• 공업화학
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• 제7권6호
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• pp.1027-1033
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• 1996

쌍극자물질에 전자파를 조사하면 그 파동의 변화에 따라 분자가 진동하며, 이웃 분자와 마찰을 일으켜 물질 내부로부터 가열되는 독특한 현상을 보인다. 따라서 고체인 전자파흡수제에 흡착시킨 쌍극자 기체를 microwave energy로 쉽게 파괴할 수 있다. 연소기기 배출가스에서 산성가스 제거공정 개발을 위하여 이 방법에 의한 산성가스 분해실험을 실시하였다. Calcined char는 전자파흡수제 및 가스 흡착제로서의 역할을 하는데, NO와 $SO_2$를 함유한 표준가스를 char bed내로 통과시키면서 microwave를 조사하였다. Microwave가 조사되고 있는 20 gram의 char bed를 통과하는 동안 95% 이상의 NO와 70% 이상의 $SO_2$가 환경적으로 무해한 단체원소로 분해되었으며, 분해된 원소 중 산소기는 char의 기공내에서 탄소와 반응하여 $CO_2$를 형성하며 char의 기공도 및 표면적 증대효과를 가져왔다. 일반적인 상업적 연소공정에서 처럼 이보다 낮은 농도에서는 거의 완전한 분해가 가능하리라 보여지며, 대기오염 방지에 좋은 방법이 되리라 믿어진다.

• 대한정형도수물리치료학회지
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• 제15권2호
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• pp.93-97
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• 2009

Anatomy: Facet joint syndrome most often affects the lower back and neck and refers to pain that occurs in the facet joints, which are the connections between the vertebrae in the spine that enable the spine to bend and twist. Many physicians have believed that the usual lesion of facet syndrome was an anatomical impairments of facet joint itself.. Facet joint injection using local anesthetics is a reliable method for the diagnosis and treatment for facet syndrome. Etiology: One of many possible causes is imbalances that can occur in stress levels, hormone levels, and nutritional levels. These imbalances can adversely affect posture, which can lead to neck and back pain. The common disorder called facet syndrome exhibits lower back pain, with or without, radiating pain to buttock and thigh due to facet joint arthropathy. Pain in the facet joint is supposedly the secondary effect of narrowing of joint space by sustained muscle contracture around joints. Syndrome: Facet joint syndrome tends to produce pain or tenderness in the lower back that increases with twisting or arching the body, as well as pain that moves to the buttocks or the back of the thighs. Other symptoms include stiffness or difficulty standing up straight or getting out of a chair. Pain can be felt in other areas such as the shoulders or mid-back area. Treatment: Non-drug treatments include hot packs, ultrasound, electrical stimulation, and therapeutic exercises. Stimulating blood flow using massage or a hot tub may also help. Alternative treatments include yoga and relaxation therapy. If your pain persists after trying these treatments, a surgical procedure called radiofrequency rhizotomy, which destroys the sensory nerves of the joint, may bring relief. Facet joint injection has been helpful in diagnosis and therapy for this facet syndrome. Radiofrequency thermocoagulation of medial branches is known to be an effective method of relieving pain caused by facet joint problems. We conclude that spasmolytic treatment of muscles connecting the two vertebral articular space would be better for treatment and diagnosis of facet syndrome rather than facet block with local anesthetic and steroid only.

• 전기학회논문지
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• 제60권7호
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• pp.1417-1426
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• 2011

Radiofrequency ablation through cardiac catheterization is one of minimally invasive intervention procedures used in drug resistant arrhythmia treatment. To facilitate more accurate and precise catheter navigation, systems for robotic cardiac catheter navigation have been developed and commercialized. The authors have been developing a novel robotic catheter navigation system. The system is a network-based master-slave configuration 3-DOF (Degree-Of-Freedom) robotic manipulator for operation with conventional cardiac ablation catheter. The catheter manipulation motion is composed of the translation (forward/backward) and the roll movements of the catheter and knob rotation for the catheter tip articulation. The master manipulator comprises an operator handle compartment for the knob and the roll movement input, and a base platform for the translation movement input. The slave manipulator implements a robotic catheter platform in which conventional cardiac catheter is mounted and the 3-DOF motions of the catheter are controlled. The system software that runs on a realtime OS based PC, implements the master-slave motion synchronization control in the robot system. The master-slave motion synchronization performance tested with step, sinusoidal and arbitrarily varying motion commands showed satisfactory results with acceptable level of steady state error. The developed system will be further improved through evaluation of safety and performance in in vitro and in vivo tests.

• The Korean Journal of Physiology and Pharmacology
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• 제22권3호
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• pp.277-289
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• 2018

The exponential increase in the use of mobile communication has triggered public concerns about the potential adverse effects of radiofrequency electromagnetic fields (RF-EMF) emitted by mobile phones on the central nervous system (CNS). In this study, we explored the relationship between calcium channels and apoptosis or autophagy in the hippocampus of C57BL/6 mice after RF-EMF exposure with a specific absorption rate (SAR) of 4.0 W/kg for 4 weeks. Firstly, the expression level of voltage-gated calcium channels (VGCCs), a key regulator of the entry of calcium ions into the cell, was confirmed by immunoblots. We investigated and confirmed that pan-calcium channel expression in hippocampal neurons were significantly decreased after exposure to RF-EMF. With the observed accumulation of autolysosomes in hippocampal neurons via TEM, the expressions of autophagy-related genes and proteins (e.g., LC3B-II) had significantly increased. However, down-regulation of the apoptotic pathway may contribute to the decrease in calcium channel expression, and thus lower levels of calcium in hippocampal neurons. These results suggested that exposure of RF-EMF could alter intracellular calcium homeostasis by decreasing calcium channel expression in the hippocampus; presumably by activating the autophagy pathway, while inhibiting apoptotic regulation as an adaptation process for 835 MHz RF-EMF exposure.

• Journal of Chest Surgery
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• 제44권1호
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• pp.18-24
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• 2011

Background: We evaluated the efficacy of Cox-maze IV procedure using bipolar irrigated radiofrequency ablation and cryothermy in chronic atrial fibrillation associated with valvular heart disease. Material and Methods: From November 2005 to June 2009, ninety four patients have undergone valvular heart surgery with Cox-maze IV procedure. Preoperative duration of atrial fibrillation was $7.6{\pm}6.5$ years and follow-up duration was $22.7{\pm}12.3$ months. Results: There were two (2.1%) postoperative deaths not related to maze procedure. Two cerebrovascular accidents, five low cardiac output syndromes and two permanent pacemaker implantations have occurred after surgery. Preoperative ejection fraction on echocardiography was $55.3{\pm}8.1%$ and ejection fraction of postoperative six month was $54.7{\pm}6.5%$. Left atrial size of preoperative and postoperative were $61.5{\pm}11.6\;mm$ and $53.1{\pm}8.4\;mm$ at each. Freedom from atrial fibrillation rate at postoperative six-month was 80.7% and the cases of recurrence of atrial fibrillation after six months were three (3.3%). Risk factors for failure or recurrence of maze procedure were old age (p=.010) and preoperative moderate or severe tricuspid regurgitation (p=.033). Conclusion: The Cox-maze IV procedure using RFBP2 and cryothermy is quite safe and freedom from atrial fibrillation at postoperative 6 month was 82.5%. Risk factors for failure or recurrence of atrial fibrillation after Cox-maze IV were old age and preoperative over moderate tricuspid regurgitation.

• Physical Therapy Rehabilitation Science
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• 제11권4호
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• pp.493-501
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• 2022

Objective: The purpose of this study is to present basic data for appropriate therapeutic intervention by confirming changes in the autonomic nervous system and pain by applying high-frequency deep diathermy to the lower abdomen in patients with primary dysmenorrhea. Design: A randomized controlled clinical trial. Methods: Thirty-eight women aged 18-50 years who complained of regular menstrual cycles (24-32 days) and primary dysmenorrhea symptoms were randomly assigned to a high-frequency therapy group (5, 7, or 9 mins) and a superficial heat therapy group (20 min). High frequency treatment group: The subject was in a supine position, and radio frequency was applied to the lower abdomen below the umbilicus. The radio frequency therapy device used in this study uses a 300 kHz capacitive electrode and a 500 kHz resistive electric transfer to deliver deep heat. Superficial heat treatment Group: Subjects applied a hot pack to the lower abdomen for 20 minutes while lying on their back. Evaluations were made of Heart rate variability and Visual Analogue Scale. Results: In subjects with menstrual pain, there was a significant difference in pain between the high-frequency therapy group and the superficial heat therapy group (p=0.026). However, there was no significant difference between the autonomic nervous system and the stress resistance (p>0.05). Conclusions: As a result of this study, high-frequencytreatment using radiofrequency was effective in relieving pain because it can penetrate deeper tissues than conventional hot packs using superficial heat. In particular, it was found that the optimum effect was obtained when high frequency was applied forfive-seven minutes.

• Korean Journal of Radiology
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• 제21권12호
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• pp.1383-1392
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• 2020

Objective: This study aimed to evaluate the efficacy and safety of ultrasound (US)-guided minimally invasive treatment in patients with parathyroid lesions. Materials and Methods: This study included 27 patients who had undergone US-guided radiofrequency ablation (RFA) or ethanol ablation (EA) for parathyroid lesions between January 2010 and 2018. RFA was performed in 19 patients with primary hyperparathyroidism (PHPT, n = 11) or secondary hyperparathyroidism (SHPT, n = 8), and EA was performed in eight patients with symptomatic nonfunctioning parathyroid cysts (SNPCs). Nodule size, volume, serum parathyroid hormone (PTH) and calcium levels were recorded before and after treatment. Complications were evaluated during and after treatment. Results: In patients with PHPT, significant reductions in size and volume were noted after RFA at 6- and 12-month follow-up (all, p < 0.05). Seven nodules nearly completely disappeared (residual volume < 0.1 mL); serum PTH and calcium levels were reduced to normal ranges (7/11, 63.6%). Four patients experienced partial reductions of serum PTH and calcium levels (4/11, 36.4%). In patients with SHPT, three experienced therapeutic response of serum PTH (3/8, 37.5%), while five showed persistent hyperparathyroidism (5/8, 62.5%) within 6 months after RFA. In patients with SNPCs, EA resulted in significant reductions in cyst size and volume (all, p < 0.05) at the last follow-up. A total of four complications (two transient hypocalcemia [RFA], one permanent [RFA], and one transient [EA] hoarseness) were observed. Conclusion: Minimally invasive treatments, such as RFA and EA, may serve as therapeutic alternatives for patients with PHPT or SNPCs; they may have limited usefulness in patients with SHPT.

• 대한영상의학회지
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• 제81권3호
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• pp.530-548
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• 2020

갑상선 영상의학 진료란 갑상선 질환 환자를 영상의학적 방법을 활용하여 질병 진단과 중재적 치료를 하는 의료 행위로 정의될 수 있으며 주요 진료 대상은 갑상선 결절 질환 환자들이다. 갑상선 결절의 진단은 일차적으로 초음파 영상진단과 생검에 의해서 이루어지고 결절의 치료는 비수술적 중재적 치료와 갑상선절제술이다. 갑상선 낭종 혹은 낭성우세 양성 결절에서는 에탄올절제술이 일차적 치료법이고 고주파절제술은 고형 혹은 고형우세 양성 결절과 갑상선 재발암 치료에 적용되고 있다. 갑상선 영상의학 진료는 갑상선 결절 질환 환자의 진단 및 비수술적 치료의 대부분을 담당하는 중요한 임상적 역할을 가지고 있으며, 적절한 환자 진료를 위해서는 표준적 진료 지침에 근거하여 진료가 수행되어야 한다. 환자에게 최적의 갑상선 영상의학 진료를 제공하기 위해서는 영상의학과 외래에서 환자를 진료하는 것이 바람직하며 외래 중심의 갑상선 영상의학 진료를 확대하도록 함께 노력해야 할 시점이다.

• Korean Journal of Radiology
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• 제25권3호
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• pp.301-313
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• 2024

Objective: The current body of evidence lacks clarity regarding the comparative efficacy and safety of radiofrequency ablation (RFA) and microwave ablation (MWA) as minimally invasive treatments for benign thyroid nodules. The primary objective of this study is to clarify these concerns. Materials and Methods: A comprehensive search was conducted using the Cochrane Library, Scopus, Europe PMC, and Medline databases until October 10th, 2023, using a combination of relevant keywords. This study incorporated literature that compared RFA and MWA for benign thyroid nodules. The primary outcome was the volume reduction ratio (VRR) from baseline to follow-up. Secondary outcomes were symptom score, cosmetic score, ablation time, major complications rate, hemorrhage, hoarseness, skin burn, cough, and sympathetic nerve injury. We used Risk of Bias in Non-randomized Studies - of Interventions (ROBINS-I) tool to assess the risk of bias in the included studies. We employed random effects models to analyze the standardized mean difference (SMD) and odds ratio for the presentation of outcomes. Results: Nine studies with 2707 nodules were included. The results of our meta-analysis indicated similar efficacy between RFA and MWA in terms of VRR during the 1 (SMD 0.06; 95% confidence interval [CI]: -0.13 to 0.26; P = 0.52) and 3 (SMD 0.11; 95% CI: -0.03 to 0.25; P = 0.12) months of follow-up. VRR was significantly higher in RFA than in MWA at the 6 (SMD 0.25; 95% CI: 0.06-0.43; P = 0.008) and 12 month of follow-up (SMD 0.38; 95% CI: 0.17 to 0.59; P < 0.001). There were no significant differences between RFA and MWA in symptom scores, cosmetic scores, or the incidence of complications, including hemorrhage, hoarseness, skin burn, cough, and sympathetic nerve injury. Conclusion: RFA showed a higher VRR than MWA at 6 and 12-month follow-ups, with a comparable safety profile.

• Korean Journal of Radiology
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• 제24권2호
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• pp.86-94
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• 2023

Objective: To compare Octopus multipurpose (MP) electrodes, which are capable of saline instillation and direct tissue temperature measurement, and conventional electrodes for radiofrequency ablation (RFA) in porcine livers in vivo. Materials and Methods: Sixteen pigs were used in this study. In the first experiment, RFA was performed in the liver for 6 minutes using Octopus MP electrodes (n = 15 ablation zones) and conventional electrodes (n = 12 ablation zones) to investigate the effect of saline instillation. The ablation energy, electrical impedance, and ablation volume of the two electrodes were compared. In the second experiment, RFA was performed near the gallbladder (GB) and colon using Octopus MP electrodes (n = 12 ablation zones for each) with direct tissue temperature monitoring and conventional electrodes (n = 11 ablation zones for each). RFA was discontinued when the temperature increased to > 60℃ in the Octopus MP electrode group, whereas RFA was performed for a total of 6 minutes in the conventional electrode group. Thermal injury was assessed and compared between the two groups by pathological examination. Results: In the first experiment, the ablation volume and total energy delivered in the Octopus MP electrode group were significantly larger than those in the conventional electrode group (15.7 ± 4.26 cm³ vs. 12.5 ± 2.14 cm³, p = 0.027; 5.48 ± 0.49 Kcal vs. 5.04 ± 0.49 Kcal, p = 0.029). In the second experiment, thermal injury to the GB and colon was less frequently noted in the Octopus MP electrode group than that in the conventional electrode group (16.7% [2/12] vs. 90.9% [10/11] for GB and 8.3% [1/12] vs. 90.9% [10/11] for colon, p < 0.001 for all). The total energy delivered around the GB (2.65 ± 1.07 Kcal vs. 5.04 ± 0.66 Kcal) and colon (2.58 ± 0.57 Kcal vs. 5.17 ± 0.90 Kcal) were significantly lower in the Octopus MP electrode group than that in the conventional electrode group (p < 0.001 for all). Conclusion: RFA using the Octopus MP electrodes induced a larger ablation volume and resulted in less thermal injury to the adjacent organs compared with conventional electrodes.