In clinical diagnosis, subcutaneous vein detection may be a useful method to investigate the morphological information of skin and to perform intravenous injection. Although an enhanced image may provide more effective information than a bare eye, medical doctors may feel uncomfortness due to the visual offset between the images displayed on the monitor and the actual target. This study was aimed to develop a projection based real-time subcutaneous vein detection imaging modality (PSVDIM) and to evaluate its feasibility in optical tissue phantom (OTP) and human. Projection-based technology allows users to intuitively know the size and location of the region of interest. The PSVDIM consists of a Near Infrared (NIR) camera and eight NIR LEDs, and laboratory built program based on MATLAB . The images acquired with or without PSVDIM were compared to evaluate the performance of PSVDIM. With the PSVDIM, it was possible to find blood vessels that were not clearly distinguished by bare eye.
Although the patients with cancer on pancreas or pancreaticobiliary duct have been increased, it is very difficult to detect and to treat the pancreatic cancer because of its low accessibility and obtuseness. The pancreatic cancer has been diagnosed using ultrasonography, blood test, CT, endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasonography (EUS) and etc. Normally, light can be delivered to the target by optical fibers through the ERCP or EUS. Diffusing optical fibers have been developed with various methods. However, many of them have mechanical and biological problems in the use of small-bend-radius apparatus or in tissue area. This study developed a therapeutic cylindrical diffusing optical fiber probe (CDOFP) for ERCP and EUS which has moderate flexibility and solidity to treat the cancer on pancreaticobiliary duct or pancreas. The CDOFP consists of a biocompatible Teflon tube and multimode glass fiber which has diffusing area processed with laser and high refractive index resin. The CDOFP was characterized to investigate the clinical feasibility and other applications of light therapy using diffusing optical fiber. The results presented that the CDOFP may be used in clinic by combining with endoscopic method, such as ERCP or EUS, to treat cancer on pancreas and pancreaticobiliary duct.
This study introduces a single-channel optical video stereomicroscope based on a transparent rotating deflector (TRD) for high-resolution and high-magnification stereomicroscopy. The existing stereomicroscopes have some limitations, such as limited resolution and magnification, fixed optical channel, and the necessity to use higher quality and higher cost optical channel components compared with the conventional optical microscopes. The goal of this study was to develop a method for improved stereo imaging and stereovision for optical microscopy. Here, we demonstrate the generation of stereo video images of left and right pairs by the refraction of light passing through a motorized TRD. We estimated the corresponding rotation angles for human stereovision and the required torque. In addition, we evaluated the image quality stability under the TRD rotation.
Although numerous studies have been performed to fabricate various optical tissue phantom (OTP) models, the fabrication of OTPs that simulate skin layers is laborious and time-consuming owing to the intricate characteristics of skin tissue. This study presents various OTP models that optically and structurally simulate the epidermis–dermis skin layer. The spin-coating method was employed to reproduce a uniform thin layer that mimics the epidermis layer, and the fabrication parameters were optimized for epoxy and silicone reference materials. Various OTP models simulating blood vessels and hyperpigmentation lesions were fabricated using the two reference materials to determine their feasibility. The suitability of each of the two reference materials for OTP fabrication was qualitatively evaluated by comparing the quality of the OTP models.
A stereoscopic imaging modality was developed for the application of ophthalmology surgical microscopes. A previous study has already introduced a single-channel stereoscopic video imaging modality based on a transparent rotating deflector (SSVIM-TRD), in which two different view angles, image disparity, are generated by imaging through a transparent rotating deflector (TRD) mounted on a stepping motor and is placed in a lens system. In this case, the image disparity is a function of the refractive index and the rotation angle of TRD. Real-time single-channel stereoscopic ophthalmology microscope (SSOM) based on the TRD is improved by real-time controlling and programming, imaging speed, and illumination method. Image quality assessments were performed to investigate images quality and stability during the TRD operation. Results presented little significant difference in image quality in terms of stability of structural similarity (SSIM). A subjective analysis was performed with 15 blinded observers to evaluate the depth perception improvement and presented significant improvement in the depth perception capability. Along with all evaluation results, preliminary results of rabbit eye imaging presented that the SSOM could be utilized as an ophthalmic operating microscopes to overcome some of the limitations of conventional ones.
As the interest in skin was increased, number of studies on skin care also have been increased. The reduction of skin
density is one of the symptoms of skin aging. It reduces elasticity of skin and becomes the reason of wrinkle formation.
Low level laser therapy (LLLT) has been suggested as one of the effective therapeutic methods for skin aging as in
hasten to change skin density. This study presents the effect of a minimally invasive laser needle system (MILNS)
(wavelength: 660nm, power: 20mW) in skin density. Rabbits were divided into three groups. Group 1 didn't receive any
laser stimulation as a control group. Group 2 and 3 as test groups were exposed to MILNS with energy of 8J and 6J on
rabbits' dorsal side once a week, respectively. Skin density of rabbits was measured every 12 hours by using an
ultrasound skin scanner.
Tibial defect is very common musculoskeletal disorder which makes patient painful and uncomfortable. Many studies
about bone regeneration tried to figure out fast bone healing on early phase. It is already known that low level laser
therapy (LLLT) is very convenient and good for beginning of bone disorder. However, light scattering and absorption
obstruct musculoskeletal therapy which need optimal photon energy delivery. This study has used an interstitial laser
probe (ILP) to overcome the limitations of light penetration depth and scattering. Animals (mouse, C57BL/6) were
divided into three groups: laser treated test group 1 (660 nm; power 10 mW; total energy 5 J) and test group 2 (660 nm;
power 20 mW; total energy 10 J); and untreated control group. All animals were taken surgical operation to make tibial
defect on right crest of tibia. The test groups were treated every 48 hours with ILP. Bone volume and X-ray attenuation
coefficient were measured on 0, 14th and 28th day with u-CT after treatment and were used to evaluate effect of LLLT.
Results show that bone volume of test groups has been improved more than control group. X-ray attenuation coefficients
of each groups have slightly different. The results suggest that LLLT combined with ILP may affect on early phase of
bone regeneration and may be used in various musculoskeletal disease in deep tissue layer.
Stereoscopic retinal image can effectively help doctors. Most of stereo imaging surgical microscopes are based on dual optical channels and benefit from dual cameras in which left and right cameras capture corresponding left and right eye views. This study developed a single-channel stereoscopic retinal imaging modality based on a transparent rotating deflector (TRD). Two different viewing angles are generated by imaging through the TRD which is mounted on a motor synchronized with a camera and is placed in single optical channel. Because of the function of objective lens in the imaging modality which generate stereo-image from an object at its focal point, and according to eye structure, the optical set up of the imaging modality can compatible for retinal imaging when the cornea and eye lens are engaged in objective lens.
This study investigates the feasibility of an endoscopic laser speckle imaging modality (ELSIM) in the measurement of perfusion of flowing fluid in optical bone tissue phantom(OBTP). Many studies suggested that the change of cochlear blood flow was correlated with auditory disorder. Cochlear microcirculation occurs under the 200μm thickness bone which is the part of the internal structure of the temporal bone. Concern has been raised regarding of getting correct optical signal from hard tissue. In order to determine the possibility of the measurement of cochlear blood flow under bone tissue using the ELSIM, optical tissue phantom (OTP) mimicking optical properties of temporal bone was applied.
This paper introduces a stereoscopic video imaging modality based on a transparent rotating deflector (TRD). Sequential two-dimensional (2D) left and right images were obtained by rotating the TRD on a stepping motor synchronized with a complementary metal-oxide semiconductor camera, and the components of the imaging modality were controlled through general purpose input/output ports using a microcontroller unit. In this research, live stereoscopic videos were visualized on a personal computer by both active shutter 3D and passive polarization 3D methods. The imaging modality was characterized by evaluating the stereoscopic video image generation, rotation characteristics of the TRD. The level of 3D conception was estimated in terms of simplified human stereovision. The results show that singlechannel stereoscopic video imaging modality has the potential to become an economical compact stereoscopic device as the system components are amenable to miniaturization; and could be applied in a wide variety of fields.
Fabrication of optical tissue phantom (OTP) simulating whole skin structure has been regarded as laborious and time consuming work. This study fabricated multilayer OTP optically and structurally simulating epidermis-dermis structure including blood vessel. Spin coating method was used to produce thin layer mimicking epidermal layer, then optimized for reference epoxy and silicone matrix. Adequacy of both materials in phantom fabrication was considered by comparison the fabrication results. In addition similarities between OTP and biological tissue in optical property and thickness was measured to evaluate this fabrication process.
Although the mechanism of low level laser therapy (LLLT) is unclear, many studies demonstrated the positive clinical performance of LLLT for skin rejuvenation. An increase in dermal collagen plays an important role in skin rejuvenation and wound healing. This study aimed to investigate collagen generation after interstitial low level laser stimulation (ILLS). Rabbits were divided into two groups: surfacing irradiation and minimally invasive irradiation. 660nm diode laser of 20mW with 10J, 13J and 15J was applied to the backside of rabbits. Collagen formation was evaluated with ultrasound skin scanner every 12 hours. Results shows that ILLS groups have denser collagen density than surfacing groups.
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.
Arthritis is a chronic inflammatory disease that induces potentially damaging and commonly disabling. Various imaging modalities have been used for the evaluation of arthritis. This study aimed to investigate the feasibility of laser speckle contrast image (LSCI) in the evaluation of the severity and early stage of arthritis in animal model. Arthritis was induced on mouse foot and evaluated by a trained expert and the LSCI. The arthritis severity was quantitatively evaluated by speckle index (SI) computed from LSCI. In visual inspection by an expert, it was difficult to evaluate the arthritis because there was no noticeable different between control mouse group (CMG) and arthritis mouse group (AMG) in erythema. However, arthritis was easily evaluated by significant SI different between the CMG and AMG. In addition, the LSCI also successfully evaluated the early stage of arthritis, presenting different SI distribution depending on lesion.
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.
Solid optical tissue phantoms (OTPs) have been widely used for many purposes. This study introduces a spin-coating method (SCM) to fabricate a thin-layer solid OTP (TSOTP) with epidermal thickness. TSOTPs are fabricated by controlling the spin speed (250 to 2500 rpm), absorber concentration (0.2% to 1.0%), and the number of layers. The results show that the thicknesses of the TSOTPs are homogeneous in the region of interest. The one-layer TSOTP achieves maximum and minimum thicknesses of 65±0.28 μm (250 rpm) and 5.1±0.17 μm (2500 rpm), respectively, decreasing exponentially as a function of the spin speed. The thicknesses of the multilayer TSOTPs increases as a function of the number of layers and are correlated strongly with the spin speed (R 2 ≥0.95 ). The concentration of the OTP mixture does not directly affect the thickness of the TSOTP; however, the absorption coefficients exponentially increase as a function of absorber concentration (R 2 ≥0.98 ). These results suggest that the SCM can be used to fabricate homogeneous TSOTPs with various thicknesses by controlling the spin speed and number of layers. Finally, a double-layer OTP that combines epidermal TSOTP and dermal OTP is manufactured as a preliminary study to investigate the practical feasibility of TSOTPs.
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