• Medical Lasers
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• v.10 no.3
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• pp.146-152
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• 2021

Background and Objectives Although lasers have been widely applied in tissue treatment, the light penetration depth in tissues is limited by the tissue turbidity and affected by its absorption and scattering characteristics. This study investigated the effect of using an optical clearing agent (OCA) on tissue to improve the therapeutic effect of 1064 nm wavelength laser light by reducing the heat generated on the skin surface and increasing the penetration depth. Materials and Methods A diode laser (λ = 1064 nm) was applied to a porcine specimen with and without OCA to investigate the penetration depth of the laser light and temperature distribution. A numerical simulation using the finite element method was performed to investigate the temperature distribution of the specimen compared to ex-vivo experiments using a thermocouple and double-integrating sphere to measure the temperature profile and optical properties of the tissue, respectively. Results Simulation results showed a decrease in tissue surface temperature with increased penetration depth when the OCA was applied. Furthermore, both absorption and scattering coefficients decreased with the application of OCA. In ex-vivo experiments, temperatures decreased for the tissue surface and the fat layer with the OCA, but not for the muscle layer. Conclusion The use of an OCA may be helpful for reducing surface heat generation and enhance the light penetration depth in various near-infrared laser treatments.

• Journal of Biomedical Engineering Research
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• v.33 no.3
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• pp.128-134
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• 2012

Currently, high-intensity laser therapy (HILT) is increasingly used in various muscle disorders like muscle tension. Our proposed study includes the development of the real-time monitoring system using a myotonometer for HILT. The developed system consists of a piezoelectric sensor and laser distance sensor for muscle stiffness monitoring during the treatments. The results demonstrated that the level of muscle tension was rapidly decreased after 3 minutes of the high-intensity laser treatment when compared to the control group. The combined HILT and realtime muscle tension monitoring system may help to evaluate the therapeutic procedure and efficient treatments for various muscle pains.

• Journal of the Optical Society of Korea
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• v.19 no.3
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• pp.277-283
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• 2015

In this study, we evaluated the muscle tension in hemiplegia patients using a real-time monitoring system combined with high-intensity laser treatment (HILT) device. Five hemiplegia patients were treated with HILT in the left forearm muscle for 8 minutes, and the muscle was relaxed for 8 minutes following the treatment. Both the gradient of the force-displacement curves and the muscle hardness decreased during the therapy, and the effects were maintained following the treatment. The results show that muscle tension decreased rapidly during laser irradiation, and the efficacy of the treatment depended on the duration of the illness. Consequently, we conclude that this combined HILT and real-time muscle tension monitoring system is useful for evaluating the therapeutic procedure and for treatment of muscle pain.

• Medical Lasers
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• v.9 no.1
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• pp.1-5
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• 2020

Hearing organs have unique characteristics and have a role in processing external sensory signals. Sensory hair cells and nerve fibers in the organ of Corti can be damaged by various causes and they do not regenerate themselves. Medication used for clinical treatment for the inner ear is limited due to the anatomical structure of the inner ear. Photobiomodulation (PBM) is a therapeutic approach that uses various sources of light and the success of PBM therapy is highly reliant on the parameters of the light sources. The positive effects of PBM have been reported in various clinical fields. This paper summarizes the previously reported research on PBM for the treatment of hearing damage in animal models.

• Medical Lasers
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• v.9 no.2
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• pp.142-149
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• 2020

Background and Objectives A picosecond-domain laser treatment using a microlens array (MLA) or a diffractive optical element elicits therapeutic micro-injury zones in the skin. This study examined the patterns of tissue reactions after delivering multiple pulses of 1,064-nm, MLA-type, picosecond neodymium:yttrium-aluminum-garnet laser treatment. Materials and Methods Multiple pulses of picosecond laser treatment were delivered to ex vivo human or brown micropig skin and analyzed histopathologically. A high-speed cinematographic study was performed to visualize the multiple pulses of picosecond laser energy-induced skin reactions in in vivo human skin. Results In the ex vivo human skin, a picosecond laser treatment at a fluence of 0.3 J/cm² over 100 non-stacking passes generated multiple lesions of thermally-initiated laser-induced optical breakdown (TI-LIOB) in the epidermis and dermis. In the ex vivo micropig skin, stacking pulses of 20, 40, 60, 80, and 100 at a fluence of 0.3 J/cm² generated distinct round to oval zones of tissue coagulation in the mid to lower dermis. High-speed cinematography captured various patterns of twinkling, micro-spot reactions on the skin surface over 100 stacked pulses of a picosecond laser treatment. Conclusion Multiple pulses of 1,064-nm, MLA-type, picosecond laser treatment elicit marked TI-LIOB reactions in the epidermis and areas of round to oval thermal coagulation in the mid to deep dermis.

• The Journal of the Society of Stroke on Korean Medicine
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• v.6 no.1
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• pp.9-16
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• 2005

Objective : The heart rate variability is very useful indicator to study the function of the autonomic nervous system(ANS), and the physiologic signals can be observed based on the changes of the ANS of the heart. In order to assay the effects of the laser exposing to healthy subjects, the double blind test has been performed. Methods : This study included 62 healthy adults who have not any ANS disease and had normal sinus rhythm in electrocardiogram. The control group consisted of 31 subjects, laser group consisted of 31 subject. HRV was measured for 5 minutes before laser irradiation, sham and real laser irradiated for 30 minutes and than HRV remeasured for 5 minutes. Statistical significance was evaluated by independent T-test. Results : Mean HRV, Ln(VLF), Ln(HF), Ln(TP) of both groups at post-laser period decreased compared with that of the pre-laser period. Ln(LF) of both groups at post-laser period increased compared with that of the pre-laser period. LF/HF, SDNN of real laser group decreased and sham group decreased. Conclusions : There is no difference between two groups. The reason is presumed that all the studied subjects are healthy adults, and also the short and single transcutaneous laser irradiation would not influence upon changes of the ANS. The further study must be followed.

• Journal of the Optical Society of Korea
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• v.15 no.4
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• pp.373-379
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• 2011

Current therapeutic methods for suppressing muscle spasticity are intensive functional training, surgery, or pharmacological interventions. However, these methods have not been fully supported by confirmed efficacy due to the aggravation of the muscle spasticity in some patients. In this study, a combined system was developed to treat with a low-level laser and to monitor the region of the treatment using an optical spectroscopic probe that measures oxygen saturation and deoxygenation during low-level laser therapy (LLLT). The evaluation of the wavelength dependence for LLLT was performed using a Monte Carlo simulation and the results showed that the greatest amount of heat generation was seen in the deep tissue at ${\lambda}$ = 830 nm. In the oxy- and deoxygenation measurements during and after the treatment, oxygen-Hb concentration was significantly increased in the laser-irradiated group when compared to the control group. These findings suggest that LLLT using ${\lambda}$ = 830 nm may be of benefit in accelerating recovery of muscle spasticity. The combined system that we have developed can monitor the physiological condition of muscle spasticity during the laser treatment in real time and may also be applied to various myotonia conditions such as muscle fatigue, back-pain treatment/monitoring, and ulcer due to paralysis.

• Medical Lasers
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• v.10 no.3
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• pp.176-180
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• 2021

Several methods have been used to treat androgenetic hair loss, ranging from hair transplants to finasteride and minoxidil. Sometimes platelet-rich plasma injection therapy may be used to increase the satisfaction of patients who come to the hospital. However, some patients are sensitive to pain and are subjected to the inconvenience of requiring treatment after each blood sampling. The author had reported the effects of using a hair growth-promoting solution and Jetpeel^TM in parallel with a painless hair loss treatment method. However, the author was interested in more effective methods for patients with M-shaped or vertex hair loss who do not want to take medications or undergo hair transplant. In addition to the existing light-emitting diode therapy and electromagnetic field treatment, the author has made considered attempts to use various laser wavelength bands. However, the equipment for these methods can be expensive and are not suitable for patients who emphasize on cost-effectiveness. Therefore, the author used an existing reported method and a device based on the fractional erbium:YAG laser to provide the hair growth-promoting solution in parallel. The author chose a fractional 2940 nm-based laser device as a medium that could efficiently increase the growth phase, reduce the catagen phase, and facilitate intradermal product and drug delivery. As a result, there was a therapeutic benefit without any significant side effects such as redness and itching. Among the patients, the author reported the effects of the treatment on one patient with frontal M-shaped, mid, and vertex hair loss.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.26 no.1
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• pp.63-74
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• 2013

Objective : Low level laser therapy(LLLT) is conjugated many different diseases such as skin disease, nervous system disease, cardiovascular disease, etc. This study was tried to survey the conjugation of LLLT in field of ophthalmology, otolaryngology and dermatology of Korean Medicine. Methods : In this study, LLLT deal with the field of ophthalmology, otolaryngology and dermatology was searched at Pubmed and NDSL. We searched Pubmed and NDSL with the title "Laser Therapy and Low-Level" for the last 10 years and analyzed disease, laser type, sample size, effect, journal and year. Results : Using Pubmed and NDSL, 8 treatises were researched. About 8 treatises, 7 treatises were papers in field of dermatology, 1 treatise was ophthalmology. And about 8 treatises, 6 treatises were foreign papers and 2 treatises were domestic papers on clinical application of laser status. Mainly used type of laser was a He-Ne laser and Diode laser. The diseases were ocular hypertension, acne, ulcers in patients with leprosy sequelae, freckles, segmental-type vitiligo lesions, diabetes-linked skin lesion, facial skin melanin and elasticity, atopic dermatitis symptom. As a result, we found that treat group had more improvement than control group in 7 of the 8 treatises, that treat group had no difference control group on effect significantly only 1 treatise. Conclusions: As therapeutic tool, LLLT's application range is very wide in the field of ophthalmology, otorhinolaryngology, and dermatology. Keep up with the increasing interest of domestic and foreign about laser therapy, clinical tries on the use of laser will be studied steadily. It is necessary to have sustained attention and research on the point of view of the Korean Medicine.

• Journal of the Optical Society of Korea
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• v.17 no.4
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• pp.289-295
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• 2013

Although low-level laser therapy (LLLT) has been a valuable therapeutic technology in the clinic, its efficacy may be reduced in deep tissue layers due to strong light scattering which limits the photon density. In order to enhance the photon density in deep tissue layers, this study developed an optical tissue clearing (OTC) laser probe (OTCLP) system which can utilize four different OTC methods: 1) tissue temperature control from 40 to $10^{\circ}C$; 2) laser pulse frequency from 5 to 30 Hz; 3) glycerol injection at a local region; and 4) a combination of the aforementioned three methods. The efficacy of the OTC methods was evaluated and compared by investigating laser beam profiles in ex-vivo porcine skin samples. Results demonstrated that total (peak) intensity at full width at half maximum of laser beam profile when compared to control data was increased: 1) 1.21(1.39)-fold at $10^{\circ}C$; 2) 1.22 (1.49)-fold at a laser pulse frequency of 5 Hz; 3) 1.64 (2.41)-fold with 95% glycerol injection; 4) 1.86 (3.4)-fold with the combination method. In conclusion, the OTCLP system successfully improved the laser photon density in deep tissue layers and may be utilized as a useful tool in LLLT by increasing laser photon density.