• 대한두경부종양학회지
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• 제18권1호
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• pp.36-40
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• 2002

Background and Objectives: To determine if laser endoscopic microsurgery is a reliable and appropriate approach in the treatment of laryngeal carcinomas. Materials and Methods: Retrospective study of 62 patients treated with CO2 laser from June 1988 to November 2000 at Seoul National University Hospital for laryngeal squamous cell carcinoma. All patients were treated with curative intention. Fifty three untreated patients with laryngeal carcinoma (39 glottic and 14 supraglottic carcinoma patients) had primary carbon dioxide laser microsurgery. Nine radiation failure patients were treated. Postoperative radiotheray was done for 17 patients. Neck dissection was performed simultaneously for 4 supraglottic cases with cervical nodal metastasis. Mean follow-up duration was 40 months. Results: In primary laser surgery group, distribution of tumors (American Joint Committee on Cancer, 1997) were 38 cases with Tl, 13 cases with T2, 2 cases with T3. Cure rate was 88.7%(47/53) and local control rate was 92.5%(49/53). Larynx was preserved in 94%(50/53) of patients. The overall 5-year survival rate(Kaplan-Meier) was 81.5%. In radiation failure group, 56% of patients were recurred after laser surgery. Conclusion: Laser surgery could be a better treatment modality for early laryngeal cancers and selected advanced cases. Additional radiation therapy should be considered if resection margin is not satisfactory.

• Medical Lasers
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• 제10권2호
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• pp.68-75
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• 2021

Medical lasers have been widely used for various diseases. Despite the notable benefits, lasers could cause several complications such as skin burn, eye injury, airway fire, and so on. These accidents may occur not only with patients, users of the laser, or laser handlers but also to people passing in front of the laser treatment room. Although there is a risk associated with the laser, most of them can be prevented through good training, use of proper protection equipment, and ensuring the safe operation of the laser at all times. Due to the increasing use of lasers and the growing interest in their use, medical institutions should particularly emphasize the safe use of lasers and introduce systems for laser safety.

• Journal of Mechanical Science and Technology
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• 제14권7호
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• pp.744-751
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• 2000

To achieve lower flying height for high areal recording density, the laser zone texturing of the disk needs to be designed to reduce glide height. One problem of the laser bump design is that the regular laser bump pattern often produces glide resonance phenomenon, which leads to failure of the glide height test. However, it was found in this study that glide resonance is an intrinsic problem of the glide head used and resonance phenomenon depends on the type of the head slider, that is, the natural frequency of the slider body. Therefore, higher glide height or glide failure caused by glide resonance does not lead to head/media interface problem in the real drive operating conditions in which the data head is used. Pseudo-random bump pattern greatly reduces the glide resonance. Smaller bump pitch will also help to reduce the glide resonance. However, as bump spacing becomes smaller, glide height will be increased due to increased air pressure developed around the bumps. Lowering bump height is the most effect way to reduce glide avalanche.

• Medical Lasers
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• 제10권2호
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• pp.111-114
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• 2021

A 38-year-old man visited the hospital for a voice change that began two months previously. There were no other accompanying symptoms; the patient had a history of 20 years of smoking. Carbon dioxide (CO₂) laser cordectomy was performed on the left side of the vocal cord, and the biopsy results showed squamous cell carcinoma. Radiation therapy was not performed, and CO₂ laser cordectomy was performed again because of a recurrence of left vocal cord mass three years after a progress observation.

• Medical Lasers
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• 제10권4호
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• pp.238-241
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• 2021

Laryngomalacia is the most common laryngeal malformation that occurs mainly in newborns and children. Symptoms include inspiratory high pitched wheezing, dyspnea, and cyanosis. In most cases, symptoms aggravate until eight months and gradually disappear without any treatment as the patient grows older, but surgical treatment is required in severe cases. The surgical treatment options include epiglottoplasty, supraglottoplasty, aryepiglottoplasty, tracheostomy, and many others performing a resection of excessive mucosa in the larynx. Unlike conventional surgeries, the authors recently treated a case of a two-month-old infant with severe laryngomalacia using a CO₂ laser. After performing CO₂ laser surgery twice, the patient was cured without complications.

• 대한기관식도과학회지
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• 제5권2호
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• pp.153-158
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• 1999

Background and Objectives : The treatment of supraglottic stenosis remains a challenging problem in the field of otolaryngology due to its association with dyspnea, dysphagia, and frequent recurrence. Any satisfactory treatment is not yet known. The author experienced six cases of supraglottic stenosis and report the successful treatment of five cases by repeated endoscopic laryngeal excision with KTP-532 laser under suspension layngoscopy. Materials and Methods : Six adults who were treated for supraglottic stenosis between March 1994 and December 1998 at the Department of Otoloaryngology-Head and Neck Surgery, Korea University Medical Center were studied retrospectively. The patients were placed under general anesthesia followed by endoscopic laryngeal excision with KTP-532 laser under supension laryngoscopy. The scar tissue and granulation tissue were visualized with an operating microscope, and then removed using KTP-532 laser (15watts, continuous mode). Intraoperative local steroid(Triamcinolone ) was injected in all cases after the stenotic portions were removed. Results : Endoscopic excision was performed in five cases ; among the five cases, cricoid cartilage was concomitantly removed in two cases, and epiglottis was removed in one case. Satisfactory swallowing and airway respiration were possible in all five patients who underwent endoscopic widening. Conclusion : The treatment of supraglottic stenosis is different from that of tracheal or glottic stenosis in that supraglottic stenosis is mainly developed in membraneous form. Repeated laser excision and local steroid injection under suspension laryngoscopy is an effective and recommend able method for the treatment of supraglottic stenosis.

• 대한후두음성언어의학회지
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• 제22권1호
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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.

• 대한후두음성언어의학회지
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• 제24권1호
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• pp.13-17
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• 2013

Laser laryngeal microsurgery is currently the primary method of treatment of various laryngeal diseases. The development of laryngeal microsurgery came from the introduction of a small spot $CO_2$ laser micromanipulator and more precise microlaryngeal instruments. $CO_2$ laser laryngeal microsurgery has enabled very precise surgery because it has small focus size and hemostatic effect. There are some limitations to the use of the $CO_2$ Laser such as adjacent tissue damage and vocal fold scarring. These problems can be minimized through understanding the mechanisms by which lasers function and correctly manipulating the parameters under a surgeon's control. We should also recognize the safety of $CO_2$ laser for the surgeon to precisely perform the procedure.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.68-69
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• 2009

Heat Assisted Magnetic Recording (HAMR) is one of the most promising candidates for high density magnetic storages over 1 Tb/$in^2$ areal density. Since the precise light delivery to the head is a key factor to realize HAMR application, it is required to establish the light delivery using micro laser module and micro actuator. For the careful control of micro actuator, a laser module was designed including laser diode, optical fiber, collimating lens, and fabricated V-groove substrate. In addition, the basic aligning method between the laser module and HAMR head was studied by the detection of current change in photo diode due to the amount of reflected light from the head.

• Medical Lasers
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• 제8권2호
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• pp.84-86
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• 2019

Pyriform sinus cyst is a rare disease. This disease can be found by chance or appear as lymph nodes with cancer, infections, shortness of breath, or airway compromise, and can be an unusual cause of dysphonia. This paper presents a case of a pyriform sinus cyst in the pharyngeal wall of the left pyriform sinus, which presented as neck discomfort in a 63-year-old female. The plan was to remove this cyst with a transoral CO₂ laser because a CO₂ laser is a useful tool for removing cysts without bleeding and consuming time. The excision was performed successfully. Transoral laser pyriform sinus cyst excision is a simple, safe, and effective method for the treatment of pyriform sinus cysts. This procedure is likely to be used as a selective treatment when managing this condition.