• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.514-517
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• 2002

We developed Frequency-shifted feedback laser using AOM inside the cavity. The feedback loop of the laser is formed with the first-order diffracted light of the AOM to output mirror. It is shown that the FSF laser output has spectral output called“chirped frequency comb”with an ultrafast frequency chirp rate of several hundreds of PHz/s. It can know the range using chirped frequency comb in the optical range measurement that is FSF laser as source.

• Korean Journal of Bronchoesophagology
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• v.17 no.1
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• pp.29-34
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• 2011

Traditionally, the main strategy of treatment of the head and neck cancer was en bloc resection including adjacent normal tissues through wide incision. However, the procedures may leave severe functional deficit such as swallowing difficulty, aspiration, and wide neck scar. Therefore, many attempts have been made up to minimize these morbidities. Of them, the minimal invasive approach such as transoral laser microsurgery (TLM) and transoral robot surgery (TORS) have been spolighted as a sensible strategy for organ preservation of the head and neck cancer patients. Results of TLM are equivalent to those obtained by conventional surgery, with considerably less morbidity, less hospital time and better postoperative function. Oncologic results of TLM are equivalent to conventional surgery. TORS are safe, feasible, and promising but oncologic safety is not yet verified. This article covers to current application of TLM and TORS, their advantages and limitations, and future direction.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.5
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• pp.431-435
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• 2009

The apparatus has been fabricated using the laser diode and microprocessor unit. The apparatus used a InGaAlP laser diode for laser medical therapy and was designed for a pulse width modulation type to increase stimulation effects. To raise the stimulus effect of the human body, the optical irradiation frequency could be set up. The study has executed in-vivo experiment by employing our own developed laser diode irradiation system to investigate the effects of the InGaAlP laser diode irradiation on the wound healing as a preliminary study aimed at the application of InGaAlP laser diode to wound healing of human skin injury. The study cut out whole skin layers of Sprague-Dawley rat on the back part in 1 cm circle and observed developing effects after executing light irradiation for 9 days, and in result it is found that the light irradiation rat showed earlier wound healing than non-irradiation rat during the experimental period. In addition, there are some differences found regarding the healing process between laser diode irradiated rats and non-irradiated ones.

• Biomedical Science Letters
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• v.15 no.1
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• pp.87-91
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• 2009

In photodynamic therapy (PDT), oxygen plays important role. Because of singlet oxygen which is produced by activated photosensitizer after laser irradiation of specific wavelength. The aim of this study is to find how oxygen concentration affects anticancer effect in PDT. Groups were divided into PDT with oxygen applied group and only PDT applied group. PDT with oxygen applied group supplied oxygen for 15 minute before laser irradiation. In vitro, CT-26 cell was incubated with various concentration of photofrin $(50.0{\sim}0.05{\mu}g/ml)$ and was irradiated with 632nm diode laser 6hr after application of photofrin. The cell viability of two groups was assessed by MTT assay. In vivo, CT-26 cell line was transplanted into the subcutaneous tissue of BALB/c mouse. The anticancer effect of two groups was measured by tumor volume change. In vitro study, the cell viability was significantly decreased at $1.56{\sim}3.13{\mu}g/ml$ in PDT with oxygen applied group. In vivo study, the PDT with oxygen applied group significantly higher reduction rate of tumor volume 7 days after PDT compared to PDT only group. The high oxygen concentration might enhance the anticancer effect of the photodynamic therapy.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.192-196
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• 1996

[ $1.06/1.32{\mu}m$ ] dual-wavelength medical laser was developed and preliminary clinical comparisons at these two wavelengths were performed for dental application. We could develop a compact laser system 1) by lasing two wavelengths from the same Nd:YAG rod, and 2) by introducing high-voltage switching power supply modules. Experiment on gingiva of pig jaw showed higher thermal damage at $1.32{\mu}m$. Depending on particular procedures, each wavelength has its own advantages and disadvantages. For cutting, however, using conical tips rather than bare fibers provided better results with low threshold of cutting energy and less surrounding thermal damage. Appling light-absorbing dye on target area appeared to induce more damage during laser irradiation. However, histological studies showed no significant difference whether dye was applied or not.

• Medical Lasers
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• v.9 no.1
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• pp.12-24
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• 2020

Human fibroblast-derived multi-peptide factors (MPFs) have been used during treatments with energy-delivering modalities to enhance energy-induced tissue reactions. Human fibroblast-derived MPFs, which include a range of growth factors and chemoattractive factors, activate and recruit fibroblasts and endothelial cells, as well as promote extracellular matrix deposition, all of which are crucial to wound repair. Interestingly, fibroblasts from different species or anatomical sites exhibit distinct transcriptional properties with high heterogeneity. In addition, the patterns of MPF secretion can differ under a range of experimental conditions. Therefore, the use of allogeneic fibroblasts and proper cultivation thereof are necessary to obtain MPFs that can enhance the epithelial-mesenchymal interactions during wound repair. Moreover, energy-delivering devices should be selected according to evidence demonstrating their therapeutic efficacy and safety on a pathological skin condition and the major target skin layers. This paper reviewed the histologic patterns of post-treatment tissue reactions elicited by several energy sources, including non-ablative and ablative fractional lasers, intense focused ultrasound, non-invasive and invasive radiofrequency, picosecond-domain lasers, and argon and nitrogen plasma. The possible role of the immediate application of human fibroblast-derived MPFs during wound repair was proposed.

• Journal of the Korean Applied Science and Technology
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• v.23 no.1
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• pp.70-76
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• 2006

The influence of fluorophor, scatterer, absorber in turbid materials by light scattering were interpreted for the scattered fluorescence intensity and wavelength, it is studied the molecular property by laser induced fluorescence spectroscopy. It can be found that the effects of optical property are penentrated in scattering media by the optical $parameters({\mu}s$, ${\mu}a$, ${\mu}t$, ${\gamma}$, ${\rho})$. The value of scattering coefficient ${\mu}s$ is large appeared by means of the increasing particles of scattering, it can be found that the slope appears exponentially as a function of distance from laser source to detector. It may also utilize in designing the best model for oil chemistry, laser medicine and application of medical engineering.

• Medical Lasers
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• v.9 no.1
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• pp.1-5
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• 2020

Hearing organs have unique characteristics and have a role in processing external sensory signals. Sensory hair cells and nerve fibers in the organ of Corti can be damaged by various causes and they do not regenerate themselves. Medication used for clinical treatment for the inner ear is limited due to the anatomical structure of the inner ear. Photobiomodulation (PBM) is a therapeutic approach that uses various sources of light and the success of PBM therapy is highly reliant on the parameters of the light sources. The positive effects of PBM have been reported in various clinical fields. This paper summarizes the previously reported research on PBM for the treatment of hearing damage in animal models.

• Korean Journal of Acupuncture
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• v.29 no.1
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• pp.17-22
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• 2012

Objectives : The purpose of this study is to discuss the diagnostic classification of the traditional medicine for pilosis, and the hair removal treatments in traditional medicine and its clinical application. Backgrounds : In recent years, appearance and beauty have become main interest that have positioned in the medical area. In clinical Korean medicine, a variety of methods such as moxibustion, superficial bleeding, multiple microneedling, facial meridian massage, herbal medicine facial pack, laser acupuncture, and intense pulsed light (IPL) have been applied. Methods and Results : Pilosis, a condition of abnormal hair growth, is stated for the first time in the publication, [Pathogenesis and Manifestations of All Diseases] by Chao Yuan-fang in 610 A.D. It shows that pilosis has been recognised as a disease for ages in Asia. Reviewing several publications, we found multiple approaches to pilosis were already existed in korean medicine. They include internal medicinal classification and its' medications. Acupuncture treatments also focused on regulation of radical causes and superficial removal of abnormal hairs. Specific treatments includes body and ear acupuncture, ear acupressure, hypodermic acupuncture, hypodermic acupuncture injection, laser acupuncture treatment. Physical and chemical methods of hair removal were widely invented. we resulted that significant scientific approaches to pilosis are under way in the korean medical field, and found a variety of medical treatments such as herbal medicines and dermatological methods. Conclusions : Hair removal treatments for pilosis in traditional medicine has a long history. Combined with advanced modern technology it can achieve greater advance in cosmetology.

• Medical Lasers
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• v.10 no.3
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• pp.146-152
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• 2021

Background and Objectives Although lasers have been widely applied in tissue treatment, the light penetration depth in tissues is limited by the tissue turbidity and affected by its absorption and scattering characteristics. This study investigated the effect of using an optical clearing agent (OCA) on tissue to improve the therapeutic effect of 1064 nm wavelength laser light by reducing the heat generated on the skin surface and increasing the penetration depth. Materials and Methods A diode laser (λ = 1064 nm) was applied to a porcine specimen with and without OCA to investigate the penetration depth of the laser light and temperature distribution. A numerical simulation using the finite element method was performed to investigate the temperature distribution of the specimen compared to ex-vivo experiments using a thermocouple and double-integrating sphere to measure the temperature profile and optical properties of the tissue, respectively. Results Simulation results showed a decrease in tissue surface temperature with increased penetration depth when the OCA was applied. Furthermore, both absorption and scattering coefficients decreased with the application of OCA. In ex-vivo experiments, temperatures decreased for the tissue surface and the fat layer with the OCA, but not for the muscle layer. Conclusion The use of an OCA may be helpful for reducing surface heat generation and enhance the light penetration depth in various near-infrared laser treatments.