• Journal of Sensor Science and Technology
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• v.12 no.5
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• pp.225-230
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• 2003

Nowadays, laserthermia is widely used to treat malignant tumors with generating heat as the one of minimal invasive surgeries. Generally, the laserthermia probe system consists of the fiber-optic laser and light guides, image guide and temperature sensor. It is very important to measure the temperature of treating tumor and make a stable temperature ($42{\sim}43^{\circ}C$) during the treating time. Therefore, laserthermia probe needs temperature sensor which can measure it exactly and fast. In this study, to develop a new type of temperature sensor with LC(liquid crystal) and optical fiber, the reflectivity of LC according to the temperature changes are measured. Also, the relationships are derived from the results.

• Progress in Medical Physics
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• v.14 no.2
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• pp.99-107
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• 2003

This study was performed to prepare the verification film for localizing beam-target position with the Photon Knife radiosurgery system (PKRS) using linear accelerator(Mitsubishi, Model ML-15MDX). We developed a laser calibration system using a reticle of transparent lucite to detect Inlet and outlet beams. We verified fixation of the second collimator with film mounted on a holder in the shape of an octagon block 5cm apart from the isocenter. The film was exposed to photon beams of linear accelerator at an interval of 45 degrees during the gantry movement. There were no shifts in the beam of the second collimator during gantry movement. We used a position marker which is designed a head-shaped small lead block and a 10 mm in diameter of steel bead in the plastic tube. The position marker helped to verify the beam directions with patient position in multi-arc and trans-multi-arc of PKRS The verification of beam alignments showed an average 0.8$\pm$0.26 mm discrepancy in LINAC-gram images of PKRS. In our study, the couch movement was $\pm$5 mm laterally, while it shook $\pm$ 2 mm toward the couch axis. The couch, however, was immediately returned to the initial site after shaking. Thus, we postulate that the beam-target position(s) should be verified with LINAC-gram in a stereotactic radiosurgery system to achieve the accuracy of beam-target alignment.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.15-24
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• 2003

The purpose of this study is to investigate the sterilization effect of Er:YAG laser against the intraoral acid producing bacterium, S. mutans, by irradiating the culture solution containing S. mutans KCTC 3065 with Er:YAG laser having a $650{\mu}m$ diameter beam through the non-contact method. We obtained the following results after examining the temperature changes of the culture solution, numbers of bacterial colonies, and acid-producing ability and attaching ability on teeth by measuring the amount of extracellular polysaccharide produced by S. mutans. The number of bacterial colony was decreased in $10{\mu}l$ culture solution irradiated with laser in overall compared to the control solution. The number decreased as the irradiation intensity and pulse repetition rate were larger and as the exposure time was increased. However, it did not change significantly in $100{\mu}l$ culture solution compared to the control solution. Although the acid-producing ability of S. mutans was inhibited for a certain duration after laser irradiation in 10r1 bacterial culture solution, it did not change in $100{\mu}m$ solution compared with the control solution. The amount of extracellular polysaccharide synthesized by S. mutans was partially decreased through laser irradiation in $10{\mu}m$ culture solution but did not change in $100{\mu}m$ culture solution. Based on these findings, we concluded that Er:YAG laser has an sterilization effect on S. mutans in which we presume that the mechanism is through the heat effect rather than the mechanical effect from development of ultrasound.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.22 no.1
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• pp.30-33
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• 2011

Laser is a relatively recent addition to laryngeal surgery. Since their invention, laser use and applications have expanded rapidly. The use of lasers in surgery has offered a time- and cost-efficient alternative to cold surgical techniques and has been used in the treatment of numerous laryngeal pathologies, including stenoses, recurrent respiratory papillomatosis, leukoplakia, nodules, malignant laryngeal disease, and polypoid degeneration (Reinke's edema). Despite the notable benefits, laser surgery is not without disadvantages. Laser heat can increase scarring and cause damage to adjacent tissue. With laser laryngeal microsurgery, there is potential for airway fire, endolaryngeal bleeding, perichondritis, chondritis, granuloma, surgical emphysema, laryngeal stenosis and web formation, postoperative edema and swallowing problem. Surgeons should be known about these complications and could manage properly.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.21 no.2
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• pp.112-120
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• 2010

Transoral $CO_2$ laser microsurgery has been widely used for various laryngeal diseases. Laser cordectomy for the management of early laryngeal carcinoma has advantages with regards to oncologic results, preservation of laryngeal functions, morbidity and cost in comparison to those of open surgery or radiation therapy. $CO_2$ laser is also applicable to benign vocal fold lesions such as nodules, polyps, cysts, reinke's edema, granulomas, papillomas, hemangiomas and glottis webs. $CO_2$ laser is suitable for microsurgery because it has small focus size and hemostatic effect. We should also recognize the risks of $CO_2$ laser for safe use.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.29 no.2
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• pp.76-78
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• 2018

With recent developments in medical technology and the introduction of various types of lasers, the role of fiberoptic laryngeal laser surgery (FLS) in laryngology has been significantly expanded. FLS are typically performed under local anesthesia, and patients may return to normal activities immediately after the procedure. This corresponds to the current trend of minimally invasive surgery and may limit unnecessary general anesthesia, reduce medical costs, and increase patient compliances. Main indications of FLS procedure were vocal polyp, recurrent respiratory papillomatosis, vocal fold granuloma and vocal fold dysplasia. In this review, we discuss practical tips and unique value of FLS.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.2
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• pp.117-122
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• 2016

Purpose: Gingival whitening is one of dental treatment purposes which is close to treating aesthetic disorders. Initial gingival whitening treatment was done by dermabrasion using a high power Diode Laser. However, this treatment method cannot be free from any infection or pain after the treatment. Therefore, we have decided to progress gingival whitening treatment using a low power LED laser. Materials and Methods: The laser was irradiated on pork meat then the safety of output power, temperature change and skin denaturalization was measured. Bison 365 nm LED laser was irradiated on oral mucosal pigment of a 15 - 20 kg beagle for 15 min for 1 - 2 weeks, one or two times each. Any pigment loss was checked through Hematoxyline-Eosin staining. Results: The melanin pigments at the area of 365 nm LED Laser irradiation were decreased. Conclusion: The 365 nm LED Laser proposed in this study is considered to compensate the bleaching effect achieved by either using Diode laser or surgical methods.

• 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 Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.24 no.2
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• pp.102-106
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• 2013

The cure rates for early stage laryngeal cancer are similar between laser cordectomy and radiation therapy. As well as the survival outcome, one of the main measures of success in treatment of early laryngeal cancer is voice outcome. Many studies have demonstrated that laser cordectomy and radiation therapy to be equivalent with regard to vocal outcome, whereas others favor radiation. Although such as somewhat disadvantages of voice outcome, laser cordectomy still remains a valid option. Since the patients who treated with laser may benefit from additional phonosurgery to improve postoperative vocal outcome. In this article, we reviewed the techniques of phonosurgery which can be used for laryngeal reconstruction after laser cordectomy. The indications for using each technique are discussed, with particular attention paid to functional outcomes following these reconstructive efforts.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.563-567
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• 2009

This study compared the instrument performance and tissue healing of a steel scalpel with a $CO_2$ laser in an animal uterine surgery model. Five Landrace and Yorkshire mixed breed pigs were used. Two symmetrical incisions were made in the uterine of each pig. One incision was made on the left side of the uterine horn using a steel scalpel, while the other incision was performed on the right side using a $CO_2$ laser with an 8W output power. Each instrument was evaluated clinically for speed, ease of incision, and extent of bleeding. An ovariohysterectomy was performed at 21 days after the surgical procedure for a histological examination. The scalpel was an easier instrument to use in the confines of the uterine tissue, compared with the laser. However, there is no significant difference between the two groups. The amount of bleeding was less in the laser group but the time of the incisions was shorter with the scalpel. Postoperative uterus adhesion in the $CO_2$ laser incisions was lower than the scalpel incisions. Scalpel incisions showed complete restoration of the epithelium and endometrial gland. On the other hand, the laser incisions showed incomplete restoration of the epithelium and endometrial gland. Although the scalpel produced less damage to the uterine tissue and was easier to handle than the $CO_2$ laser, it did not provide hemostasis that was helpful for use on highly vascular tissue. The $CO_2$ laser provided good hemostasis but delayed wound healing.