• Korean Journal of Radiology
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• v.22 no.10
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• pp.1730-1741
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• 2021

Objective: Although thermal ablation is effective in treating low-risk papillary thyroid microcarcinomas (PTMCs), comparison of treatment outcomes between thermal ablation and surgery has not yet been systematically evaluated. This study aimed to compare the efficacy and safety of thermal ablation and surgery for the treatment of low-risk PTMCs. Materials and Methods: Ovid-MEDLINE and EMBASE databases were searched for studies reporting comparisons of treatment results between thermal ablation and surgery for patients with low-risk PTMC published up to April 6, 2020. The analysis evaluated the efficacy (local tumor recurrence, occurrence of new tumor, metastasis, and rescue surgery) and safety (complication rate) of thermal ablation and surgery. Results: This systematic review included four studies with a total of 339 PTMCs in 339 patients who underwent thermal ablation and 320 PTMCs in 314 patients who underwent surgery. There was no local tumor recurrence or distant metastasis in either group. There was no significant difference in the pooled proportion of lymph node metastasis (2.6% with thermal ablation vs. 3.3% with surgery, p = 0.65), occurrence of new tumors (1.4% with thermal ablation vs. 1.3% with surgery, p = 0.85), or rescue surgery (2.6% with thermal ablation vs. 1.6% with surgery, p = 0.62). However, the pooled complication rate was significantly higher in the surgery group than in the ablation group (3.3% with thermal ablation vs. 7.8% with surgery, p = 0.03). Conclusion: Both thermal ablation and surgery are effective and safe options for the management of low-risk PTMCs, with thermal ablation achieving a lower complication rate. Therefore, thermal ablation may be considered as an alternative treatment option for low-risk PTMC in patients who refuse surgery and active surveillance or are ineligible for surgery.

• Journal of the Korean Physical Society
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• v.73 no.11
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• pp.1619-1624
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• 2018

Laser ablation may provide a minimally invasive palliative treatment for pancreatic cancer. The aim of the current study was to assess the feasibility of a 532-nm laser equipped with a cylindrical light diffuser for the treatment of pancreatic cancer. Monolayers of BxPC-3 human pancreatic cancer cell were exposed to 532 nm laser light. Power levels of 5 - 7 W were used to uniformly target the entire cell colonies for 60 and 120 seconds. The cells were incubated for 24 hours after treatment and viabilities were determined by using a MTT assay. Laser ablation was performed by using the cylindrical light diffuser on six pancreatic tumor tissues obtained from pancreatic cancer xenograft mouse models, which were exposed to the 532 nm light at 5W or 7W for 10 to 30 seconds. In the in vitro study, the survival rates of the pancreatic cancer cells were reduced by 6.6% to 98.9% after the treatment, and the survival rates were reduced by increasing laser power and/or irradiation time. In the pancreatic tumor tissues, a homogenous circular ablation zone was observed in all tumors and the ablation distance induced by the laser irradiation showed to be constant from the diffuser to all directions (standard deviation, 0.3 - 1.3 mm). Ablation distance and area increased with increasing laser power and/or irradiation time. The 532 nm laser effectively killed pancreatic cancer cells, and the cylindrical light diffuser was found to be suitable for laser ablation as it provided uniform ablation in pancreatic cancer.

• Korean Journal of Radiology
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• v.25 no.9
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• pp.773-787
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• 2024

Local ablation for hepatocellular carcinoma (HCC), a non-surgical option that directly targets and destroys tumor cells, has advanced significantly since the 1990s. Therapies with different energy sources, such as radiofrequency ablation, microwave ablation, and cryoablation, employ different mechanisms to induce tumor necrosis. The precision, safety, and effectiveness of these therapies have increased with advances in guiding technologies and device improvements. Consequently, local ablation has become the first-line treatment for early-stage HCC. The lack of organized evidence and expert opinions regarding patient selection, pre-procedure preparation, procedural methods, swift post-treatment evaluation, and follow-up has resulted in clinicians following varied practices. Therefore, an expert consensus-based practical recommendation for local ablation was developed by a group of experts in radiology and hepatology from the Research Committee of the Korean Liver Cancer Association in collaboration with the Korean Society of Image-guided Tumor Ablation to provide useful information and guidance for performing local ablation and for the pre- and post-treatment management of patients.

• 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 Yeungnam Medical Science
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• v.41 no.4
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• pp.279-287
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• 2024

Atrial fibrillation (AF) is the most common sustained tachyarrhythmia and its increasing prevalence has resulted in a growing health-care burden. A recent landmark randomized trial, the EAST-AFNET 4 (Early Treatment of Atrial Fibrillation for Stroke Prevention Trial), highlighted the importance of early rhythm control in AF, which was previously underemphasized. Rhythm control therapy includes antiarrhythmic drugs, direct-current cardioversion, and catheter ablation. Currently, catheter ablation is indicated for patients with AF who are either refractory or intolerant to antiarrhythmic drugs or who exhibit decreased left ventricular systolic function. Catheter ablation can be categorized according to the energy source used, including radiofrequency ablation (RFA), cryoablation, laser ablation, and the recently emerging pulsed field ablation (PFA). Catheter ablation techniques can also be divided into the point-by-point ablation method, which ablates the pulmonary vein (PV) antrum one point at a time, and the single-shot technique, which uses a spherical catheter to ablate the PV antrum in a single application. PFA is known to be applicable to both point-by-point and single-shot techniques and is expected to be promising owing to its tissue specificity, resulting in less collateral damage than catheter ablation involving thermal energy, such as RFA and cryoablation. In this review, we aimed to outline catheter ablation for rhythm control in AF by reviewing previous studies.

• Clinical Endoscopy
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• v.55 no.3
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• pp.347-354
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• 2022

Referral to an endoscopist is often done once curative resection is no longer an option for cholangiocarcinoma management. In such cases, palliation has become the main objective of the treatment. Photodynamic therapy and radiofrequency ablation can be performed to achieve palliation, with both procedures associated with improved stent patency and survival. Despite the greatly increased cost and association with photosensitivity, photodynamic therapy allows transmission to the entire biliary tree. In contrast, radiofrequency ablation is cheaper and faster to apply, but requires intraductal contact. This paper reviews both modalities and compares their efficacy and safety for bile duct cancer palliation.

• Laser Solutions
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• v.6 no.3
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• pp.37-45
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• 2003

Pulsed laser ablation is important in a variety of engineering applications involving precise removal of materials in laser micromachining and laser treatment of bio-materials. Particularly, detailed numerical simulation of complex laser ablation phenomena in air, taking the interaction between ablation plume and air into account, is required for many practical applications. In this paper, high-power pulsed laser ablation under atmospheric pressure is studied with emphasis on the vaporization model, especially recondensation ratio over the Knudsen layer. Furthermore, parametric studies are carried out to analyze the effect of laser fluence and background pressure on surface ablation and the dynamics of ablation plume. In the numerical calculation, the temperature, pressure, density, and vaporization flux on a solid substrate are obtained by a heat-transfer computation code based on the enthalpy method. The plume dynamics is calculated considering the effect of mass diffusion into the ambient air and plasma shielding. To verify the computation results, experiments for measuring the propagation of a laser induced shock wave are conducted as well.

• International Journal of Arrhythmia
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• v.19 no.3
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• pp.285-339
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• 2018

Catheter ablation of atrial fibrillation (AF) is one of the most complex interventional electrophysiological procedures. The success of AF ablation is based in large part on freedom from AF recurrence based on electrocardiography (ECG) monitoring. Arrhythmia monitoring can be performed with the use of noncontinuous or continuous ECG monitoring tools. AF ablation is an invasive procedure that entails risks, most of which are present during the acute procedural period. However, complications can also occur in the weeks or months following ablation. Recognizing common symptoms after AF ablation and distinguishing those that require urgent evaluation and referral to an electrophysiologist is an important part of follow-up after AF ablation. This section reviews the complications associated with catheter ablation procedures performed to treat AF. The types and incidence of complications are presented, their mechanisms are explored, and the optimal approach to prevention and treatment is discussed. Finally, surgical and hybrid AF ablation technology and the indications for concomitant open or closed surgical ablation of AF, stand-alone and hybrid surgical ablation of AF are covered in this section.

• Journal of Chest Surgery
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• v.29 no.12
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• pp.1373-1376
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• 1996

From October 1993 to February 1996, 9 patients with Wolfr-Parkinson-White syndrome underwent surgical ablation of the accessory atrioventricular conduction pathways. The indications for surgical ablation we e radiofrequency ablation failure in 6 cases, multiple accessory pathways in 1 case, catheter tip fracture ducting catheter ablation in 1 case and additional procedure(redo mitral valve replacement due to valve thrombosis) in 1 case. There was no operative mortality. The postoperative complications were noted In 2 cases pericardial effusion and wound Infection. All patients had accessory atrioventricular connections ablated which were proven by surface ECG and follow-up electrophysiologic study and have remained free of symptomatic tachycardia. The indications for surgical treatment of Wolff-Parkinson-White syndrome are radiofrequency ablation failure, multiple pathways, or when additional procedures are required The present results were satisfactory.

• Korean Journal of Radiology
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• v.20 no.5
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• pp.695-708
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• 2019

Atrial fibrillation (AF) is the most common arrhythmia associated with the risk of morbidity and mortality in clinical patients. AF is considered as an arrhythmia type that develops and progresses through close connection with cardiac structural arrhythmogenic substrates. Since the introduction of catheter ablation-mediated electrical isolation of arrhythmogenic substrates, cardiac imaging indicates improved treatment outcome and prognosis with appropriate candidate selection, ablation catheter guidance, and post-ablation follow-up. Currently, cardiac computed tomography (CCT) and cardiovascular magnetic resonance (CMR) imaging are essential in the case management of AF at both pre-and post-procedural stages of catheter ablation. In this review, we discuss the roles and technical considerations of CCT and CMR imaging in the management of patients with AF undergoing catheter ablation.