Near-infrared photoimmunotherapy (NIR-PIT) is an emerging cancer therapy based on conjugating monoclonal antibody (mAb) with a NIR phthalocyanine dye conjugate. Direct tumor necrosis and immunogenic cell death occur during NIR irradiation. We applied a multi-modal optical imaging approach including high-resolution optical coherence tomography (OCT) and high-sensitivity fluorescence mesoscopic tomography, to provide 3D tumor micro-structure and micro-distribution of mAb-IR700 in the tumor simultaneously during and after NIR-PIT in situ and in vivo. Moreover, label-free speckle variance algorithm combined OCT was applied to monitor the change of blood vessels and the alterations of the blood volume inside the blood vessels during and NIR-PIT treatment.
Background: Acute tubular necrosis (ATN) after renal ischemia-reperfusion would cause the loss of functional units in the kidney, that are usually used to characterize the activity of the kidney. Apparently, ATN will lead to uneven distribution of uriniferous tubules. The renal activity could be evaluated by analyzing the uniformity of renal tubular distribution. Methods: Optical coherence tomography (OCT) has been proved to have the ability of imaging the microstructure of kidney in vivo and in real time. Based on the renal ischemia-reperfusion model of Wistar rats described in previous studies, kidneys of three Wistar rats were ischemia for 75 minutes and reperfused for one and a half hour. The normal kidney before ischemia and every 5 minutes after blood reperfusion were imaged using a SDOCT system in 3D mode in vivo. Inhomogeneous distribution of tubules could be clearly observed in the en face OCT images of kidney after blood reperfusion. Box dimension based on fractal theory can be used to evaluate the uniformity of object distribution. This paper applied box dimension to assess the uniformity of renal tubular distribution in OCT images of kidney. The fractal dimension of en face OCT images at the same depth below the renal capsule were calculated using Fractal box count toolbox in ImageJ. Results: The results showed that the box dimensions of OCT kidney images changed a lot at different times of ischemia-reperfusion process. The value was largest for normal kidney, and reached a minimum when ischemia, then gradually increased to a stable value after reperfusion. Therefore, the fractal box dimension value could be applied to assess the status of kidney. Conclusion: The renal tubular uniformity featured by fractal box dimension of OCT images could be used to evaluate the renal ischemia - reperfusion injury.
Background: Liver cancer is a leading cause of cancer mortality in China. Early diagnosis and treatment play a significant role in reducing liver cancer mortality. Aims: In this preliminary study, the feasibility of using surface enhanced Raman spectroscopy (SERS) of serum to identify primary liver cancer was explored. Materials and methods: Serum samples were obtained from liver cancer patients (n = 25) and healthy controls (n = 30). Nano-silver (Ag) colloids (45 ± 6 nm) were used as the SERS substrate and mixed with serum samples (10 μL). Raman spectra were obtained from a confocal Raman micro-spectrometer (Renishaw) and spectral characteristics analyzed. Results: Analyses of spectral characteristics showed noticeable differences in peak heights between the mean spectra of the control and patients, mainly reflected in following peak positions: increased at 496, 593, 637, 726, 813, 888, and 1137 cm-1, and decreased at 1580 cm-1, respectively. Which might be attributable to glycogen, phosphatidylinositol, aminoacid methionine, C-S (protein), C-C stretching, methylene rocking, palmitic acid and C-C stretching, respectively. Conclusion: These preliminary analyses suggest that SERS might be useful for the identification of serum markers of liver cancer.
Optical coherence tomography (OCT) is a useful non-invasive optical tool for imaging various biological tissues. As OCT imaging is based on interferometry, speckle noises are inherent and can degrade the quality of OCT image. The objective of this study was to evaluate the effectiveness of conventional denoising algorithms for OCT image denoising and for improving image quality. OCT images of human skin were obtained from a swept source OCT of 1300 nm. Three image denoising algorithms, including median filtering, mean filtering and Gaussian bilateral filtering, were applied for denoising OCT images of different quality. Five quality evaluation criteria, including signal to noise ratio (SNR), equivalent number of looks (ENL), contrast-to-noise ratio (CNR), cross correlation (XCOR), and peak signal to noise ratio (PSNR) were used for comparing the effectiveness of each denoising process. In terms of improving local contrast, three denoising algorithms showed similar effect. In terms of the equivalent views, Gaussian bilateral filtering algorithm showed the most significant increase and therefore caused certain degrees of blurry. For signal to noise ratio, all three denoising algorithms showed improvement while Gaussian bilateral filtering algorithm had better protection effect of the effective information and edge of the original image. Gaussian bilateral filtering algorithm provides better denoising outcomes for OCT image processing.
Optical properties of biological tissue are key parameters of optical imaging, and also provide useful information of the tissues under different physiological conditions. The optical attenuation coefficient (OAC) related to the optical properties can be calculated from optical coherence tomography(OCT) data. OCT has the advantages of high-resolution and fast imaging speed, and can image the tissues in vivo and in real-time. Due to the lack of blood perfusion, renal ischemia is accompanied by changes in microstructure of the kidney, which the OAC is sensitive to. We applied OCT to detect the OAC variation during ischemia-reperfusion process of rabbit kidney, and further estimated the ischemiareperfusion (I/R) injury. In order to study the temporal relationship between I/R injury and ischemia, 12 New Zealand rabbits were divided averagely into 4 groups (ischemia 30/60/90/120 min group). The kidneys were observed in vivo using a spectral domain OCT (SD-OCT) which light source centered at 900 nm. Three-dimensional OCT images of the kidney were obtained before the occlusion of renal artery and several time points after the blood reperfusion. The OAC were obtained by exponential fitting of OCT A-lines. Mapping attenuation coefficient (MAC) of each 3D OCT data set was performed to get the attenuation coefficient distribution in the kidney. The OAC curve with reperfusion time showed that the OAC was sensitive to ischemia and helpful for the estimation of ischemia-reperfusion injury. The distribution of attenuation coefficient in MAC image could reflect the local status of kidney.
Renal artery occlusion is an unavoidable process during operations such as nephrectomy, carcinoma resection, kidney transplantation and so on. For minimizing the kidney injury, the optimal renal ischemia time was experimentally investigated. Optical coherence tomography (OCT) is a high resolution imaging modality can non-invasively image biotissue in vivo and in real time. In order to study the relationship between tubular injury and the renal ischemia time, OCT images of Wistar rat kidneys endured various ischemia time were obtained throughout the whole ischemia-reperfusion procedure. The tubular density and the average diameter of uriniferous tubules were considered as biomarker of kidney activity, and the quantitative results well described the degree of kidney injury.
Optical coherence tomography (OCT) technology can be used to obtain high resolution cross sectional image of living biological tissues. Early study suggested that some tissue optical properties could also be measured using OCT. In this study, OCT was used to measure the total attenuation coefficient of living kidney of rat and dog models. Results suggested that the total attenuation coefficient of the superficial cortex layer could by derived from a single scattering model. The total attenuation coefficient could be affected by ischemia.
Optical coherence tomography (OCT) is an imaging technology which can be used to obtain the high resolution cross sectional image of living biological tissues. It has been used to evaluate the structure and function of animal and human kidneys. Preliminary animal and human data suggest that OCT imaging might be a useful non-invasive tool for characterizing renal tubular lumens, such as the opening status of tubular lumens. In this pilot study, living animal kidneys (dog, rat and mouse) were imaged using a swept source OCT (SS OCT) or spectral domain OCT(SD OCT). In vivo imaging scans were carried out using an OCT microscope setup (5×) and by placing the imaging probe above the surface of the living kidney. Semi-quantitative analysis of the OCT images was performed to evaluate the density of the kidney tubules on the surface layer of the cortex. In addition, histological images of the kidneys were restructured to form nephron three-dimensional structure for comparison with the 3D OCT imaging. This study suggests that quantitative OCT imaging might be useful for visualizing the fine structure of the living kidney and determining the density of renal tubules.
Optical coherence tomography (OCT) is a useful optical biopsy tool. Its potential in the evaluation of living kidney has been demonstrated. One of such applications is to predict the acute tubular necrosis (ATN) associated with kidney transplantation. The light dense and lucent regions seen in 2D OCT scanning are considered as a useful marker of the renal tubules. In this study, the OCT examination of living human kidney was carried out using a swept source (SS) OCT (SS-OCT) system. The light lucent regions in the cortex obtained on the OCT scan were defined as low signal cavities. The structure features of characteristic cavities in 2D and simulated 3D OCT images were quantitatively analyzed using Amira and Matlab programs. Although the imaging acquisition and real-time analysis were feasible for the examination of donor kidney before and after the transplantation, as the imaging acquisition was obtained under the hand-hold fashion, OCT images might become blurred and the tubules became hardly distinguishable from cortex background, especially for 3D images. In order to optimize the scanning parameters of the OCT imaging process, the influence of the jittering of the living kidney on the quality of OCT imaging and the distortion of the renal tubule structure were studied.
The objective of this laboratory study was to evaluate the use of a swept-source optical coherence tomography (SS-OCT) as a diagnostic tool for dental caries. The carious molars were extracted from human volunteers and examined visually using conventional dental equipment without any magnification. SS-OCT observations were carried out on the same sites as where the conventional examination had been performed. The center wavelength of SS-OCT system is 1300 nm at a 100 kHz sweep rate. The results showed that SS-OCT could clearly create cross-sectional imaging of dental structures. Moreover, carious lesions could be detected and distinguished from normal tissues. In conclusion, the SS-OCT signal could be used as a marker for early caries detection.
The technologies based on Differential Interference Contrast microscopy (DIC), Laser Scanning Confocal Microscopy
(LSCM), Two Photon Emission Laser Scanning Microscopy (TPELSM) and Optical Coherent Tomography (OCT) were
used to study the changes of mouse skin after irradiated by Intense Pulse Light (IPL). The experimental results were
compared and analyzed by different microscopic observation tools. The relations of the epithelial or dermal interaction
with IPL in different energy density were given, and the morphologic changes of mouse skin were observed before and
after days irradiated respectively. The function of dermal collagen during the renovating of the tissue and the key factors
were presented.
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