• Korean Journal of Bronchoesophagology
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• v.2 no.2
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• pp.194-199
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• 1996

Laser therapy is becoming an accepted procedure for tissue coagulation and ablation and is especially useful in treating tumors. The laser energy is applied to the tissue of interest through various delivery systems which are introduced percutaneously, via blood vessels, through body openings, or during surgical exposure of the tissue. One of the major obstacles to effective application of lasers has been the lack of reliable method to determine the extent of tissue involvement in real time. Several methods have been proposed for monitoring the tissue response and controlling the laser in real time during laser therapy. Among them, magnetic resonance imaging(MRI) has been introduced to monitor laser-tissue interactions because laser irradiation induces changes not only in the thermal motions of the hydrogen protons within the tissue but also in the distribution and mobility of water and lipids. The buttocks of New Zealand rabbits were treated by KTP and $CO_2$laser(power : 10 watts, exposure time:10 seconds). m images were taken at immediately after lasering, 1 week later, 2 weeks later, and at the same time, tissues were harvested for histopathologic study. We analyzed MR images and histopathologic findigs of laser-treated tissues. The MR images taken immediately after laser treatment showed 3 layer pattern and which was correlated with histopathologic changes. We suggest MRI may become a useful monitoring tools for laser-tissue interaction.

• Journal of the Korean Society of Visualization
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• v.8 no.4
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• pp.54-59
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• 2010

A laser moxibustion therapy device having effect similar to that of traditional moxibustion is being developed using 1064 nm infrared laser. The therapy device allows direct interaction of laser light with the tissue rendering temperature distribution both on the skin surface and deep under the skin. We made a device that could measure temperature of deep under the surface of agar gel tissue phantom using thermocouples. A thermal imaging camera was used to verify results from the temperature measurement device. We compared the characteristics of heat transfer inside the tissue phantom during moxibustion and laser irradiation. The temperature distribution measured by thermocouples was found to be similar to that of distribution given by thermal imaging camera.

• Journal of the Optical Society of Korea
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• v.13 no.3
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• pp.321-329
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• 2009

Following their applications in cardiology, ophthalmology and dentistry among others, the advent of lasers in dermatology and urology had become the success story of the past decade. Laser-assisted treatments in dermatology and urology are mainly based on the laser-induced tissue injury/coagulation and/or ablation, depending upon the desirable clinical endpoint. In this review, we discussed the underlying mechanisms of the laser induced tissue ablation. In any medical laser application, the controlled thermal injury and coagulation, and the extent of ablation, if required, are critical. The laser thermal mechanism of injury is intricately related to the selective absorption of light and its exposure duration, similarly to the laser induced ablation. The laser ablation mechanisms were categorized into four different categories (the photo-thermally induced ablation, the photo-mechanically induced ablation, the plasma induced ablation and the photoablation) and their fundamentals are herein described. The brief history of laser treatment modality in dermatology and urology are summarized.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.375-379
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• 1997

Pulsed Er:YAG and $CO_2$ lasers induced temperature rise of tissue are studied using axisymmetric, two-dimensional, and transient Pennes' bio-heat equation or the implications of skin resurfacing. Model results indicate that Er:YAG laser induced temperature has much higher but more shallow distribution in tissue than that of the $CO_2$ laser because of its higher absorption coefficient. The increase of repetition rate does not affect the temperature rise too much because these laser modalities have much shorter heat diffusion time than the temporal length of each off-pulse. This model works as a tool to understand the photothermal effect in the laser-tissue interaction.

• Journal of Photoscience
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• v.5 no.1
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• pp.39-43
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• 1998

Pulsed Er: YAG and CO$_2$ lasers induced temperature rise of tissue is studied using axisymmetric, two-dimensional, and transient Pennes bio-heat equation for elucidating the implications of skin resurfacing. Modeling indicates that Er:YAG laser induced temperature has much higher but more shallow distribution in tissue than that of the CO$_2$ laser because of much higher absorption coefficient. The increase of repetition rate does not much affect on temperature rise because these laser modalities have much shorter heat diffusion time than the temporal length of each off-pulse. This model works as a tool to understand the photothermal effect in the laser-tissue interaction.

• Medical Lasers
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• v.10 no.2
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• pp.76-81
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• 2021

Biological tissues and organs are composed of different arrays of cells, biochemical cues, and extracellular matrices arranged in a complex microarchitecture. Laser-Assisted Bioprinting (LAB) is an emerging and promising technology that is reproducible with high accuracy that can be used for fabricating complex bioengineered scaffolds that mimic tissues and organs. The LAB process allows researchers to print intricate structural scaffolds using cells and different biomaterials essential for facilitating cell-scaffold interaction and to induce tissue and organ regeneration which cannot be achieved in a traditional scaffold fabrication. This process can fabricate artificial cell niches or architecture without affecting cellular viability and material integrity. This review tackles the basic principles and key aspects of Laser-Assisted Bioprinting. Recent advances, limitations, and future perspectives are also discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.9
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• pp.807-814
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• 2013

A fundamental study on laser-tissue interaction was conducted with the aim of developing a therapeutic medical device that can remove lesions on the intestinal wall by irradiating a high-power 808-nm infrared laser light incorporated in an endoscopic system. The perforation depth was linearly increased in the range of 1~4 mm in proportional to laser output (3~12 W) and irradiation time (5~20 s). We demonstrated that the perforation depth during laser irradiation was varied according to the tissue property of each extracted porcine organ. The measurement of the temperature distribution suggests that the energy is localized in the irradiation spot and transferred to deep tissue, which protects the surrounding tissue from thermal injury. These results can be used to set the driving parameters for a laser incision technique as an alternative to conventional surgical interventions.

• Journal of the Optical Society of Korea
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• v.17 no.2
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• pp.205-212
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• 2013

Pain is one of the quite common symptoms in clinics and many treatment methods have been applied to relieve pain. Among the treatments, high-intensity light therapy for pain has been introduced, but this therapy has not been fully supported by confirmed efficacy due to the absence of quantitative assessments and treatment feedback data in real time. In this study, the evaluation of light distribution in tissue was performed with current high-intensity light sources quantitatively using light-tissue interaction simulations. The diffuse reflectance in tissue was generated using Monte Carlo simulation that traces photons as they undergo multiple scattering and absorption within each tissue layer (skin, fat, and muscle) and within multi-layered tissue. The results showed that the highest diffuse reflectance and the deepest penetration of tissue were achieved at ${\lambda}$=830 nm when compared with other wavelengths like ${\lambda}$=650 nm, 980 nm and 1064 nm.

• Progress in Medical Physics
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• v.6 no.1
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• pp.19-37
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• 1995

The use of lasers in medicine has opened up entirely new fields of therapy and diagnosis. The process in biotechnical applications of laser is basically different from traditional one in other technical field because of critical account to the human body. This paper surveys the principle of biomedical applications as well as possible future developments in laser medicine. In particular, the following subjects are extensively presented : 1) laser-tissue interaction, 2) therapeutic, and diagnostic technique, 3) laser op tical fiber for medicine, and 4) laser safety.

• Korean Journal of Acupuncture
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• v.22 no.2
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• pp.163-181
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• 2005

Objective: The purpose of this study is to review research papers on low level laser therapy (LLLT) and to improve the knowledge of LLLT field. Methods: For introduction, laser characteristics, including wavelength, medium, beam size, power, and unit power were explained. In order to understand LLLT, tissue optics and light-biomatter interaction were briefly mentioned. We reviewed 21 Korean papers on laser acupuncture and LLLT on the viewpoint of laser apparatus. Results and Conclusion: We found that the description of laser apparatus employed for LLLT experiments were not fully written. Laser wavelength and power which are the most crucial parameters, were omitted in several papers. No paper had information on beam size. In order to have high efficacy, laser should be used with proper laser parameters. Conditions of irradiation area or acupoints should be considered too. Some future technology on laser acupuncture were mentioned.