• Tuberculosis and Respiratory Diseases
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• v.52 no.1
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• pp.54-61
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• 2002

Background: Tracheal stenosis is an urgent but uncommon disease. Therefore, primary care clinicians have limited clinical experience. Animal models of a tracheal stenosis can be used conveniently for the learning, teaching, and developing new diagnostic and therapeutic modalities for tracheal stenosis. Recently, a canine model of a tracheal stenosis was developed using a Nd-YAG laser. To describe the methods and results of developed animal model, we performed this study. Methods : Six Mongrel dogs were generally anesthetized and the anterior 180 degree of tracheal cartilage of the animal was photo-coagulated using a Nd-YAG laser. The animals were bronchoscopically evaluated every week for 4 weeks and a pathologic evaluation was also made. Results : Two weeks after the laser coagulation, the trachea began to stenose and the stenosis progressed through 4 weeks. All animals suffered from shortness of breath, wheezing, and weight loss in the 3 weeks after the laser treatment, and two died of respiratory failure just before the fourth week. The gross pathologic findings showed the loss of cartilage and a dense fibrosis, which resulted in a fibrous stricture of the trachea. Microscopy also showed that the fibrous granulation tissue replaced destroyed cartilage. Conclusion : The canine model can assist in the understanding and development of new diagnostic and therapeutic modalities for tracheal stenosis.

• Archives of Plastic Surgery
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• v.43 no.6
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• pp.570-574
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• 2016

Background Fractional $CO_2$ laser is an effective treatment for scars, but most patients complain about sharp burning pain, even after the application of lidocaine ointment. This study analyzed the impact of a vibrating device to nonpharmacologically reduce the acute pain of laser treatment, in accordance with the gate control theory of pain management. Methods This is a prospective study performed from May 2013 through March 2014. Fifty-three patients (mean age, 26.7 years; range, 16-44 years) who had donated livers for liver transplantation were treated with a fractional $CO_2$ laser (10,600 nm; model $eCO_2$, Lutronic Corp) for their abdomen scars. Laser treatment was applied 4 months after surgery. A commercially available, locally applied vibrating device (model UM-30M, Unix Electronics Co. Ltd.) was used, in an on-and-off pattern, together with the $CO_2$ laser. A visual analogue scale (VAS; 0, no pain; 10, most severe pain) of pain sensation was assessed and statistically analyzed using a paired t-test. Results The average VAS score for pain with the vibrating device was 4.60 and the average VAS score without the vibrating device was 6.11. The average difference between scores was 1.51 (P=0.001). Conclusions A locally applied vibrating device was demonstrated to be effective in reducing pain when treating with a fractional $CO_2$ laser. Vibration treatment could be helpful when treating scars with fractional $CO_2$ laser in pain-sensitive patients, particularly children.

• Journal of Biomedical Engineering Research
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• v.42 no.3
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• pp.116-124
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• 2021

It is important to differentiate between the target tissue (or organ) and the rest of the tissue before incision during surgery. And when it is necessary to preserve the differentiated tissues, the blood vessels connected to the tissue must be preserved together. Various non-invasive medical imaging methods have been developed for this purpose. We aimed to develop a medical imaging system that can simultaneously apply fluorescence imaging using indocyanine green (ICG) and laser speckle contrast imaging (LSCI) using laser speckle patterns. We designed to collect images directed to the two cameras on a co-axial optical path and to compensate equal optical path length for two optical designs. The light source used for fluorescence and LSCI the same 785 nm wavelength. This system outputs real-time images and is designed to intuitively distinguish target tissues or blood vessels. This system outputs LSCI images up to 37 fps through parallel processing. Fluorescence for ICG and blood flow in animal models were observed throughout the experiment.

• Journal of the Korean Physical Therapy Association
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• v.5 no.1
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• pp.29-34
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• 1983

• Journal of Biomedical Engineering Research
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• v.36 no.5
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• pp.191-197
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• 2015

Laser acupuncture is defined as the stimulation of traditional acupuncture points with low-intensity, nonthermal laser irradiation. Possible advantages in using laser acupuncture are the noninvasive, painless and low risks of infection treatment. The purpose of this study is to assess the effect of laser acupuncture on the quality and waveform of arterial pulses. Ten acupuncture points were stimulated repeatedly three times in 30 individuals by laser with emission in the near infrared spectral region (808 nm) using an out power and power density of 45 mW and $143W/cm^2$. The analysis of pulse quality and waveform was performed based on the measurement of arterial pressure of the left and right wrist, using a 3-dimensional blood pressure pulse analyzer. Excess-like pulse quality of subjects before laser acupuncture changed significantly to balanced pulse quality after 10, 20, and 30 minutes of laser acupuncture; coefficient of deficient or excess, $C_{DE}$, decreased significantly from 0.68 before acupuncture to 0.61, 0.55, and 0.55 after 10, 20, 30 minutes of laser acupuncture ($$p{\leq_-}0.006$$), respectively. Other pulse qualities, floating or sinking, slow or rapid, choppy or slippery did not change significantly by laser acupuncture (p > 0.05). Pulse waveform analysis showed that amplitude of main peak (systolic function or aortic compliance, $h_1$) of left and right artery pulse waves decreased significantly after 10, 20, and 30 minutes of laser acupuncture (p < 0.05). Other parameters, duration of one cardiac cycle (T), duration of rapid systolic ejection ($T_1$), duration of the systolic phase ($T_4$), and duration of the diastolic phase ($T_5$) of left and right artery pulses did not change significantly after laser acupuncture (p > 0.05).

• The korean journal of orthodontics
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• v.48 no.2
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• pp.90-97
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• 2018

Objective: The aim of this study was to assess the analgesic effect of a single application of low-level laser therapy (LLLT) on spontaneous pain and pain on chewing after placement of initial archwires. Methods: Forty-two patients (26 women, 16 men) were randomly recruited for this split-mouth randomized clinical trial. Each patient received super-elastic nickel-titanium (NiTi) initial archwires (0.012, 0.014, 0.016, and 0.018-inch [in]) in the maxilla for leveling and alignment for an interval of 4 weeks between archwires. One side of the mouth was randomly designated as experimental, while the other side served as placebo. After insertion of each archwire, the experimental side was irradiated with a diode laser for 3 seconds each on 5 points facially and palatally per tooth, from the central incisor to first molar. On the placebo side, the laser device was held the same way but without laser application. A numerical rating scale was used to assess the intensity of spontaneous and masticatory pain for the following 7 days. The Mann-Whitney U test was used to compare pain scores between sides. Results: Patients in the LLLT group exhibited significantly lower mean scores for spontaneous pain after insertion of the initial two archwires (0.012-in and 0.014-in NiTi; p < 0.05), while there was no significant difference for 0.016-in and 0.018-in wires between the LLLT and placebo groups. LLLT significantly reduced chewing pain scores (p < 0.05) for all archwires. Conclusions: A single dose of LLLT considerably lessened postoperative pain accompanying the placement of super-elastic NiTi wires for initial alignment and leveling.

• Clinical Pain
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• v.19 no.1
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• pp.1-7
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• 2020

Objective: A prospective, assessor-blinded, randomized controlled trial was conducted in patients with chronic low back pain to evaluate the efficacy of portable low power laser therapy (LPLT) and the effect when combined with exercise therapy on pain and functions. Method: 60 patients were recruited and 56 patients, excluding 4 dropouts, were randomly allocated to the LPLT group (Group 1: 19 patients), placebo laser therapy with exercise group (Group 2: 18 patients), and LPLT with exercise group (Group 3: 19 patients). Laser therapy and exercise was performed five times a week for 4 weeks. Visual analogue scale (VAS), Schober test, lumbar range of motion (ROM) measures (flexion, extension and lateral flexion), Oswestry Disability index (ODI) were measured at baseline, at 4 weeks after intervention, and at 6 weeks after 2 weeks of no intervention. Results: Statistically significant improvements were noted in all group by time interaction with respect to all outcome parameters (p<0.05). All parameters in each group improved not only in the period of treatment (4 weeks), but also in the final evaluation (6 weeks) 2 weeks after the end of treatment. Post-hoc analysis showed statistically significant difference between the LPLT with exercise group and the other groups in all outcome parameters except for the ODI at 4 weeks and at 6 weeks. Conclusion: Portable LPLT is effective treatment in reducing pain and improving lumbar ROM and with exercise is more effective than laser or exercise monotherapy for the chronic low back pain patients.

• Medical Lasers
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• v.10 no.1
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• pp.52-54
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• 2021

There is growing interest in minimizing postoperative scarring after a thyroidectomy. Among the many treatment types, laser therapy, especially picosecond-domain laser therapy, is accepted as a standard method. In the present case, a patient with a pigmented, contracted scar was treated using the combination of a picosecond laser and ablative fractional (AF) CO₂ laser. After 15 sessions of 1,064-nm picosecond with micro lens array (MLA) and AF CO₂ laser application, the patient showed significant improvement in their pigmented lesions and scar contracture with no noticeable side effects for 16 months. These results suggest that a combination of picosecond laser with MLA and AF CO₂ laser can treat pigmented, contracted scars safely and effectively.

• Journal of the Optical Society of Korea
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• v.13 no.3
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• pp.321-329
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• 2009

Following their applications in cardiology, ophthalmology and dentistry among others, the advent of lasers in dermatology and urology had become the success story of the past decade. Laser-assisted treatments in dermatology and urology are mainly based on the laser-induced tissue injury/coagulation and/or ablation, depending upon the desirable clinical endpoint. In this review, we discussed the underlying mechanisms of the laser induced tissue ablation. In any medical laser application, the controlled thermal injury and coagulation, and the extent of ablation, if required, are critical. The laser thermal mechanism of injury is intricately related to the selective absorption of light and its exposure duration, similarly to the laser induced ablation. The laser ablation mechanisms were categorized into four different categories (the photo-thermally induced ablation, the photo-mechanically induced ablation, the plasma induced ablation and the photoablation) and their fundamentals are herein described. The brief history of laser treatment modality in dermatology and urology are summarized.

• Journal of Biomedical Engineering Research
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• v.31 no.1
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• pp.81-86
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• 2010

Laser irradiation is known to affect various tissues such as skin, bone, nerve, and skeletal muscle. Laser irradiation promotes ATP synthesis, facilitates wound healing, and stimulates cell proliferation and angiogenesis. In skeletal muscle, laser irradiation is related to the proliferation of skeletal muscle satellite cells. Normal skeletal muscle contains remodeling capacity from myogenic cells that are derived from mononuclear satellite cells. Their processes are activated by the expression of genes related with myogenesis such as muscle-specific transcription factors (MyoD and Myf5) and VEGF (vascular endothelial growth factor). In this study, we hypothesized that laser irradiation would enhance and regulate muscle cell proliferation and regeneration through modulation of the gene expressions related with the differentiation of skeletal muscle satellite cells. $C_2C_{12}$ myoblastic cells were exposed to continuous/non-continuous laser irradiation (660nm/808nm) for 10 minutes daily for either 1 day or 5 days. After laser irradiation, cell proliferation and gene expression (MyoD, Myf5, VEGF) were quantified. Continuous 660nm laser irradiation significantly increased cell proliferation and gene expression compared to control, continuous 808nm laser irradiation, and non-continuous 660nm laser irradiation groups. These results indicate that continuous 660nm laser irradiation can be applied to the treatment and regeneration of skeletal muscle tissue.