densities that are as statistically independent as possible under the assumptions of a linear model. Under the approximate condition the independent component analysis is used to pre-process the acquired voltage measurements for EIT reconstruction in this paper. By using ICA the measured EIT voltage data can be separated into several independent component activation maps, in which the reconstruction algorithm is performed in order to obtain individual conductivity distributions. In our experiment the modified iterative reconstruction algorithm with an exponentially weighted least square criteria can be used for improving the performance of the reconstruction algorithm. Computer simulations show that this method is valid for locating the multi-conductivity distribution in electrical impedance tomography.

Medical Electronic Endoscope (MEE) is a widely used medical instrument. Using the Field Programmable Gate Array (FPGA), we accomplish three parts of work: 1) Optical imaging system. 2) Driving of the Charged Coupled Device (CCD), the function of image data acquisition and display. 3) Based on the dot-array plate arithmetic, a real-time correction system of image distortion via hardware is designed. 4) On the basis of video-servo control method, the system achieves automatic brightness control of electronic endoscope. Finally, a medical electronic endoscope system with a real-time correction system of high-resolution color image distortion is developed.

In this paper a novel method for the chromatic analysis of burn scar is proposed. The aim of the algorithm is to evaluate the curative effect and set up the treatment plan pertinently, because the scar color is an impersonal parameter reflects the degree of scar hypertrophy. The method is based on artificial neural network (ANN) by using photoelectrical technique, and composed of three main parts: firstly capture the digital color images of the burn scar using CCD camera, then change the RGB color data of the burn scar into that of HSB color space and emend it using ANN, lastly judge the degree of burn scar hypertrophy by chromatic analysis using ANN again. The experimental results were good conformed to the degrees of scar hypertrophy given by clinical evaluations. It suggests that the chromatic analysis technique of the burn scar is valuable for further study and apply to the clinical engineering.

The assessment of optic nerve head (ONH) stability in measured short-term increase of intraocular pressure (IOP) in healthy group and initial primary open angle glaucoma (POAG) patients. METHODS: 147 healthy people were divided in two groups according to the age. The first one (59 people) was comprised of those who were from 16 to 35 years old. The second group included 88 healthy adults from 35 to 78. 64 patients (39 - 80 years old) with initial POAG were included in the third group. The mean cup depth (MCD) of the optic disc was determined with the Heidelberg retina tomographer (HRT II). After baseline examination a suction cup was used to increase IOP for 10 mm Hg above baseline and MCD was determined again. IOP level was controlled by Perkins’ tonometer before and during suction. RESULTS: IOP increase always resulted in MCD increase. In group 1 mean increase was 18,3±1,96 μm. In the second group the value was 22,4±2,63 μm. There was no statistically significant difference in MCD mean increase values in groups 1 and 2 (t=1,46, p>0,05). In POAG group mean MCD increase was 49,2±8,41 μm. The difference of this value was statistically significant when compared with that in group 2 (t=5,38, p<0,05). CONCLUSIONS: 1. There was no correlation between age and MCD mean increase in healthy people. 2. Results of the investigation permit us to establish criteria of normal and decreased stability of ONH to the induced elevation of IOP: we consider the MCD increase less than 25 μm as normal, 25 - 40 μm as borderline and more than 40 μm as lack of lamina cribrosa stability.

The ultraviolet light-excitated fluorescence spectra from healthy human blood in vitro have been measured by FLS920 Spectrometer, made in Edinburgh Instruments, exciting light from Xe900 - 450W steady state xenon lamp. The relation between exciting light wavelength and the fluorescence spectral characteristics of blood in the case of certain concentration is provided in this paper. Ultraviolet light excitated healthy human blood fluorescence spectra profiles change in peak intensity and position with exciting light. It may be due to the abruption of large numbers of anisomerous C-C bonds or C-N bonds that absorb the energy by non-resonance on membrane of blood cells, bringing lone-pairs of electrons, forming the new fluorophores and emit fluorescence in the case of later ultraviolet light excitation. It may be why ultraviolet light is able to kill and wound cells. In addition, the fluorescence spectra distributing range is very wide. It is due to contributions of the many fluorophores with large numbers of vibrational energy levels on the ground level in the blood cells. Our understanding of the different wavelength light-induced blood cells fluorescence spectra characteristics may be useful to development of low level laser therapy in vivo and in vitro.

This paper mainly discusses the effective refractive indices of biological tissues and its experimental determination. The implication of effective refractive indices of biological tissues is illustrated and its action on the light transporting in biological tissues is also discussed. After then, an experimental measuring method is proposed to obtain the effective refractive index. Corresponding setup and data processing algorithm are presented in this paper, which is applied to obtain the effective refractive indices of typical samples.

A semi-analytical method has been developed to calculate the spatially resolved diffuse light in layered biological tissues irradiated by converging laser beam based on the diffusion theory. Monte Carlo method is used to evaluate the correctness of the method, results show that they have good consistency and our method has higher computational efficiency. Numerical calculations disclosure same important features that are uniquely related to the propagation of the converging light in biological tissues. Those features are valuable to optimize the optical diagnosis and therapy.

Previous research has shown that un-contact monitoring and characterization of diffuse reflectance photons emerged at the tissue surface could provide the useful physiological parameters within tissue to aid the diagnosis. Generally within this method, the detected optical signal consists of the specular reflection from the tissue surface and diffusive photons emerging from within tissue, while the latter being the signal of interest. However, the surface reflection signal would degrade the signal-to-noise ratio of the system. Therefore, there is a need to eliminate the effect of specular reflection having on the final measurement. In this paper, a simple method using polarization and cross-polarization pair is presented to improve the system SNR by efficiently removing the surface specular reflection. We are expecting that this simple technique could play an important role in the blood glucose measurement with the NIR approach.

Recent progress in optoacoustic tomography has shown its enormous potential in biomedical imaging of biological samples in vivo. The greatest advantage in this imaging modality is that it can offer the imaging contrast comparable to the optical techniques and the imaging resolution similar to the ultrasonic techniques. However, its sectioning capability is largely dependent on the scattering properties of the targeted subject. Therefore, the understanding of how the tissue optical properties affect the imaging performance of optoacoustic tomography would be important. In this paper, we systematically investigate the influence of absorption and scattering coefficients of tissue on the optoacoustic imaging resolution, depth and contrast. In addition, we also investigate the influence of spreading photon diffusion in the tissue on its sectioning capability. In the experiments, tissue phantoms were constructed with a range of optical properties. We used the intralipid solution to control the scattering properties, and the indocynane green to control the absorption property of the phantom. The result shows that the scattering coefficient is a major factor that affects the imaging depth and imaging contrast. It also influences greatly the thickness of tomographic imaging slice due to the light broadening inside tissue caused by the scattering property.

Non-invasive laser-induced photoacoustic tomography is attracting more and more attentions in the biomedical optical imaging field. This imaging modality takes the advantages in that the tomography image has the optical contrast similar to the optical techniques while enjoying the high spatial resolution comparable to the ultrasound. Currently, its biomedical applications are mainly focused on breast cancer diagnosis and small animal imaging. In this paper, we report in detail a photoacoustic tomography experiment system constructed in our laboratory. In our system, a Q-switched ND:YAG pulse laser operated at 532nm with a 10ns pulse width is employed to generate photoacoustic signal. A tissue-mimicking phantom was built to test the system. When imaged, the phantom and detectors were immersed in a water tank to facilitate the acoustic detection. Based on filtered back-projection process of photoacoustic imaging, the two-dimension distribution of optical absorption in tissue phantom was reconstructed.

The investigations of used pulsed Q-switched neodymium:YAG laser induced plasma and shock wave during experimental lenses emulsification were presented. The formation and propagation of plasma and shock wave created by the high powered Nd:YAG laser pulses with a titanium target were imaged through optical multiple analysis, and the pressure of shock wave was calculated. The results of shock wave interacting with the lenses material were observed. The lenses, simulated at different hardness, were placed in containers filled with Ringer's solution. The experimental results are promising and show that the Nd:YAG laser can be used for human lens emulsification.

Protein kinase Cs (PKCs) play an important role in cellular proliferation, and low-energy laser irradiation (LELI) can enhance cellular proliferation. The present work contributes to the understanding of the mechanisms of action by studying effects of LELI at the dose of 0.8 J/cm² on PKCs activities in the single lung adenocarcinoma cell (ASTC-a-1) and in real time by fluorescence resonance energy transfer (FRET) technique. C-kinase activity reporter (CKAR), consisting of a cyan fluorescent protein (CFP), the FHA2 phosphothreonine-binding domain, a PKC substrate sequence, and a yellow fluorescent protein (YFP), was utilized. The living cell imaging showed a decrease in FRET in the cytosol and nucleus after the cells were treated with LELI. These results suggest that PKCs could be activated by LELI throughout the cell, and the proliferation of ASTC-a-1 cells could be modulated by the activated PKCs.

Among the many physiological effects of low-energy laser irradiation, anti-apoptosis functions have been reported. In our experiments A-beta was used to induce cells apoptosis and then the cells were dealt with low-energy laser irradiation (LELI), and finally the LELI effects to apoptosis were detected. The morphology of apoptotic cells was evaluated by fluorescence microscope. The molecular level of apoptosis was detected by quantifying the Bcl-xl mRNA expression using a new highly sensitive and quantitative polymerase chain reaction (QT-PCR) technique. The results show that the Bcl-xl mRNA expression went variety with different treatments to the cells. That indicates that the Bcl-xl is involved in the LELI effect of the Aβ-induced apoptosis.

Caspase8 is activated and cleaves Bid into two fragments when cells are exposed to death-inducing molecules such as tumor necrosis factor-α (TNF-α). Then the C-terminal fragment relocates from cytosol to mitochondria and promotes the release of cytochrome c, in the final cellular apoptosis is induced. Despite recent progress in the study of Bid during apoptosis induction, it remains unclear how C-terminal fragment of Bid cleaved moves to mitochondria and then induces the release of cytochrome c and so on. The 14-3-3 proteins are known to sequester certain pro-apoptotic members of Bcl-2 family. In order to further study the biological action of Bid during apoptosis, especially under physiological condition of living cell, the plasmids pBid-CFP and pYFP-14-3-3 were constructed. By the transient transfection of pBid-CFP and pYFP-14-3-3, the dynamic process of interaction of Bid and 14-3-3 protein in individual living cell during the apoptosis was primarily investigated with FRET (fluorescent resonance energy transfer) technique by the use of fluorescence microscopy.

The detection methods for genetically modified (GM) components in foods have been developed recently. But many of them are complicated and time-consuming; some of them need to use the carcinogenic substance, and can’t avoid false-positive results. In this study, an electrochemiluminescence polymerase chain reaction (ECL-PCR) method for detection GM tobaccos is proposed. The Cauliflower mosaic virus 35S (CaMV35S) promoter was amplified by PCR, Then hybridized with a Ru(bpy)32+ (TBR)-labeled and a biotinylated probe. The hybridization products were captured onto streptavidin-coated paramagnetic beads, and detected by measuring the electrochemiluminescence (ECL) signal of the TBR label. Whether the tobaccos contain GM components was discriminated by detecting the ECL signal of CaMV35S promoter. The experiment results show that the detection limit for CaMV35S promoter is 100 fmol, and the GM components can be clearly identified in GM tobaccos. The ECL-PCR method provide a new means in GMOs detection due to its safety, simplicity and high efficiency.

In this present paper, dry seeds of peanut of cytological effects and agro-character in F₁ generation have been studied for YAG laser-irradiated at 1060 nm. With transmission electron microscope, the effects of ultrastructure of plumule cell were observed. There were difference in the cell on membrane system, fatbody and nucleus, especially in proteinbody, and there was chromosomal aberration of peanut root tip cell induced with laser 35.84w/cm² power density. With irradiating time added from3s to 8s the rate of aberration increased from 0.16% up to 0.53%, and the types of chromosomal aberration also increased. Many aberration types, such as earlier separated mitosis metaphase, variability of number, sticky, non-equal division, polypolarity division, nucleus protrudes to cytoplasm and so on were found in 8s treatment but not in 3s. However, the dose of 8s treatment leads to lethal dose according to the seeds sprouting and growing. The seeds with 3s treatment, mine stem height, total pods per plant, mature pods per plant and weight per plant were more than the seeds unirradiated.

The concentration dependence of the diffusion coefficient of particles suspended in solution depends primarily on the occupied volume fraction and on repulsive and attractive forces. This dependency is expressed by the interaction parameter λ. In the present work we have measured the diffusion coefficient of Bovine Serum Albumin at different ionic strength and determined the interaction parameter. The results indicate: the value of λ is positive at low ionic strength and the interaction between proteins is repulsive; however, with increasing ionic strength the value of λ becomes negative and the interaction is attractive, and when ionic strength is bigger than 0.50M aggregation occurs. The dependence of the interaction on ionic strength is interpreted using DLVO theory for interactions of two hard spheres: with increasing ionic strength, the repulsive electrostatic interaction is screened and Van der Waals forces become dominant. According to the correlation of λ with ionic strength, the protein parameters are regressed: the protein net charge Z_P= -9.0e, Hamaker constant H_A= 2.8k_BT. This work indicates the technique of dynamic light scattering can be used effectively to study protein molecular interactions.

Sonodynamic therapy (SDT) is an effective method for cure tumors, but its mechanism is not clear up to now. In this work, the mechanism of SDT is analyzed by study the reaction between ultrasound and the gallium-porphyrin analogue ATX-70 experimentally. Results show that the ATX-70 is likely to play three roles in SDT. One is that the sonolumiescence (SL) react with ATX-70 directly, the action of ATX-70 is similarly to a sort of photosensitize. The other is that the high temperature produced in the bubbles at collapse makes ATX-70 into excitated states, the excitated ATX-70 react with the dissolved oxygen in liquid and produce oxygen free radicals. The third is that ATX-70 plays a role of surfactant in the process of cavitation and makes the cavitation become easily, lead to more high-energy hydroxide radicals are produced.

A new type pigtail structure with multi-functionality is proposed. The pigtail is imprinted a length of grating or grating module in it, which can act as sensing element for measuring temperature and/or stain around. Two types of sensing element in the structure are given, one is just one length of FBG and another is the FBG module, which is composed of two identical Bragg gratings separated by a cavity along a single fiber, where the cavity is a segment of the fiber that has photo-elastic and/or thermo-optic coefficients different from that of the gratings. The operational principle of the corresponding sensing structure is analyzed in detail. It is demonstrated that by measuring the reflected spectra from the FBG, the temperature and/or stain can be determined. On the other hand, by simply measuring optical power of the reflected light reflected, the temperature or stain can be independently determined.

Ultrasound-modulated optical tomography is a noninvasive imaging technique for biomedical diagnosis. With this technique, an imaging system takes advantage of focused ultrasonic field to mark the photon trajectories in a biological sample by modulating the optical path in the focal zone. The tagged photon reflects the local optical and mechanical properties in the ultrasonic focal zone and permits tomographic imaging of biological tissues by scanning. Based on the high-sensitivity detection technique, we have developed a reflective and coaxial configuration, which was more convenient and hopeful to produce an easy-controlling setup for practical application. In addition, this configuration can bring a new method to improve the spatial resolution of the tomographic plane paralle to the ultrasonic axis in the traditional configuration. Optical tomographys of the biological tissue were successfully obtained experimentally.

The characteristics of ALA absorption spectrum were studied by comparing the difference of ALA absorption spectrum in different conditions in the paper. The results of test show that the wavelength of the strongest absorption spectrum of ALA is 270nm. The relationship between the serum solution density and the absorption peak value is the inverse ratio. The obstructive effect will be more obvious when the density of serum is thicker. The best serum solution density is 10%. The amount of PpIX will be the biggest when the incubate time is suitable and the right time is 8 hours for Jurkat cell.

The characteristics of ALA emission spectrum and excitation spectrum were studied by comparing the difference of ALA emission spectrum and excitation spectrum in different incubation conditions of Jurkat cell in the paper. The results of test show that the wavelength of the strongest emission spectrum of ALA is 375nm. The wavelength of the strongest excitation spectrum of ALA is 255nm and 290nm. The wavelength of 290nm is better to excite the ALA. Those results will be helpful to diagnose and detect the cancer.

Photoacoustic tomography is a potential and noninvasive medical imaging technology. It combines the advantages of pure optic imaging and pure ultrasound imaging. Photoacoustic signals induced by a short pulse laser cover a wide spectral range. We have explored the influences of attenuation of photoacoustic signals, which vary according to frequencies, to the quality of reconstructed photoacoustic images. It reveals that the attenuation of low frequent components are less than that of high frequencies, and the latter is more important for photoacoustic imaging with high resolution. Based on the ultrasonic attenuation theory, the photoacoustic imaging with rectification of the attenuation of different frequent component was performed. The experiments results show that this method improves the resolution of reconstructed images, which improves from 0.3mm to 0.2mm. A Q-switched Nd:YAG laser operating at 1064nm was used as light source. The laser had a pulse width of 6ns and a repetition frequency of 20Hz. A needle PVDF hydrophone with diameter of 1mm was used to detect photoacoustic signals.

In this study a frustrated total internal reflection (FTIR) Q-switched and free-running Er:YAG laser, as well as a novel design transversally excited atmospheric pressure (TEA) oscillator-double amplifier corona preionised high beam quality Hydrogen-Fluoride (HF) laser system, all developed in our lab, were used in dentin ablation experiments. In the case of the Er:YAG laser, pulses of 190 ns in Q-switched operation and of 80 μs pulse width in free-running operation at 2.94 μm were used, while HF laser pulses of 39 ns in the wavelength range of 2.6-3.1 μm in a predominantly TEM₀₀ beam were also used to interact in vitro with dentin tissue. Several samples of freshly extracted human teeth were used, cut longitudinally in facets of 0.4-1.5 mm thick. Ablation experiments were conducted with the laser beam directly focused on the tissue or after being waveguided through suitable mid-IR fiber/waveguide alternatively ended with quartz end-sealing caps. The correlation between the various laser beam parameters, as wavelength, pulse duration, repetition rate, energy and spatial distribution of the beam profile and the ablative characteristics (ablation rates, tissue surface morphology) of dentin surface were investigated.

In this paper, proximity focus x-ray intensifier and corresponding Lixiscope system at home and abroad are introduced. The technical parameters and characteristics are given. The technical ways to improve Lixiscope and the application prospect are offered.

Near-IR spectroscopy holds great promise for non-invasive concentration measurements of blood on the basis of its potential for reagent-less, nondestructive, and noninvasive measurements. The main difficulty for determining absolute or even exact relative concentrations is the scattering behavior of the tissue. This leads to significant differences in the ideal Lambert Beer's law. In this paper, the approach of the Dynamic Spectrum in the frequency domain was proposed by Professor LI Gang etc. is shown, it is based on Photo-plethysmography (PPG) with fast Fourier transforms. The magnitude of fundamental wave of the pulse wave at each wavelength divided by the peak value of the pulse wave, get the natural logarithm of quotient at each wavelength and then the Dynamic Spectrum in the frequency domain is got. Evaluating only the pulsatile part of the entire optical signal, this approach is rather independent of individual or time changes in scattering or absorption characteristics of the tissue. Because of the noise and the resolution of the spectrometer, the Dynamic Spectrum is very difficult to get. In this paper, a series of measures is taken, and high-precision Dynamic Spectrum in the frequency domain is got with the experiment. The approach is verified. The advantage of getting Dynamic Spectrum in the frequency domain is analyzed, and compared with the Dynamic Spectrum in the time domain. The paper shows that the technique enables high precision measurement of changes in tissue absorbance caused by blood pulsation. It is very important in the non-invasive in vivo concentration measurement of blood.

Neuronal growth cones navigate over long distances along specific pathways to find their correct targets. The prevailing opinion is that growth cones appear to be guided by four different mechanisms: contact attraction, chemoattraction, contact repulsion, and chemorepulsion. In contrast to existing methods, we use optical trap to guide neuronal growth. The optical trap is a non-contact manipulation technology which is increasingly used for micromanipulation of living cells and organisms. An intense light gradient near the focal region of a near-infrared laser beam gives rise to forces that make possible optical trapping and manipulation of a variety of micron-sized objects. In the developing nervous system, microtubule and actin play a fundamental role. To change the microtubule polymerization by control the density of tubulins or exerting a persistent force on the whole growth cone, we have shown experimentally that we can use optical trap to guide the growth direction of a neuron. In order to guide the neuronal growth direction, a self-contrived optical trap is placed in front of a specific area of the edge of the cell's growth cone. We turned the neuronal growth direction and guided it to the direction we expected. Control over neuronal growth is a fundamental objective in neuroscience and guiding neuronal growth with optical trap may be very important for the formation of neural circuits as well as nerve regeneration.

As a numerical experiment, Monte Carlo simulation (MCS) has been proven to be a credible and flexible method for predicting the distribution of light in random media. It has full control of many parameters of optical system, which may be cumbersome to obtain in a real experiment. In standard OCT system, confocal microscopy structure with different Numerical Aperture (NA) is selected to acquire superior transverse resolution and unique property of optical sectioning. But the effects of numerical aperture on the probing depth of OCT system are difficult to estimate. In this paper, a new Monte Carlo simulation model of OCT system based on confocal mode is put forward to simulate the confocal microscopy structure and focused gaussian beam. It makes up the deficiency of traditional MCS model, which can only be applied to infinity narrow beam. By applying this new model, the effects of NA on probing depth of OCT system are analyzed, and the estimation of critical probing depth of OCT system is discussed. Study indicates that a smaller numerical aperture has more advantage on the probing depth when the transverse resolution is ensured.

In this study, a novel multilayer-tissue heat transfer model for laser-induced optothermal response is presented by considering the heterogeneous properties of biological tissue. Various temperature measurement techniques for biological tissue under laser irradiation are reviewed. The advantages and limitations of each of these methods are discussed. Based on this, the experimental measurement schemes with a multiple-channel temperature probe for the optical-thermal response of mammalian skin tissue in vitro and in vivo are presented during pulse Er:YAG laser and superpulse CO₂ irradiation. The effect of laser parameters, such as energy density, pulse duration and pulse repetition rate is investigated. Using finite difference method (FDM), the simulation of spatial and temporal distribution of the temperature field inside the biological tissue is investigated during and after pulse laser radiation. Experimental data are fitted and compared to the optical-thermal simulation to test the validation of the model. In addition, the impact factors and uncertainty of the measurement results are discussed. The results we had in this study can be used to predict the temperature rise inside biological tissue under pulse laser irradiation, it is a useful tool for a surgeon to optimize laser parameters before making a therapy plan. It also can predict a temperature rise or thermal damage in interstitial laser thermotherapy.

With the media lighted by linear polarized Laser beam, the backscattering from tissue has been simulated and then analyzed by Monte Carlo Methods. The investigated scattering particles are polystyrene spheres homogeneously dispersed in de-ionized water, which is used as simulating model of tissue-melanoma. This simulation is based on the Mie theory’s spherical scattering particle model and focused on behavior of photons in the backscattering light from the model of tissue. Numerical results having been obtained and compared, conclusions have been made. We theoretically represent the residual polarizing light intensity keeps high when corresponding maximum depth that the photons used to be is shallow, and vice versa. And the distribution of the backscattering’s polarization properties relate regularly to this depth and melanoma can affect them apparently.

Experimental investigation on cerebral damage of adult SD rats induced by 532nm CW laser was performed. Tissue heat conductive equation was set up based on two-layered structure model. Finite difference algorithm was utilized to numerically simulate the temperature distribution in the brain tissue. Allowing for tissue response to temperature variation, free boundary model was used to discuss tissue thermal coagulation formation in brain. Experimental observations show that thermal coagulation and necrosis can be caused due to laser light absorption. The result of the calculation shows that the process of the thermal coagulation of the given mode comprises two stages: fast and slow. At the first stage, necrosis domain grows fast. Then necrosis domain growth becomes slower because of the competition between the heat diffusion into the surrounding undamaged tissue and the heat dissipation caused by blood perfusion. At the center of coagulation area no neuron was observed and at the transitional zone few nervous cells were seen by microscope. The research can provide reference data for developing clinical therapy of some kind of encephalic diseases by using 532nm laser, and for making cerebral infarction models in animal experiment.

This paper reports effects of electrostatic interaction between amino acid and gold colloid on the intensity of surface-enhanced raman scattering (SERS). Near-infrared (NIR) excited SERS has been measured for lysine (Lys) on gold colloid at pH 10.8 and 12.0 where its ε-amino group is ionized and both the α- and ε-amino groups are neutralized, respectively. Note that the SERS intensity changes dramatically with pH. This result suggests that the electrostatic interaction between the positive charge of the ε-NH₃⁺ group and the negative charge of the gold surface is one of the most important factors that determine the intensities of the SERS signals.

This paper reports the near-infrared (NIR) SERS detection of immune reaction on gold colloid particles without bound/Free (B/F) antigen separation. Antibodies or the immune complex are adsorbed on gold colloid particles. Free antigen cannot be adsorbed on the gold colloid particles due to the surface of the gold colloid particles is blocked by bovine serum albumin. Because of the electromagnetic field generated by surface plasmon polariton enhancement, the antibody at 10^-8 M on the gold colloid particles shows intense SERS signals. The same system at 10^-10 M does not give any SERS signal, but Raman bands of antibody again appear upon the formation of immunoglobulin (IgG)-anti-IgG complexes on the gold colloid particles. Free and bound antigen molecules do not yield significant SERS signals since they cannot be adsorbed directly on the gold surface. In this way, one could detect the immune complex on the gold colloid particles by NIR SERS spectroscopy without any B/F antigen separation.

In this paper, laser induced human serum Raman spectra of liver cancer are measured. The spectra differences in serum from normal people and liver disease patients are analyzed. For the typical spectrum of normal serum, there are three sharp Raman peaks and relative intensity of Raman peaks excited by 514.5nm is higher than that excited by 488.0nm. For the Raman spectrum of liver cancer serum there are no peaks or very weak Raman peaks at the same positions. Results from more than two hundred case measurements show that clinical diagnostic accuracy is 92.86%. And then, the liver fibrosis and liver cirrhosis are studied applying the technology of LIF. To liver cirrhosis, the shape of Raman peak is similar to normal and fluorescence spectrum is similar to that of liver cancer from statistic data. The experiment indicates that there is notable fluorescence difference between the abnormal and normal liver tissue and have blue shift in fluorescence peak. Except for human serum, we use rats serum for researching either. Compared with results of path al examination, we analyze the spectra of normal cases, hepatic fibrosis and hepatocirrhosis respectively in an attempt to find some difference between them. Red shift of fluorescence peak is observed with disease evolution using 514.5nm excitation of an Ar-ion laser. However, no distinct changes happen with 488.0nm excitation. These results have important reference values to explore the method of laser spectrum diagnosis.

This paper reports a kind of application of surface-enhanced Raman scattering (SERS) to immunology. In the proposed system, antibody immobilized on a solid substrate reacts with antigen, which binds with another antibody labeled with peroxidase. If this immunocomplex is subjected to reaction with o-phenylenediamine and hydrogenperoxide at 37°C, azoaniline is generated. This azo compound is adsorbed on a silver colloid and only the azo compound gives a strong surface-enhanced resonance Raman (SERRS) spectrum. A linear relationship was observed between the peak intensity of the N=N stretching band and the concentration of antigen, revealing that one can determine the concentration of antigen by the SERRS measurement of the reaction product.

The value of cerebral oxygenation saturation is important for optimal treatment and prognosis in neonates during perinatal period. The purpose of this study was to investigate the cerebral oxygen in newborn infants and obtain clinical characteristic parameters by using steady state spatially resolved near infrared spectroscopy. The subjects consist of 239 infants selected from two hospital. The results show that the values of regional cerebral oxygen saturation (rSO2) for preterm infants with gestational ages of 27 - 32 weeks were different from term infants and the value of rSO2 for sick term infants after treatment were better than that of before treatment. Above results suggest that the value of rSO2 may be used as a clinical parameter to assess cerebral oxygen for preterm and sick infants avoiding hypoxia.

In this paper, a new method of body fat and its distribution testing is proposed based on CT image processing. As it is more sensitive to slight differences in attenuation than standard radiography, CT depicts the soft tissues with better clarity. And body fat has a distinct grayness range compared with its neighboring tissues in a CT image. An effective multi-thresholds image segmentation method based on potential function clustering is used to deal with multiple peaks in the grayness histogram of a CT image. The CT images of abdomens of 14 volunteers with different fatness are processed with the proposed method. Not only can the result of total fat area be got, but also the differentiation of subcutaneous fat from intra-abdominal fat has been identified. The results show the adaptability and stability of the proposed method, which will be a useful tool for diagnosing obesity.

The pulsed dye laser (PDL) has a history of producing safe and effective clearance of dermal vascular lesions; however, non-ablative treatments of rhytids with 595nm PDL are seldom studied. The purpose of our research is to evaluate the changes of skin elasticity, histology and the amount of hydroxyproline after 595nm PDL non-ablative rejuvenation and to offer references for effective clinical treatments. Forty KM mice were used for this experiment. Laser parameters were as follows: an energy fluence of 8 to 12J/cm², a pulse duration of 10ms, and a spot size of 7mm with 10% overlap. Skin elasticity was measured using Reviscometer RVM 600. Specimens were sectioned for hematoxylin-eosin and Van-Gieson staining, and dermal thickness was recorded in an ocular micrometer. The amount of hydroxyproline in the dermis was quantified by the biochemical method. No marked side effects such as blister and purpura were noted during laser treatments. New collagen synthesized with an improvement in the organization of collagen fibrils. The 12 J/cm² group improved skin elasticity by 31.7%, dermal thickness by 25.3% and the amount of hydroxyproline by 55.9%. There were the good correlations between dermal thickness and the amount of hydroxyproline. Therefore 595nm PDL non-ablative photo-rejuvenation is a safe and effective method for wrinkle reduction. And the energy level of 12 J/cm² has the greatest effect in improving skin mechanical properties and accelerating new collagen formation.

Temperature is a long established indicator of health. With the advancement of clinical medicine in thermal disease diagnostics, understanding the thermal life phenomena and temperature behavior has become increasingly important. The biological effects of human exposure to low-intensity laser irradiation thermo-therapy, the best established are those due to elevation of tissue temperature. Bio-heat equations (BHEs) are necessary for predicting tissue temperature during thermal treatment. To prevent harmful levels of heating, restrictions have been proposed on low-intensity laser irradiation as the external spatial heating. In this paper, considering the different properties for the pathological tissue and the normal tissue, using a numerical method to solve the Pennes’ bio-heat equation, we analyzed theoretically the relationship between the temperature distribution and external spatial heating during low-intensity laser irradiation. The effects of the thermal parameters such as the heat conductivity, blood perfusion rate, and metabolic rate of the tissues on the temperature distribution were discussed. The results can be used to predicted different effects on the temperature variation and distribution, the thermal damage distribution and the thermal damage volume etc. The results are also useful in optimizing the therapeutic parameters for improved low-intensity laser irradiation treatments and for better understanding the thermal life phenomena in living tissues.

We examine the optical properties of native and coagulated human liver tissues in vitro at four different wavelengths of argon ion laser, 476.5, 488, 496.5 and 514.5 nm, and the differences in the optical parameters of the tissues between 630nm and 790nm. The optical properties, μ_a, μ_s and g, of liver tissue were determined by measuring the diffuse reflectance, diffuse transmission and collimated transmission in a double integrating sphere set-up, and the inverse adding-doubling algorithm was used to calculate the optical properties from the measurements. The investigative results showed that there were significant differences respectively in the absorption coefficients, scattering coefficients and anisotropy factors between native and coagulated human liver tissues at the same laser wavelength (P<0.01), these large differences of the absolute values in optical properties indicate that there were large differences in compositions and structures between both, and large differences in compositions and structures induce large differences in absorption and scattering properties between both, and these differences vary with a change of laser wavelength. The scattering coefficients for per tissue type exceed the absorption coefficients by at least one order of magnitude. Hence the conclusions may be helpful to diagnostics and therapeutic applications in liver tissue.

The original and deconvoluted spectra of Attenuated Total Reflection (ATR) FTIR have been determined for both benign and malignant tumor tissues samples and the spectral differences have been investigated between the two types of samples. In comparison with the benign samples, the characteristic changes of malignant ones mainly involve: The prominent bands 1652 and 1645cm^-1 due to the proteins in the α-helical and the unordered-random-coils substructures become stronger compared to those in the β-sheet and the turns substructures, suggesting that the former type of proteins increase in content in contrast to the later. The phospodiester band 1083 cm^-1 of the nucleic acids becomes strongest on cancer tissues spectra and its area ratio to the amide II band 1548cm^-1 rises greatly, indicating that the DNA content rises remarkably. The collagen proteins reduce in content while phosphorylated ones rise, and some hydrogen bonding is nearly broken in amino acid residue C-O (H) groups. The glycogen content decreases, and the CH₂ content is higher than CH₃ one. These results suggest that ATR-FTIR spectroscopy has the potential to become a powerful tool for biochemical studies and in vivo diagnosis of human breast cancers.

Clinical application shows that the Q-switched laser therapy on pigmented lesions based on the principle of selective thermolysis is good in efficiency. But the mechanism of this method of treatment remains unclear yet. Elementary researches are up to date restricted to the levels of morphological observation mainly. The beginning split second process within which laser pulse is interaction with dermal tissues has not been investigated in detail. This process also includes a series of sub processes of super high intensity of photo thermotics, plasma shock wave, super express boil inflation, et. Researches of experimental tests to the momentary processes mentioned above have been performed in this project. The results suggest that laser ablation impact and shock wave induced by laser play important rules in the process.

Optical coherence tomography (OCT) is an emerging technology for producing high-resolution cross-sectional imaging based on the principles of low-coherence interferometry. Tissue structure can be imaged on the micron scale in real time. The principle of OCT is analogous to that of ultrasound imaging, except that it measures the intensity of reflected infrared (IR) light rather than sound waves. A new spectral OCT(SOCT) technique is introduced. SOCT and its application to measure depth resolved spectral absorption is described. The crucial parameters of this method like transversal, depth, and spectral resolution and their relations are discussed. In combination with SOCT technique and endoscopes, SOCT enables high-resolution imaging in lumens of, for example, the esophagus and stomach. SOCT can be used to perform 'optical biopsy', or to guide surgery, by providing images in situ and in real time.

Ultrasound modulated optical tomography, a combination of optical and acoustic technology, has become a noninvasive biomedical tomography with promising future. However for long days its spatial resolution was always limited by ultrasound waist size. In this paper a new method using deconvolution algorithm was suggested to solve this problem. Ultrasound modulated optical signals were processed by deconvolution algorithm before they are used for image reconstruction. Both theory analysis and numerical calculation results have shown that the spatial resolution could be greatly improved and image quality became better. This method requires no modification of optical geometry and detection system, only appropriate mathematical processing was needed. It is believed to be a simple, practical and effective way in realizing super resolution in ultrasound modulated optical tomography.

A full discussion on polarized light propagation in turbid media is presented in this paper. A Monte Carlo algorithm was used to simulate the propagation behavior of 2-D Stokes Vectors and Mueller matrices under various conditions. We considered the effect of different incident polarization states, tissue optical parameters and Fresnel matrices at the boundary, and then calculated the backscattered and transmitted Stokes Vectors and Mueller matrices. It is showed that both Stokes Vectors and Mueller matrices are influenced by tissue optical parameters. The regime where we can get clear signals contracts as the scattering coefficient increases. Furthermore, when the boundary effects were added into the calculation, results show good agreement with experimental results reported before, while omitting it leads to great deviation. The simulation also showed that the transmission patterns of Stokes Vectors and Mueller matrices alter in a different way from reflection patterns. Both transmission and reflection patterns can be used to derive tissue information.

An up-converting phosphor technology-based biosensor (UPT-based biosensor) has been developed for immunoassay using Up-converting phosphor (UCP) as the biological marker. The UPT system has realized quantitative detection and has good ability to meet the need of some emergencies. High sensitivity (nanogram/ml), good linear response characteristics and an excellent correlation (R²greater than or equal to 0.95) have been verified by quantitative detection results. The sensitivity of the UPT-based biosensor is better than that of the indirect hemagglutination test in the practical application. All the results are comparable with that obtained by Western Blot detection.

Optical coherence tomography (OCT) is a new imaging modality that is being actively used in a variety of medical applications. Currently, most of the OCT systems operate in the time domain, which requires scanning the optical path length in the reference arm in order to obtain the in-depth profile, i.e. A scan. This however limits the system scanning speed. To avoid the axial scanning and therefore improve the system scanning speed, a novel OCT system is recently proposed by a number of groups that operates in the frequency domain, i.e. the spectral OCT. In this paper, we report the spectral OCT system being constructed at Tianjin University. The system has a dynamic range at 78dB and is capable of scanning speed at 12 seconds per image, largely limited by the bottleneck of data transferring from the CCD camera currently employed to the computer. The SOCT imaging results obtained from the animal tissues (cornea from an intact porcine eye) in vitro will be presented.

Optical coherence tomography (OCT) is a new imaging modality that is being actively used in a variety of medical applications. Optical coherence tomography performs cross sectional imaging by measuring the time delay and magnitude of optical echoes at different transverse positions, essentially by the use of a low coherence interferometry to obtain the depth resolved information of a sample. The interference can occur only when the optical path lengths of light in both the sample arm and reference arm are matched to within the coherence length of light source. The most commonly used light sources in the current OCT systems are the superluminescent diodes (SLD). However, the coherence lengths of SLD are typically 10-30 microns that are not sufficient to achieve the resolution required for many medical applications. In the meantime, the moderate irradiance offered by the SLD limits the real time applications for OCT system, which usually require a power with an order of at least 10 milliwatts. Recently the diode-pumped superfluorescent optical fibers sources has been used in a variety of communication and sensor applications. The superfluorescent rare-earth doped optical fibers source is also the very good OCT systematic light source, because of that have a wide bandwidth of fluorescence and high emission power.

The study of shaping ability is very important in assessment of instruments and preparation techniques. Using simulated canals in these studies have many advantages such as good standardization, good comparability, transparent et al. A new computer assistant measure system particularly designed for quantitative analysis of the shape of simulated canals is set up and described in this paper. This system can be used in automatic assessment of shaping ability of instruments, by image pretreatment, feature extraction, registration, fusion, and measurement. Comparing the simulated root canal shape before and after instrument in the fused image is good to reduce the errors from vision and enhance the repetition of results. The registration and measurement precision of the system can achieve 0.021mm or higher, when the resolution of original root canal image is 1200 DPI or higher. The shaping ability of stainless steel K-files is evaluated by the system.

The aim of this study was to test human erythrocyte deformability with the exposure of erythrocyte from apoplexy patient and other ischemia diseases, contracted with normal donors' blood sample, and the doses-effect of Low-power He_Ne laser in vitro were discussed. Fresh blood sample from adult health donors and patients with different diseases such as apoplexy, diabetes, heart block etc in emergency department were collected and divided into different groups in which there were no less than 6 persons. Fresh human blood samples were irradiated with a He-Ne laser (Lamba=632.8nm), power output around 4.5MW, 9MW, 15mW, and 18mW, et al., exposure time from 7.5min, 15min, and 30min, operating in continuous wave. Measurements of human erythrocyte deformability were taken. Erythrocyte deformability appearance shown some different in the health contracted group and the other ischemia disease group. Some notice difference also shown among some disease group with nonirradiation and the same disease group with laser irradiation. The dose-effects of He-Ne laser therapy was discussed on the further research on the erythrocyte deformability of blood sample from patients with apoplexy disease treated with He-Ne laser at different doses, and a certain optimal doses which could take a beneficial effect in clinic were speculated on. This study revealed that the He-Ne laser have some different effects on erythrocyte deformability in vitro, which were related with the disease condition, red cell state, and outpower-doses, et al closely.

In this paper we introduce a method to increase the axial resolution in optical coherence tomography (OCT) by combining coherence gating with apodization through an appropriate pupil filter. In the proposed probe of our OCT system, the width of the central lobe of the axial point spread function is apodized to be within the coherence length of the light source, while its side-lobes are lying outside without contributing to coherence imaging. It comes to a conclusion that we can obtain improved resolution in OCT system without recurring to broadening the bandwidth of light source, which is nevertheless costing and inconvenient in implementation.

Human prefrontal cortex (PFC) helps mediate working memory (WM), a system that is used for temporary storage and manipulation of information and is involved with many higher-level cognitive functions. Here, we report a functional near-infrared spectroscopy (NIRS) study on the PFC activation caused by verbal WM task. For investigating the effect of memory load on brain activation, we adopted the “n-back” task in which subjects must decide for each present letter whether it matches the letter presented n items back in sequence. 27 subjects (ages 18-24, 13 females) participated in the work. Concentration changes in oxy-Hb (HbO₂), deoxy-Hb (Hb), and total-Hb (HbT) in the subjects’ prefrontal cortex were monitored by a 24-channel functional NIRS imager. The cortical activations and deactivations were found in left ventrolateral PFC and bilateral dorsolateral PFC. As memory load increased, subjects showed poorer behavioral performance as well as monotonically increasing magnitudes of the activations and deactivations in PFC.

A small-animal x-ray micro computed tomography (micro-CT) system has been constructed to screen laboratory small animals and organs. The micro-CT system consists of dual fiber-optic taper-coupled CCD detectors with a field-of-view of 25x50 mm², a microfocus x-ray source, a rotational subject holder. For accurate localization of rotation center, coincidence between the axis of rotation and centre of image was studied by calibration with a polymethylmethacrylate cylinder. Feldkamp’s filtered back-projection cone-beam algorithm is adopted for three-dimensional reconstruction on account of the effective corn-beam angle is 5.67° of the micro-CT system. 200x1024x1024 matrix data of micro-CT is obtained with the magnification of 1.77 and pixel size of 31x31μm². In our reconstruction software, output image size of micro-CT slices data, magnification factor and rotation sample degree can be modified in the condition of different computational efficiency and reconstruction region. The reconstructed image matrix data is processed and visualization by Visualization Toolkit (VTK). Data parallelism of VTK is performed in surface rendering of reconstructed data in order to improve computing speed. Computing time of processing a 512x512x512 matrix datasets is about 1/20 compared with serial program when 30 CPU is used. The voxel size is 54x54x108 μm³. The reconstruction and 3-D visualization images of laboratory rat ear are presented.

In fluorescence correlation spectroscopy (FCS), the fluorescence intensity decay curve is used to calculate the correlation time, which characterizes the diffusion feature of the molecules. However, photobleaching, an unavoidable phenomenon that happened during fluorescence excitation, would result in fluorescence decay, and thus cause error in the calculation of the correlation time and the diffusion coefficient. To compensate this effect, a probability factor is introduced. This factor describes the probability at which a molecule is photobleached by the excitation laser during fluorescence excitation. By selecting the right value of the photobleaching factor, the effect of photobleaching on the FCS measurement can be removed.

Issue of tumor has been a hotspot of current medicine. It is important for tumor research to detect tumors bearing in animal models easily, fast, repetitively and noninvasivly. Many researchers have paid their increasing interests on the detecting. Some contrast agents, such as green fluorescent protein (GFP) and Discosoma red fluorescent protein (Dsred) were applied to enhance image quality. Three main kinds of imaging scheme were adopted to visualize fluorescent protein expressing tumors in vivo. These schemes based on fluorescence stereo microscope, cooled charge-coupled-device (CCD) or camera as imaging set, and laser or mercury lamp as excitation light source. Fluorescence stereo microscope, laser and cooled CCD are expensive to many institutes. The authors set up an inexpensive compact whole-body fluorescent imaging tool, which consisted of a Kodak digital camera (model DC290), fluorescence filters(B and G2;HB Optical, Shenyang, Liaoning, P.R. China) and a mercury 50-W lamp power supply (U-LH50HG;Olympus Optical, Japan) as excitation light source. The EGFP was excited directly by mercury lamp with D455/70 nm band-pass filter and fluorescence was recorded by digital camera with 520nm long-pass filter. By this easy operation tool, the authors imaged, in real time, fluorescent tumors growing in live mice. The imaging system is external and noninvasive. For half a year our experiments suggested the imaging scheme was feasible. Whole-body fluorescence optical imaging for fluorescent expressing tumors in nude mouse is an ideal tool for antitumor, antimetastatic, and antiangiogenesis drug screening.

Fluorescence Correlation Spectroscopy (FCS) is one of the most popular techniques in the studying of intramolecular dynamics as well as molecular interactions of biomolecules in the local microenvironments of cells or tissues. In FCS, fluorescence intensity fluctuations due to Brown movement are measured in a microscopic detection volume defined by a tightly focused laser beam. By fluorescence correlation analysis, a multitude of parameters such as local concentrations & diffuse coefficients are assessed. Combined with high sensitive photoelectric detector, processing circuit and high performance computer, the applications has been reported includes combination of antigen and antibody, micro PH measuring, pharmaceutical drug screening and so on. Particle in light field will be applied a radiation force, especially in two-photon excitation FCS due to its high intensity focused laser beam. This radiation force can be described by two components, i.e. scattering force and gradient force. In this paper, we simulate the two forces of the particle applied in Rayleigh scattering regime, and analyze the radiation force influenced by different radius of the particle.

The goal of this study is to evaluate the feasibility of Near Infrared Spectroscopy (NIRS) as an in vivo monitoring tool for rat breast tumor oxygenation and vascular blood volume by comparison with the established modalities, magnetic resonance imaging/spectroscopy (MRI/MRS). The changes in oxygenated hemoglobin concentration and total hemoglobin concentration (Δ[HbO₂], Δ[Hb]_total) with respect to hyperoxic gas interventions were monitored by NIRS. Changes in deoxygenated hemoglobin, a blood oxygenation level dependent (BOLD) contrast, and blood volume on breast tumors were monitored by BOLD MRI and ¹⁹F MRS of PFOB, respectively. Results showed strong consistency among the two pairs: Δ[HbO₂] versus BOLD signal, Δ[Hb]_total versus tumor blood volume. These consistent results demonstrated the ability of NIRS as a valid in-vivo real time monitoring tool for studying the dynamic responses of Δ[HbO₂] and Δ[Hb]_total to therapeutic interventions applied to rat breast tumors. Furthermore, the results suggested that NIRS and MRS are complimentary with each other in terms of temporal and spatial resolutions.

Since Roentgen discovered x-ray and performed the first x-ray imaging more than 100 years ago, x-ray imaging has always been based on the biological tissue's differences in x-ray attenuation. However, x-ray-tissue interaction causes x-ray phase changes as well, and the tissue’s differences in phase are about one thousand times larger than their differences in x-ray attenuation. We will present the theoretical foundation and design considerations for clinical x-ray phase-contrast imaging systems based on the x-ray in-line holography. Different from the analysis in literature, we proposed a new formalism for in-line phase-contrast imaging to analyze the effects of four clinically important factors on the phase-contrast. These are the body parts attenuation, the spatial coherence of incident x-ray from an x-ray tube, polychromatic x-ray and radiation dose to patients for clinical applications. We will discuss the phase image-reconstruction based on our new theory for the x-ray in-line holography as well. The theory and image reconstruction algorithms presented in this paper can be applied widely to the diagnostic x-ray imaging applications. The phase-contrast imaging system design guidelines based on the new theory will be discussed and its validation by the computer simulations will be demonstrated.

The fluorescent spectra of human blood with different concentration induced by different wavelength LED light are reported in this paper. The phenomenon that fluorescence peaks are apparently red-shifted with the increase of blood concentration is analyzed and the mechanism is given a reasonable explanation. The results indicate that the peak is shifted following the rule of e-exponent with the increase of the blood concentration. The mechanism of different energy transfer with different fluorescent areas is analyzed from the theory of energy transfer. The resonance energy transfer is the primary reason of the fluorescent spectra peaks. The concept of the idea fluorescence and the inner fluorescence is also brought forward in this paper. The research will give refer intrinsic fluorescence diagnostic techniques of organic tissue.

Cell culture using bioreactors is a vital part of Cellular and Tissue Engineering. Bioreactor design continues to advance, in order to allow control over physical and chemical parameters as well as continuous assessment of cell behaviour, gene expression, and tissue formation and growth. Measurement or monitoring of many such parameters or features can be achieved with optical techniques. The current aim of cell culture is to re-create in vivo conditions and in order to achieve this control of the chemical environment is required and some cell types must be subjected to shear stress and/or axial loads. For creating tissue engineered cartilage chondrocytes are cultured within a biodegradable scaffold. Influences of cyclic loading and of oxygen supply on phenotype are studied. Vascular endothelial cells are subjected to fluid shear stress and the influence on prostacyclin production is measured. Optical interrogation of culture fluid, attached cells, cells in suspension and tissue constructs is carried out using a combination of spectrophotometry, analysis of scattering, and chemical sensing. Insertion of sensing probes within the culture vessel presents problems of protein adsorption to sensing surfaces. Approaches based on cell membrane mimicry are being evaluated for their potential to overcome this problem. Sensors based on immobilised fluorophores and chromaphores within either wall-mounted membranes or within optical fibres are assessed. Culture fluid turbidity is evaluated with scattering determinations and circulating glucose concentration is measured spectrophotometrically. Formed tissue is interrogated with NIR radiation and in the future will include the use of OCT.