• Journal of the Korean Society of Radiology
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• v.84 no.5
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• pp.999-1008
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• 2023

Thyroid cancer, characterized by high incidence rates, good prognosis, and frequent recurrence, is typically treated surgically. However, since the early 2000s, radiofrequency ablation, which is commonly utilized in liver, lung, and kidney cancers, is being performed for management of primary and recurrent thyroid cancers. Many studies have focused on inoperable cases of low-risk papillary microcarcinoma (≤ 1 cm) and some have investigated its role in larger lesions (up to 4 cm). Overall, these studies have reported positive results. Radiofrequency ablation for recurrent cancer has primarily been performed for locally recurrent cervical cancer, and this therapeutic approach has been attempted for treatment of distant metastases in lungs and bones, with encouraging outcomes. A growing global trend, particularly in South Korea, the United States, and Europe supports radiofrequency ablation for thyroid cancer. However, this therapy is currently not recognized as a treatment option recommended by universally accepted clinical guidelines such as those established by the National Comprehensive Cancer Network. Based on past efforts and future research, radiofrequency ablation is expected to play a key role in thyroid cancer treatment in the near future.

• International Journal of Arrhythmia
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• v.19 no.3
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• pp.186-234
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• 2018

Catheter and surgical ablation of atrial fibrillation (AF) have evolved from investigational procedures to their current role as effective treatment options for patients with AF. Surgical ablation of AF is available in most major hospitals throughout the world. Catheter ablation of AF is even more widely available, and is now the most commonly performed catheter ablation procedure. Management of patients with AF has traditionally consisted of three main components: (1) anticoagulation for stroke prevention; (2) rate control; and (3) rhythm control. With the emergence of large amounts of data, which have both defined and called attention to the interaction between modifiable risk factors and the development of AF and outcomes of AF management, we believe it is time to include risk factor modification as the fourth pillar of AF management. Catheter and surgical ablation of AF are highly complex procedures, therefore a decision to perform catheter or surgical AF ablation should only be made after a patient carefully considers the risks, benefits, and alternatives to the procedure.

• Journal of Medicine and Life Science
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• v.19 no.3
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• pp.95-102
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• 2022

This retrospective study aimed to investigate whether there was a difference in the success rate of removal of residual thyroid tissue in patients with the same cutoff serum thyroglobulin (Tg) value-measured 2 weeks after thyroid hormone withdrawal (THW)-for different radioactive iodine (RAI) activities. We identified 132 patients with papillary thyroid cancer who were treated with total thyroidectomy and RAI therapy to evaluate the efficacy of three radioactivities of I-131: 1,110, 3,700, and 5,550 MBq. Serum Tg testing was performed 1 week before RAI treatment and 2 weeks after THW (pre-Tg); the cutoff pre-Tg level was below 10 ng/mL. Stimulated Tg levels were measured on the day of I-131 administration (off-Tg). After 6 months of treatment, we compared the groups for complete ablation, defined as no uptake on a diagnostic I-131 scan, stimulated Tg level of <1.0 ng/mL, and Tg antibody level of <100 ng/mL. Ninety-five patients (72.0%) achieved complete ablation, with 57.1% (8/14), 78.2% (68/87), and 61.3% (19/31) in the 1,110 MBq, 3,700 MBq, and 5,550 MBq groups, respectively. There was no significant difference in the complete ablation rates between the three groups. In the multivariate analysis, the off-Tg level was a significant predictor of complete ablation. RAI therapy with low radioactivity (1,110 MBq) seemed sufficient for ablation in patients with papillary thyroid cancer with a pre-Tg level below 10 ng/mL. The off-Tg level is a promising and useful predictor of complete ablation after initial RAI therapy.

• Korean Circulation Journal
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• v.52 no.10
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• pp.755-767
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• 2022

Background and Objectives: Cryoballoon catheter ablation for the treatment of patients with symptomatic atrial fibrillation (AF) has been adopted globally, but there are limited multicenter reports of 12-month outcomes in the Korean patient population. This analysis evaluated the clinical performance and safety of cryoballoon ablation (CBA) according to standard-of-care practices in Korea. Methods: This evaluation of Korean patients with AF was conducted within the larger Cryo Global Registry, which is a prospective, multicenter, post-market registry. Freedom from a ≥30-second recurrence of atrial arrhythmias (after a 90-day blanking period until 12 months) and procedural safety were examined in subjects treated with CBA at 3 Korean centers. Results: Overall, 299 patients with AF (60±11 years old, 24.7% female, 50.5% paroxysmal AF) underwent CBA using the Arctic Front Advance cryoballoon. Of those, 298 were followed-up for at least 12 months. Mean procedure-, left atrial dwell- and fluoroscopy time was 76±21 minutes, 56±23 minutes, and 27±23 minutes, respectively. Freedom from AF recurrence at 12 months was 83.9% (95% confidence interval [CI], 76.9-88.9%) in the paroxysmal and 61.6% (95% CI, 53.1-69.0%) in the persistent AF cohort. Rhythm monitoring was performed on average 4.7±1.4 times during the follow-up period. Serious device- or procedure-related adverse events occurred in 2 patients (0.7%). The 12-month Kaplan-Meier estimate of freedom from repeat ablation and cardiovascular-related hospitalization was 93.8% (95% CI, 90.4-96.1%) and 89.7% (95% CI, 85.6-92.7%), respectively. Conclusions: CBA is an efficient, effective, and safe procedure for the treatment of AF patients when used according to real-world practices in Korea.

• International Journal of Computer Science & Network Security
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• v.23 no.2
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• pp.183-192
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• 2023

Radiofrequency ablation (RFA) is an alternative treatment for liver cancer to the surgical intervention preferred by surgeons. However, the main challenge remains the use of RF for the ablation of large tumours (i.e., tumours with a diameter of >3 cm). For large tumours, RFA takes a large duration in the ablation process compared with surgery, which increases patient pain. Therefore, RFA for large tumours is not preferred by surgeons. The currently materials used in RF electrodes, such as the nickeltitanium alloy (nitinol), are characterized by low thermal and electrical conductivities. On the other hand, the use of materials that have high thermal and electrical conductivities, such as titanium aluminide alloy (gamma titanium), produces more thermal energy for tumours. In this paper, we developed a cool-tip RF electrode model that uses nickel-titanium alloy and replaced it with titanium aluminide alloy by using the finite element model (FEM). The aim of this paper is to study the effect of the thermal and electrical conductivities of gamma titanium on the ablation volume. Results showed that the proposed design of the electrode increased the ablation rate by 1 cm³ /minute and 6.3 cm³/10 minutes, with a decrease in the required time ablation. Finally, the proposed model reduces the ablation time and damages healthy tissue while increasing the ablation volume from 22.5% cm³ to 62.5% cm³ in ten minutes compared to recent studies.

• Journal of Chest Surgery
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• v.51 no.4
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• pp.290-292
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• 2018

Radiofrequency ablation is an effective treatment for atrial fibrillation. Pulmonary vein stenosis/occlusion is one of its rare complications. Herein, the case of a 50-year-old man with hemoptysis and migratory pulmonary infiltrations after transcatheter radiofrequency ablation for atrial fibrillation is presented. Initially, pneumonia, interstitial pulmonary disease, or lung cancer was suspected, but wedge resection revealed hemorrhagic infiltrations. Chest computed tomography pulmonary angiography detected no left superior pulmonary vein due to its total occlusion, and left upper lobectomy was performed. Post-ablation pulmonary vein occlusion must be strongly suspected in cases of migratory pulmonary infiltrations and/or hemoptysis.

• Korean Circulation Journal
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• v.53 no.5
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• pp.273-293
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• 2023

Pulsed field ablation (PFA) was recently rediscovered as an emerging treatment modality for the ablation of cardiac arrhythmias. Ultra-short high voltage pulses are leading to irreversible electroporation of cardiac cells subsequently resulting in cell death. Current literature of PFA for pulmonary vein isolation (PVI) consistently reported excellent acute and long-term efficacy along with a very low adverse event rate. The undeniable benefit of the novel ablation technique is that cardiac cells are more susceptible to electrical fields whereas surrounding structures such as the pulmonary veins, the phrenic nerve or the esophagus are not, or if at all, minimally affected, which results in a favorable safety profile that is expected to be superior to the current standard of care without compromising efficacy. Nevertheless, the exact mechanisms of electroporation are not yet entirely understood on a cellular basis and pulsed electrical field protocols of different manufactures are not comparable among one another and require their own validation for each indication. Importantly, randomized controlled trials and comparative data to current standard of care modalities, such as radiofrequency- or cryoballoon ablation, are still missing. This review focuses on the "pearls" and "pitfalls" of PFA, a technology that has the potential to become the future leading energy source for PVI and beyond.

• Korean Journal of Radiology
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• v.22 no.2
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• pp.179-188
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• 2021

Objective: This study aimed to prospectively compare the efficacy, safety, and mid-term outcomes of dual-switching monopolar (DSM) radiofrequency ablation (RFA) to those of conventional single-switching monopolar (SSM) RFA in the treatment of hepatocellular carcinoma (HCC). Materials and Methods: This single-center, two-arm, parallel-group, randomized controlled study was approved by the Institutional Review Board. Written informed consent was obtained from all patients upon enrollment. A total of 80 patients with 94 HCC nodules were randomized into either the DSM-RFA group or SSM-RFA group in a 1:1 ratio, using a blocked randomization method (block size 2). The primary endpoint was the minimum diameter of the ablation zone per unit time. The secondary endpoints included other technical parameters, complication rate, technique efficacy, and 2-year clinical outcomes. Results: Significantly higher ablation energy per unit time was delivered to the DSM-RFA group than to the SSM-RFA group (1.7 ± 0.2 kcal/min vs. 1.2 ± 0.3 kcal/min; p < 0.001). However, no significant differences were observed between the two groups for the analyzed variables, including primary endpoint, regarding size of the ablation zone and ablation time. Major complication rates were 4.9% in the DSM-RFA group and 2.6% in the SSM-RFA group (p = 1.000). The 2-year local tumor progression (LTP) rates of the HCC nodules treated using DSM-RFA and SSM-RFA were 8.5% and 4.7%, respectively (p = 0.316). The 2-year LTP-free survival rates of patients in the DSM-RFA and SSM-RFA groups were 90.0% and 94.4%, respectively (p = 0.331), and the 2-year recurrence-free survival rates were 54.9% and 75.7%, respectively (p = 0.265). Conclusion: Although DSM-RFA using a separable clustered electrode delivers higher ablation energy than SSM-RFA, its effectiveness failed to show superiority over SSM-RFA in the treatment of HCC.

• Journal of Convergence Korean Medicine
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• v.1 no.1
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• pp.35-44
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• 2021

Objectives: The purpose of this study is to investigate the effect of ultrasound therapy on left knee pain and instability diagnosed with Baker's cyst in a 25-year-old male patient. Methods: Patient was treated with Radio frequency ablation treatment on left knee from Naeseulan (EX-LE4) to Wijoong (BL40). The effect of radio frequency ablation was assessed by Visual Analog Scale (VAS), Western Ontario and McMaster Universities (WOMAC) and Euro Qol-5 Dimension Index (EQ-5D Index). The treatment was executed one time a day everyday form May 28th to June 1st of 2020. Patient was observed from May 26th to June 1st. Results: After five sessions of radio frequency ablation, VAS of left posterior knee pain was improved while no improvement was discovered at left medial knee. In Korean WOMAC scale, only subscale of weight bearing and walking around plain were improved. EQ-5D did not show any improvement. Conclusion: The results suggest that radio frequency ablation treatment can be a valuable option in treating knee pain and daily living function. Further study seems to be needed based on long-term intervention.