• Journal of the Korea Computer Industry Society
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• v.2 no.4
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• pp.565-572
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• 2001

At the most recent years, laser medical instruments, laser applications and laser nuclear fusion need strong visible light and ultraviolet rays. Nonlinear optical devices, such as harmonic generators and parametric oscillators, provide a means of extending the frequency range of available laser sources. Frequency conversion is a useful technique for extending the utility of high-power lasers. It utilizes the nonlinear optical response of an optical medium in intense radiation fields to generate new frequencies. These progresses have been used to generate high-power radiation in all spectral regions, from the ultraviolet to the far infrared. Optical parametric oscillators and amplifiers generate two waves of lower frequency They are capable of generating a range of wavelengths from a single frequency source, in some cases spanning the entire visible and near infrared regions. Consequently, in order to obtain the green light, the pulsed Nd:YAG laser using multiple-mesh PFN(Pulsed Forming Network) method with Nonlinear optical device was adopted. We compared the current pulseshapes with the laser output energy, and conversion efficiency.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.5 no.1
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• pp.64-68
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• 1994

Anterior glottic webs shorten the free margins of the vocal cords and prevent air flow at their locations, thereby changing the potential vibratory characteristics of the vocal system. They are now more often iatrogenic from endolaryngeal surgical procedures, complications of intubation, chronic inflammation or due to penetrating and blunt trauma to the larynx. A wide range of treatment procedures are now available but the solution to acquiring a "normal" voice has remained elusive due to reflectory stenosis and scar formation. We present our recent experiences with glottic web in nine cases using KTP-532 laser vaporization and endolaryngeal silastic keel insertion technique. Postoperative speech assessment in our cases showed significant improvement in voice quality of 7 of 9 cases studied(77.8%), and no specific problems were not seen.

• Medical Lasers
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• v.9 no.2
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• pp.126-133
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• 2020

Recurrent respiratory papillomatosis (RRP) is a benign tumor that occurs in the respiratory tract, especially in the larynx. The etiology of RRP is human papillomavirus (HPV). According to the age of occurrence, RRP is divided into childhood-onset and adult-onset types. Generally, childhood-onset RRP shows a high recurrence rate and diffuse involvement in the respiratory tract. Adult-onset RRP is more localized and appears more frequently as a solitary lesion. It may be the result of sexual transmission or the proliferation of latent HPV infections. At present, the treatment of choice for RRP is CO₂ laser ablation. In addition, pulse dye laser or KTP (KTiOPO: potassium-titanyl-phosphate) lasers are also used. Non-surgical adjuvant therapies can be applied in cases requiring repetitive surgery or with diffuse extensions. This review will introduce the clinical features of RRP and various treatment options including lasers.

• Korean Journal of Head & Neck Oncology
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• v.14 no.2
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• pp.164-168
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• 1998

Background: Supraglottis and glottis have a different embryologic origin. Supraglottic cancer is characterized by high incidence of cervical lymph node metastasis at initial diagnosis, and favored surgical management of the early supraglottic cancer was partial supraglottic laryngectomy, however the procedure resulted in frequent incidences of postsurgical aspiration and voice disabilities. Objectives: We retrospectively analyzed the problems and the advantages of the endoscopic laser assisted supraglottic partial laryngectomy as a part of surgical management for early supraglottic cancer. Materials and Methods: During the past nine years 25 cases of supraglottic cancer(Tl 10 cases, T2 15 cases) were treated by tracheotomy and laser assisted supraglottic partial laryngectomy(KTP532, 15 Watt, continuous type) and in 10 cases with cervical lymph node metastasis, they were additionally managed by neck dissection one week later, and all cases received postoperative irradiation therapy. Results: At present, 19 cases are alive with no evidence of disease. During the follow up period total of six cases(primary failure: three cases, nodal failure: three cases) were recurred. In relation to tumor staging, One of the 10 Tl cases and two of the 15 T2 cases recurred showing 88% locoregional recurrence rate for early supraglottic cancer. Postoperative com-plication included bleeding in three cases who were controlled by electrocautery under general anesthsia, one case of longstanding aspiration and two cases of laryngeal stenosis as a delayed complication. Conclusion: High control rate suggests that the endoscopic laser assisted supraglottic partial laryngectomy may be a good initial management method for early supraglottic cancer, however it is difficult to determine the resection margin, therefore, accurate tumor staging must be done prior to surgery. In order to prepare for postoperative bleeding, edema and aspiration, the tracheotomy must be performed prior to surgery.

• Korean Journal of Optics and Photonics
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• v.14 no.1
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• pp.85-91
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• 2003

Intracavity frequency doubling of a single-mode Nd:YAG laser by using a nonplanar ring cavity is demonstrated. The nonplanar ring cavity consists of a Brewster-angled Nd:YAG crystal placed in a magnetic field, a KTP crystal, and two spherical mirrors. In this design the Nd:YAG block acts as both a nonreciprocal polarization rotator and a partial polarizer, and the nonplanar portion of the ring cavity, which is formed by a relative twist angle between the Brewster-angled end surfaces of the Nd:YAG block, serves as a reciprocal polarization rotator. An eigenpolarization theory for the cavity configuration is presented and suitable values of the relative twist angle for unidirectional operation are estimated. A single-mode output power of 22 ㎽ at 532 nm and an optical to optical conversion efficiency of 1.8% are obtained with a 1.2 W diode laser at 809 nm.

• 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.

• Korean Journal of Head & Neck Oncology
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• v.12 no.2
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• pp.201-205
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• 1996

Early detection of glottic cancer, facilitated by rigid telescopes or flexible fiberoptic laryngoscope in addition to sparse true vocal cord lymphatics, makes this a highly curable tumor in its early stage. Early glottic cancer has a high cure rate with only radiotherapy or conservative surgery. However complications such as mucositis with radiotherapy and voice complications with conservative surgery has raised recent interest in endolaryngeal laser cordectomy. Laser cordectomy can preserve phonatory function and avoid the complications such as mucositis of radiotherapy. To determine the effectiveness of laser cordectomy, the authors made a two year retrospective study of 23 early glottic cancer cases. Fourteen cases(60.9%) who underwent 1 to 3 endoscopic laser cordectomy with KTP-532 laser were cured with this procedure alone. Seven cases needed an additional radiotherapy and three cases needed therapy with salvage operation. We conclude that the endoscopic laser surgery is a good strategy for the properly selected glottic cancer.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.29 no.4
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• pp.14-23
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• 2016

Objectives : One of major complications of diabetes, diabetic ulcer is also one of the main reasons for amputation, and the prevalence rate is 4-10%. Laser therapy is widely used for leg ulcer and diabetic ulcer, and it is known to improve wound epithelialization, cellular content, and collagen deposition. The purpose of this study is to investigate the properties of the laser and the spectrum of laser instruments for diabetic ulcer. Methods : We performed literature search using the PubMed, Cochrane, CINAHL and Web of science for the data in English. In addition, other databases were checked for different languages such as OASIS and NDSL for the literature in Korean, CNKI in Chinese, and CiNii and J-STAGE written in Japanese. We excluded all review article and experimental studies, and only clinical studies using laser or light emitting diode (LED) for diabetic ulcer were selected. Results : A total twenty papers were selected. Different light sources were used as follows: LED, HeNe, InGaAlP, GaAlAs, GaAs, CO2, and KTP. The number of LED studies was 9, and HeNe laser was 7, and InGaAlP and GaAlAs laser was 2, GaAs, CO2, and KTP laser was 1 for each. Various energy density of the clinical study were reported. Conclusions : It is suggested that to select appropriate laser type and give the adequate output power to treat diabetic ulcer. Further evaluation and research for the condition of laser therapy to treat diabetic ulcers are warranted.