An imaging system was developed based on single-channel and transparent rotating deflector (TRD) to achieve stereoscopic video imaging. To acquire images at high frame rate, a CMOS camera was used with triggering function allowing image acquisition at certain time point. Stepping motor was controlled to rotate in an arc, stopping at the edge for image acquisition. The acquired 2D images were displayed in stereoscopic 3D using active shutter glasses and conventional display monitor. Using microcontroller (MCU) as centralized control system, system components were controlled and synchronized through using general purpose input/output (GPIO) ports. The created system was evaluated for two factors: motor rotation analysis based on MCU signal generation; and image property based on coefficient of variation calculation.
Methodologies to fabricate a solid optical tissue phantom (OTP) mimicking epidermal thin-layer have been developed
for in vitro human skin experiment. However, there are cumbersome and time-consuming efforts in fabrication process
such as a custom-made casting and calculation of solvent volume before curing process. In a previous study, we
introduced a new methodology based on spin coating method (SCM) which is utilized to fabricate a thin-layer OTP
analogous to epidermal thickness. In this study, a double layer solid OTP which has epidermal and dermal layers was
fabricated to mimic the morphological and optical similarity of human tissue. The structural characteristic and optical
properties of fabricated double layer OTP were measured using optical coherence tomography and inverse adding
doubling algorithms, respectively. It is expected that the new methodology based on the SCM may be usefully used in
the fabrication of double layer OTP.
Skin erythema has been widely used as a diagnostic parameter in dermatology. This study describes a methodology for real-time measurement of skin erythema variation induced by negative compression. This study developed an optical measurement probe, which includes a RGB color sensor that translates in the vertical direction, with the magnitude of vertical translation dependening on the amount of skin deformation. Real-time measurement of erythema variation as a function of both negative compression and time was performed in vivo on 10 measurement sites located on the back of each of 12 volunteers who participated in this study. Negative compression was sequentially applied from −30 to −80 kPa and continuously at a constant magnitude (−80 kPa ) condition. The results showed that skin erythema was uniformly induced at the measurement sites and linearly increased as a function of both negative compression and time. A wide range of individual variation was noted for skin erythema, which may be due to variations in anisotropic skin properties between volunteers. This study demonstrated the clinical feasibility of a novel optical device for skin erythema measurement. Future studies are needed to investigate the clinical applications of this device.
Recently, tissue optical clearing (TOC) has been considered as a useful tool in low level laser therapy due to the
enhancement of photon density in deep tissue layer. In this study, glycerol injection, tissue temperature, laser pulse
modulation, and their combination methods were investigated and compared by analyzing 2D and 3D laser beam profile.
A thermal plate was built to control tissue temperature from 40°C through 10°C at 10°C decrement. A continuous laser
of 660 nm was modulated at the frequencies of 1, 10, 25, and 50 Hz. 95% glycerol was injected into a region of interest
of sample where laser is irradiated and its effect was analyzed after 5 min. Finally, their combination method was
evaluated. Analysis was performed with the diffusion images acquired by CCD and the optical properties measured by
double integrating sphere. Results demonstrated that average peak intensity of laser beam profile was 1) 1.57-fold higher
at 10°C than 40°C, 2) 1.79-fold higher at 10 Hz than continuous wave, 3) 1.65-fold higher with 95% glycerol injection
than no glycerol application, and 4) 2.52-fold higher at the combination method than independent methods. Average total
intensity at FWHM was 1) 1.44-fold higher with tissue cooling, 2) 1.71-fold higher at 10 Hz, 3) 1.61-fold higher with
glycerol injection, and 4) 2.19-fold higher with the combination method. In conclusion, this study implies that tissuecooling,
pulse modulation, glycerol injection, and their combination method can effectively deliver laser photon in LLLT
by enhancing the photon density in soft tissue.
Noninvasive low-level laser devices have been introduced for therapeutic purpose in medicine. However, low-level laser
cannot deliver enough photon density to expect positive therapeutic results in deep tissue layer due to light scattering
property in tissue. In order to overcome the limitation, this study was aimed to develop a negative pressure applied low-level
laser probe to enhance laser transmission and, therefore, photon density in soft tissue. In order to evaluate clinical
feasibility of developed laser probe, ex-vivo experiments were performed with porcine skin samples and laser
transmissions were quantitatively measured as a function of tissue compression. The laser probe has an air suction hole
to apply negative pressure to skin, a transparent plastic body to observe tissue deformation, and a small metallic optical
fiber guide to support the optical fiber when negative pressure was applied. By applying negative pressure to the laser
probe, the porcine skin under the fiber guide is compressed down and, low-level laser is emitted into the skin. Diffusion
images of laser in the skin samples were acquired with a CCD camera and analyzed. Compared to the intensity without compression, the peak intensity of laser beam profiles increased about 2~2.5 times and FWHM (Full Width at Half Maximum) decreased about 1.67~2.85 times. In addition, the peak intensity was linearly increased as a function of
compression. In conclusion, we verified the enhancement of laser transmission and therefore, photon density in tissue by
applying negative pressure to the developed low-level laser probe and its potential for clinical usefulness.
Over the last two decades, optical polarimetry method has been applied for glucose concentration monitoring in biological media such as aqueous humor and cell culture media as a non-invasive alternative method. Compared to glucose analyzer and electronic analyte sensor, the advantages of polaimetry method are non-ionizing radiation to interrogate the sample, non-interference with the sample, needless of consumable reagents, use of readily available sources, and prospect of miniaturizing the optics. Commercial polarimeter is widely used to measure the concentration of chemical compounds with optical activity. However, this device was based on off-line measurement so that it needs sample extraction process to measure the concentration of sample. This process does not reflect the real-time status of sample concentration and sample contamination can be occurred during sample extraction when applied to cell culture process. In polarimetry method, the measurement sensitivity can be controlled by varying optical path length. However, in current polarimeter, the sample cell should be exchanged to vary the optical path length. This process is a time consuming and might cause sample contamination in cell culture process. Therefore, it is necessary to develop a new polarimetry method which can measure the real-time status of sample concentration without sample extraction. In this paper, we introduce a new polarimetry probe system which might be utilized to monitor glucose concentration during cell culture process. It was designed to have variable optical path lengths to control the optical rotation angle of polarized light. We describe the feasibility of the system and the preliminary results.
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