• Title/Summary/Keyword: medical laser

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Effects of Various Laser Wavelengths and Power Densities on the Ocular Damage in Pigmented Rats

  • Chung, Phil-Sang;Shin, Jang-In;Chang, Moo-Hwan;Chang, So-Young;Kang, Jung-Wook;Hwang, Hee-Jun;Ahn, Jin-Chul
    • Biomedical Science Letters
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    • v.14 no.3
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    • pp.173-178
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    • 2008
  • With the widespread use of laser in medical and industrial settings, the incidence of laser injury to the ocular continues to grow among workers involved in handling lasers. The aim of this study is to compare ocular damages after irradiation with various laser wavelengths and power density. Ocular of pigmented rats was irradiated with $CO_2$ laser, 1064 nm Nd:YAG laser, and 532 nm diode laser. We observed damage of cornea, lens, and retina using slit lamp microscope and funduscopy. H&E staining of histopathology were applied to study the specimens. The higher exposure ($200mW/cm^2$, 10 sec) with $CO_2$ laser resulted in severe damage at the cornea. For the 1064 nm Nd:YAG laser, the higher exposure than $10mW/cm^2$ (10 sec) resulted in damage at the cornea and lens. Further, with the 532 nm diode laser, retinal lesions were induced when $10mW/cm^2$ (0.25 sec) was delivered to the eye. Theses results suggest that the ocular damages are different from various laser wavelength and power density.

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Safe Use of Medical Lasers

  • Woo, Seung Hoon;Chung, Phil-Sang;Lee, Sang Joon
    • Medical Lasers
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    • v.10 no.2
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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.

Femtosecond laser induced shock generation and its application (펨토초 레이저 유발 shock 형성 및 그 응용)

  • Jeoung, Sae Chae;Lee, Heung Soon;Sidhu, M.S.;Moon, Heh-Young
    • Laser Solutions
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    • v.17 no.4
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    • pp.1-6
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    • 2014
  • Femtosecond laser induced shock generation in water and vitreous humor of enucleated porcine eyeball was investigated. When focusing the femtosecond laser into the liquid mediums, the acoustic waves with a frequency of about 15.6kHz could be observed by using wide-band microphone. The amplitude of the acoustic signals from water has attained a maximum under a laser power of about 5mW. Further increment of the power results in a decrement of the acoustic signals due to nonlinear optical process including filamentation of laser beam. We have further investigated the effect of femtosecond laser induced acoustic waves by applying the laser pulse into enucleated porcine eyeball. The comparative studies on both healthy and diseased eyeballs led us propose that the femtosecond laser pulses could be utilized as a novel tools for treatment of partially detached retina layers from their choroid structures.

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An Analysis of the Correlation between He-Ne Laser Therapy in Literature and Clinical Application (He-Ne 레이저에 대한 문헌과 이를 근거로 한 임상 활용 예의 비교 고찰)

  • Youn, In-Hwan;Kim, Nam-Kwen
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.19 no.2
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    • pp.192-201
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    • 2006
  • Objectives : Recently, He-Ne laser has been used for clinical purpose. We study the medical basis of He-Ne laser therapy and We make a proposal concerning the clinical application of using He-Ne laser in Medicine. Methods : We have selected data related to He-Ne laser therapy and study how to use He-Ne laser in clinic. Results : In biology, He-Ne laser therapy has been effects of an improve in skin regeneration an improve in peripheral and central nerve regeneration an improve in muscle regeneration, an anti-inflammation an alleviation of pain and a bone repair. In oriental medicine, He-Ne laser has been used to laser acupuncture and laser oriental physical treatment. In clinic, He-Ne laser have been used to care several parts like as facial palsy, facial spasm, trigeminal neuropathy, rhinitis and tinnitus. Recently, there is argument that He-Ne laser therapy is suitable to medical insurance. Conclusions : Laser therapy in oriental medicine is widespread and We can apply He-Ne laser to facial palsy, facial spasm, trigeminal neuropathy, rhinitis, tinnitus by using laser acupuncture or laser oriental physical treatment. Till now the whole mechanisms are not fully understood, so we hope to study these mechanisms actively and make suitable to medical insurance device in the near future.

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Histological Change and Collagen Formation on Laser Wounded Rat using 808 nm Diode Laser and $CO_2$ Laser

  • Chung, Phil-Sang;Shin, Jang-In;Chang, So-Young;Ahn, Jin-Chul
    • Biomedical Science Letters
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    • v.15 no.1
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    • pp.81-86
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    • 2009
  • Lasers are necessity in our life related to the fields of medicine and cosmetic surgery. With 808 nm diode laser and $CO_2$ laser, we made some wounds on a dorsum of rat by laser irradiation. All of irradiations shows thermal effects on the whole region of skin tissues. They make wound damage depending on laser power and irradiation time. Because a collagen is plays an important role in tissue repair, we studied collagen accumulation in wound tissue. For wound healing, collagen accumulation was found in the near region of damage in epidermis and dermis layer of the rat skin. In case of the quantitative analysis of collagen in wound tissue, the amount of collagen in wound tissue by $CO_2$ laser irradiation is higher than that of 808 nm diode laser irradiation. And re-epithelialization was significantly faster in wound by $CO_2$ laser irradiation compared with that of 808 nm diode laser irradiation.

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The Effect of Low-power Laser on the Murine Hair Growth (저출력 레이저가 마우스 모발성장에 미치는 영향)

  • Chung, Phil Sang;Kim, Jin Wang;Lee, Jeong Ok;Ree, Chung Ku;Oh, Chung Hoon;Kim, You Chan;Chung, Sang Woon
    • Archives of Plastic Surgery
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    • v.32 no.2
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    • pp.149-154
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    • 2005
  • Low-power laser(LPL) delivers a small amount of energy without elevation of tissue temperature. LPL has been reported to have biostimulation effects including anti-inflammatory, analgesic, regenerative, immunocorrective, and vasodilative effects. However, the effect of LPL on hair growth has rarely been studied. We investigated the effect of LPL on hair growth in the mouse. After depilation of back skin of mice, we classified the mice into 4 groups: control, laser irradiated group, $MoandMore^{(R)}$ applied group, and Spella $707^{(R)}$ applied group. Laser irradiation or application of these drugs were performed on the back skin of the mice for 30 days. The results are summarized as follows. Hair growth of control was first observed at 13 days after depilation, and complete hair regrowth was observed at 25 days. Hair growth of both laser irradiation group and $MoandMore^{(R)}$ applied group was first observed at 9 days after depilation, and complete hair regrowth was observed at 20 days. Hair growth of Spella $707^{(R)}$ applied group was firstly observed at the 9 days after depilation, and complete hair regrowth was observed at the 15 days. Hair growth started at the irradiation site in the laser irradiation group, but it started at the random sites in other groups. In conclusion LPL irradiation have a stimulating effect on the hair growth in the mouse.

Four cases of vitiligo patients treated by Oriental medical treatment who have experienced Excimer Laser treatment (엑시머레이저 치료를 경험했던 백반증 환자가 한방복합치료와 엑시머레이저 병행치료로 호전된 치험 4례)

  • Lee, Jin-Hyuk;Kim, Se-Yoon
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.27 no.3
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    • pp.205-212
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    • 2014
  • Purpose: This study aims to prove effects of an oriental medical complex therapy on vitiligo patients who have experienced the Eximer laser therapy. Method: The study conducted its investigation targeting these four patients who have not been observed with any satisfactory reaction to the Eximer laser therapy. The study analyzed the findings through the comparison on the pictures before and after the therapy. Result: After comparing the pictures, the study confirmed positive changes in the conditions of the patients. The oriental medical complex therapy turned out to be effective enough to treat the patients who have gone through the Eximer laser therapy before. Conclusion: Such result leads the study to a conclusion that the oriental medical complex therapy can be an effective way to treat these patients who do not have a satisfactory reaction to the Eximer laser therapy. In addition, the author of the study suggests that more clinical trials should be conducted.

Efficacy and Safety of Laser Surgery and Transurethral Resection of the Prostate for Treating Benign Prostate Hyperplasia: a Network Meta-analysis

  • Wang, Li;Yu, Qiu-Yan;Liu, Yan;Zhu, Zhen-Li;Huang, Yuan-Wei;Li, Ke
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.9
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    • pp.4281-4288
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    • 2016
  • Background: Traditional meta-analyses or systematic reviews of randomized controlled trials (RCTs) have been used to compare laser surgeries and transurethral resection of the prostate (TURP) for benign prostate hyperplasia (BHP), but they cannot provide a hierarchy regarding efficacy and safety of treatment. Objective: We therefore performed a network meta-analysis (NMA) to compare and create hierarchies for efficacy and safety of TUPR and laser surgeries for BPH. Materials and Methods: We searched for reports of RCTs published up to April 25, 2015. After methodological quality assessment and data extraction, we performed an NMA to compare TURP and laser surgeries for BPH. Results: We ranked the treatments of TURP and laser surgeries for BPH. For IPSS at 6 months, holmium laser resection of the prostate (HoLRP) ranked the first-best and at 12 months, holmium laser enucleation of the prostate (HoLEP). For Qmax at 6 and 12 months, HoLEP ranked the first-best; for operative time it was TURP; for cathedral removal time, diode laser enucleation of the prostate (DiLEP) ranked the first-best. Conclusions: Although TURP is considered the gold standard for treating BPH, it is not better in terms of efficacy and safety compared with the laser surgery. Our NMA created hierarchies for the 9 types of surgery in terms of efficacy and safety, which should help clinicians choose the best approach for the individual patient.