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Sample records for tumors thermal ablation

  1. Radiofrequency thermal ablation of malignant hepatic tumors: post-ablation syndrome

    International Nuclear Information System (INIS)

    Choi, Jung Bin; Rhim, Hyunchul; Kim, Yongsoo; Koh, Byung Hee; Cho, On Koo; Seo, Heung Suk; Lee, Seung Ro

    2000-01-01

    To evaluate post-ablation syndrome after radiofrequency thermal ablation of malignant hepatic tumors. Forty-two patients with primary (n=3D29) or secondary (n=3D13) hepatic tumors underwent radiofrequency thermal ablation. A total of 65 nodules ranging in size from 1.1 to 5.0 (mean, 3.1) cm were treated percutaneously using a 50W RF generator with 15G expandable needle electrodes. We retrospectively evaluated the spectrum of post-ablation syndrome including pain, fever (≥3D 38 deg C), nausea, vomiting, right shoulder pain, and chest discomfort according to frequency, intensity and duration, and the findings were correlated with tumor location and number of ablations. We also evaluated changes in pre-/post-ablation serum aminotransferase (ALT/AST) and prothrombin time, and correlated these findings with the number of ablations. Post-ablation syndrome was noted in 29 of 42 patients (69.0%), and most symptoms improved with conservative treatment. The most important of these were abdominal plan (n=3D20, 47.6%), fever (n=3D8, 19.0%), and nausea (n=3D7, 16.7%), and four of 42 (9.5%) patients complained of severe pain. The abdominal pain lasted from 3 hours to 5.5 days (mean; 20.4 hours), the fever from 6 hours to 5 days (mean; 63.0 hours). And the nausea from 1 hours to 4 days (mean; 21.0 hours). Other symptoms were right shoulder pain (n=3D6, 14.3%), chest discomfort (n=3D3, 7.1%), and headache (n=3D3, 7.1%). Seventeen of 20 patients (85%) with abdominal pain had subcapsular tumor of the liver. There was significant correlation between pain, location of the tumor, and a number of ablations. After ablation, ALT/AST was elevated more than two-fold in 52.6%/73.7% of patients, respectively but there was no significant correlation with the number of ablation. Post-ablation syndrome is a frequent and tolerable post-procedural process after radiofrequency thermal ablation. The spectrum of this syndrome provides a useful guideline for the post-ablation management. (author)

  2. Percutaneous treatment of bone tumors by radiofrequency thermal ablation

    International Nuclear Information System (INIS)

    Ruiz Santiago, Fernando; Mar Castellano Garcia, Maria del; Guzman Alvarez, Luis; Martinez Montes, Jose Luis; Ruiz Garcia, Manuel; Tristan Fernandez, Juan MIguel

    2011-01-01

    We present our experience of the treatment of bone tumors with radiofrequency thermal ablation (RFTA). Over the past 4 years, we have treated 26 cases (22 benign and 4 malignant) using CT-guided RFTA. RFTA was the sole treatment in 19 cases and was combined with percutaneous cementation during the same session in the remaining seven cases. Our approach to the tumors was simplified, using a single point of entrance for both RFTA and percutaneous osteoplasty. In the benign cases, clinical success was defined as resolution of pain within 1 month of the procedure and no recurrence during the follow-up period. It was achieved in 19 out of the 21 patients in which curative treatment was attempted. The two non-resolved cases were a patient with osteoid osteoma who developed a symptomatic bone infarct after a symptom-free period of 2 months and another with femoral diaphysis osteoblastoma who suffered a pathological fracture after 8 months without symptoms. The procedure was considered clinically successful in the five cases (4 malign and 1 benign) in which palliative treatment was attempted, because there was a mean (±SD) reduction in visual analogue scale (VAS) pain score from 9.0 ± 0.4 before the procedure to <4 during the follow-up period.

  3. Percutaneous treatment of bone tumors by radiofrequency thermal ablation

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Santiago, Fernando, E-mail: ferusan@ono.com [Department of Radiology, Hospital of Traumatology (Ciudad Sanitaria Virgen de las Nieves), Carretera de Jaen SN, 18013 Granada (Spain); Mar Castellano Garcia, Maria del; Guzman Alvarez, Luis [Department of Radiology, Hospital of Traumatology (Ciudad Sanitaria Virgen de las Nieves), Carretera de Jaen SN, 18013 Granada (Spain); Martinez Montes, Jose Luis [Department of Traumatology, Hospital of Traumatology (Ciudad Sanitaria Virgen de las Nieves), Carretera de Jaen SN, 18013 Granada (Spain); Ruiz Garcia, Manuel; Tristan Fernandez, Juan MIguel [Department of Radiology, Hospital of Traumatology (Ciudad Sanitaria Virgen de las Nieves), Carretera de Jaen SN, 18013 Granada (Spain)

    2011-01-15

    We present our experience of the treatment of bone tumors with radiofrequency thermal ablation (RFTA). Over the past 4 years, we have treated 26 cases (22 benign and 4 malignant) using CT-guided RFTA. RFTA was the sole treatment in 19 cases and was combined with percutaneous cementation during the same session in the remaining seven cases. Our approach to the tumors was simplified, using a single point of entrance for both RFTA and percutaneous osteoplasty. In the benign cases, clinical success was defined as resolution of pain within 1 month of the procedure and no recurrence during the follow-up period. It was achieved in 19 out of the 21 patients in which curative treatment was attempted. The two non-resolved cases were a patient with osteoid osteoma who developed a symptomatic bone infarct after a symptom-free period of 2 months and another with femoral diaphysis osteoblastoma who suffered a pathological fracture after 8 months without symptoms. The procedure was considered clinically successful in the five cases (4 malign and 1 benign) in which palliative treatment was attempted, because there was a mean ({+-}SD) reduction in visual analogue scale (VAS) pain score from 9.0 {+-} 0.4 before the procedure to <4 during the follow-up period.

  4. More Than Just Tumor Destruction: Immunomodulation by Thermal Ablation of Cancer

    Directory of Open Access Journals (Sweden)

    Sebastian P. Haen

    2011-01-01

    Full Text Available Over the past decades, thermoablative techniques for the therapy of localized tumors have gained importance in the treatment of patients not eligible for surgical resection. Anecdotal reports have described spontaneous distant tumor regression after thermal ablation, indicating a possible involvement of the immune system, hence an induction of antitumor immunity after thermoinduced therapy. In recent years, a growing body of evidence for modulation of both adaptive and innate immunity, as well as for the induction of danger signals through thermoablation, has emerged. Induced immune responses, however, are mostly weak and not sufficient for the complete eradication of established tumors or durable prevention of disease progression, and combination therapies with immunomodulating drugs are being evaluated with promising results. This article aims to summarize published findings on immune modulation through radiofrequency ablation, cryoablation, microwave ablation therapy, high-intensity focused ultrasound, and laser-induced thermotherapy.

  5. Optical fiber biocompatible sensors for monitoring selective treatment of tumors via thermal ablation

    Science.gov (United States)

    Tosi, Daniele; Poeggel, Sven; Dinesh, Duraibabu B.; Macchi, Edoardo G.; Gallati, Mario; Braschi, Giovanni; Leen, Gabriel; Lewis, Elfed

    2015-09-01

    Thermal ablation (TA) is an interventional procedure for selective treatment of tumors, that results in low-invasive outpatient care. The lack of real-time control of TA is one of its main weaknesses. Miniature and biocompatible optical fiber sensors are applied to achieve a dense, multi-parameter monitoring, that can substantially improve the control of TA. Ex vivo measurements are reported performed on porcine liver tissue, to reproduce radiofrequency ablation of hepatocellular carcinoma. Our measurement campaign has a two-fold focus: (1) dual pressure-temperature measurement with a single probe; (2) distributed thermal measurement to estimate point-by-point cells mortality.

  6. Thermal and mechanical high-intensity focused ultrasound: perspectives on tumor ablation, immune effects and combination strategies.

    Science.gov (United States)

    van den Bijgaart, Renske J E; Eikelenboom, Dylan C; Hoogenboom, Martijn; Fütterer, Jurgen J; den Brok, Martijn H; Adema, Gosse J

    2017-02-01

    Tumor ablation technologies, such as radiofrequency-, cryo- or high-intensity focused ultrasound (HIFU) ablation will destroy tumor tissue in a minimally invasive manner. Ablation generates large volumes of tumor debris in situ, releasing multiple bio-molecules like tumor antigens and damage-associated molecular patterns. To initiate an adaptive antitumor immune response, antigen-presenting cells need to take up tumor antigens and, following activation, present them to immune effector cells. The impact of the type of tumor ablation on the precise nature, availability and suitability of the tumor debris for immune response induction, however, is poorly understood. In this review, we focus on immune effects after HIFU-mediated ablation and compare these to findings using other ablation technologies. HIFU can be used both for thermal and mechanical destruction of tissue, inducing coagulative necrosis or subcellular fragmentation, respectively. Preclinical and clinical results of HIFU tumor ablation show increased infiltration and activation of CD4 + and CD8 + T cells. As previously observed for other types of tumor ablation technologies, however, this ablation-induced enhanced infiltration alone appears insufficient to generate consistent protective antitumor immunity. Therapies combining ablation with immune stimulation are therefore expected to be key to boost HIFU-induced immune effects and to achieve systemic, long-lasting, antitumor immunity.

  7. Radiofrequency Ablation of Lung Tumors

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Radiofrequency Ablation (RFA) / Microwave Ablation (MWA) of Lung Tumors ... and Microwave Ablation of Lung Tumors? What are Radiofrequency and Microwave Ablation of Lung Tumors? Radiofrequency ablation, ...

  8. Tumor lysis syndrome following endoscopic radiofrequency interstitial thermal ablation of colorectal liver metastases.

    LENUS (Irish Health Repository)

    Barry, B D

    2012-02-03

    Radiofrequency interstitial thermal ablation (RITA) provides a palliative option for patients suffering from metastatic liver disease. This procedure can be performed using a laparoscopic approach with laparoscopic ultrasound used to position the RITA probe. We describe a case of laparoscopic RITA performed for colorectal liver metastasis that was complicated by tumor lysis syndrome (TLS) following treatment. We consider RITA to be a safe procedure, as supported by the literature, but where intracorporal tumor lysis is the treatment goal we believe that the systemic release of tumor products can overwhelm the excretory capacity; therefore, TLS is an inevitable consequence in some patients.

  9. Thermal ablation of intrahepatic cholangiocarcinoma: Safety, efficacy, and factors affecting local tumor progression.

    Science.gov (United States)

    Takahashi, Edwin A; Kinsman, Kristin A; Schmit, Grant D; Atwell, Thomas D; Schmitz, John J; Welch, Brian T; Callstrom, Matthew R; Geske, Jennifer R; Kurup, A Nicholas

    2018-06-04

    To evaluate the safety and oncologic efficacy of percutaneous thermal ablation of intrahepatic cholangiocarcinoma (ICC) and identify risk factors for local tumor progression (LTP). Retrospective review of an institutional tumor ablation registry demonstrated that 20 patients (9 males, 11 females; mean age 62.5 ± 15.8 years) with 50 ICCs (mean size 1.8 ± 1.3 cm) were treated with percutaneous radiofrequency ablation (RFA) or microwave ablation (MWA) between 2006 and 2015. Thirty-eight of the treated ICCs (76%) were metastases that developed after surgical resection of the primary tumor. Patient demographics, procedure technical parameters, and clinical outcomes were reviewed. A Cox proportional hazards model was used to examine the risk of LTP by ablation modality. Survival analyses were performed using the Kaplan-Meier method. Mean imaging follow-up time was 41.5 ± 42.7 months. Forty-four (88%) ICCs were treated with RFA, and 6 (12%) with MWA. Eleven (22%) cases of LTP developed in 5 (25%) patients. The median time to LTP among these 11 tumors was 7.1 months (range, 2.3-22.9 months). Risk of LTP was not significantly different for ICCs treated with MWA compared to RFA (HR 2.72; 95% CI 0.58-12.84; p = 03.21). Median disease-free survival was 8.2 months (1.1-70.4 months), and median overall survival was 23.6 months (7.4-122.5 months). No major complication occurred. Percutaneous thermal ablation is a safe and effective treatment for patients with ICCs and may be particularly valuable in unresectable patients, or those who have already undergone hepatic surgery. Tumor size and ablation modality were not associated with LTP, whereas primary tumors and superficially located tumors were more likely to subsequently recur.

  10. Percutaneous radiofrequency thermal ablation of lung VX2 tumors in a rabbit model: evaluation with helical CT findings for the complete and partal ablation

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Gong Yong; Han, Young Min; Lim, Yeong Su; Jang, Kyu Yun; Lee, Sang Yong; Chung, Gyung Ho [School of Medicine, Chonbuk National Univ., Chonju (Korea, Republic of)

    2004-05-01

    To evaluate the radiologic findings for complete and partial ablation after percutaneous CT-guided transthoracic radiofrequency ablation (RFA) of lung VX2 tumor implanted in rabbits. Thirteen rabbits with successfully implanted lung VX2 were used. Three rabbits as controls did not receive RFA while the other ten rabbits underwent RFA; 5 complete and 5 partial. RFA was performed using an internally cooled, 17-gauge electrode (Radionics, Burlington, MA) with a 1-cm active tip under CT guidance. Postprocedural CT was performed within 3 days, and we analyzed the ablated size, enhancement pattern, shape, margin, and complications of the complete and partial ablation groups. Rabbits were sacrificed after postprocedural CT with an overdose of ketamine, and pathologic findings of the ablated groups were compared with those of the control group. The size of the ablated lesions and the enhancement pattern differed between the completely and partially ablated groups on chest CT. The size of the ablated lesions was increased by 47.1% in the completely ablated group and by 2.1% in the partially ablated group. In the completely ablated group, VX2 tumor showed absolutely no enhancement, whereas only ablated pulmonary parenchyma outside VX2 showed mild enhancement on enhanced CT. In the partial ablated group, a part of VX2 became strongly enhanced on enhanced CT. On microscopic examination, the completely ablated group demonstrated that a viable tumor cell was not visible. In the partially ablated group, however, a viable tumor cell within the surrounding fibrous capsule on the peripheral area of the VX2 was observed. The important CT findings for evaluation of complete and partial RFA are the ablated size and enhancement pattern of the ablated lesion.

  11. Fiber-optic combined FPI/FBG sensors for monitoring of radiofrequency thermal ablation of liver tumors: ex vivo experiments.

    Science.gov (United States)

    Tosi, Daniele; Macchi, Edoardo Gino; Braschi, Giovanni; Cigada, Alfredo; Gallati, Mario; Rossi, Sandro; Poeggel, Sven; Leen, Gabriel; Lewis, Elfed

    2014-04-01

    We present a biocompatible, all-glass, 0.2 mm diameter, fiber-optic probe that combines an extrinsic Fabry-Perot interferometry and a proximal fiber Bragg grating sensor; the probe enables dual pressure and temperature measurement on an active 4 mm length, with 40 Pa and 0.2°C nominal accuracy. The sensing system has been applied to monitor online the radiofrequency thermal ablation of tumors in liver tissue. Preliminary experiments have been performed in a reference chamber with uniform heating; further experiments have been carried out on ex vivo porcine liver, which allowed the measurement of a steep temperature gradient and monitoring of the local pressure increase during the ablation procedure.

  12. Percutaneous thermal ablation of renal neoplasms

    International Nuclear Information System (INIS)

    Tacke, J.; Mahnken, A.H.; Guenther, R.W.

    2005-01-01

    Due to modern examination techniques such as multidetector computed tomography and high-field magnetic resonance imaging, the detection rate of renal neoplasms is continually increasing. Even though tumors exceeding 4 cm in diameter rarely metastasize, all renal lesions that are possible neoplasms should be treated. Traditional treatment techniques include radical nephrectomy or nephron-sparing resection, which are increasingly performed laparoscopically. Modern thermal ablation techniques such as hyperthermal techniques like radiofrequency ablation RFA, laser induced thermal ablation LITT, focused ultrasound FUS and microwave therapy MW, as well as hypothermal techniques (cryotherapy) may be a useful treatment option for patients who are unfit for or refuse surgical resection. Cryotherapy is the oldest and best known thermal ablation technique and can be performed laparoscopically or percutaneously. Since subzero temperatures have no antistyptic effect, additional maneuvers must be performed to control bleeding. Percutaneous cryotherapy of renal tumors is a new and interesting method, but experience with it is still limited. Radiofrequency ablation is the most frequently used method. Modern probe design allows volumes between 2 and 5 cm in diameter to be ablated. Due to hyperthermal tract ablation, the procedure is deemed to be safe and has a low complication rate. Although there are no randomized comparative studies to open resection, the preliminary results for renal RFA are promising and show RFA to be superior to other thermal ablation techniques. Clinical success rates are over 90% for both, cryo- and radiofrequency ablation. Whereas laser induced thermal therapy is established in hepatic ablation, experience is minimal with respect to renal application. For lesions of more than 2 cm in diameter, additional cooling catheters are required. MR thermometry offers temperature control during ablation. Microwave ablation is characterized by small ablation volumes

  13. Risk Factors for Bile Duct Injury After Percutaneous Thermal Ablation of Malignant Liver Tumors: A Retrospective Case-Control Study.

    Science.gov (United States)

    Lin, Man-Xia; Ye, Jie-Yi; Tian, Wen-Shuo; Xu, Ming; Zhuang, Bo-Wen; Lu, Ming-De; Xie, Xiao-Yan; Kuang, Ming

    2017-04-01

    Bile duct injury after ablation of malignant liver tumors (MLTs) was not unusual and should be avoided. However, few studies have focused on evaluating the risk factors for intrahepatic bile duct injury. To evaluate the risk factors for intrahepatic bile duct injury after ablation of MLTs and to evaluate the minimum safe distance for ablating tumors abutting bile ducts. Sixty-five patients with intrahepatic bile duct injury after ablation of MLTs, and 65 controls were recruited. Risk factors for intrahepatic bile duct injury were analyzed. Tumor location was recorded as ≤5 mm (group A), 5-10 mm (group B), and >10 mm (group C) from the right/left main duct or segmental bile duct. Ascites history (P bile duct dilatation before ablation (P bile duct injury. Significant differences in the risk of intrahepatic bile duct injury were found between groups B and C (P = 0.000), but not between groups A and B (P = 0.751). Ascites history (P = 0.002) and tumor location (P Bile duct injury after ablation of MLTs was the result of local treatment-related factors combined with the patients' general condition. The minimum safe distance for ablation of tumor abutting a bile duct was 10 mm.

  14. Ablative thermal protection systems

    International Nuclear Information System (INIS)

    Vaniman, J.; Fisher, R.; Wojciechowski, C.; Dean, W.

    1983-01-01

    The procedures used to establish the TPS (thermal protection system) design of the SRB (solid rocket booster) element of the Space Shuttle vehicle are discussed. A final evaluation of the adequacy of this design will be made from data obtained from the first five Shuttle flights. Temperature sensors installed at selected locations on the SRB structure covered by the TPS give information as a function of time throughout the flight. Anomalies are to be investigated and computer design thermal models adjusted if required. In addition, the actual TPS ablator material loss is to be measured after each flight and compared with analytically determined losses. The analytical methods of predicting ablator performance are surveyed. 5 references

  15. Radiofrequency ablation of pulmonary tumors

    Energy Technology Data Exchange (ETDEWEB)

    Crocetti, Laura, E-mail: l.crocetti@med.unipi.i [Division of Diagnostic Imaging and Intervention, Department of Liver Transplants, Hepatology and Infectious Diseases, Pisa University School of Medicine (Italy); Lencioni, Riccardo [Division of Diagnostic Imaging and Intervention, Department of Liver Transplants, Hepatology and Infectious Diseases, Pisa University School of Medicine (Italy)

    2010-07-15

    The development of image-guided percutaneous techniques for local tumor ablation has been one of the major advances in the treatment of solid tumors. Among these methods, radiofrequency (RF) ablation is currently established as the primary ablative modality at most institutions. RF ablation is accepted as the best therapeutic choice for patients with early-stage hepatocellular carcinoma when liver transplantation or surgical resection are not suitable options and is considered as a viable alternate to surgery for inoperable patients with limited hepatic metastatic disease, especially from colorectal cancer. Recently, RF ablation has been demonstrated to be a safe and valuable treatment option for patients with unresectable or medically inoperable lung malignancies. Resection should remain the standard therapy for non-small cell lung cancer (NSCLC) but RF ablation may be better than conventional external-beam radiation for the treatment of the high-risk individual with NSCLC. Initial favourable outcomes encourage combining radiotherapy and RF ablation, especially for treating larger tumors. In the setting of colorectal cancer lung metastases, survival rates provided by RF ablation in selected patients, are substantially higher than those obtained with any chemotherapy regimens and provide indirect evidence that RF ablation therapy improves survival in patients with limited lung metastatic disease.

  16. Percutaneous tumor ablation in medical radiology

    Energy Technology Data Exchange (ETDEWEB)

    Vogl, T.J.; Mack, M.G. [University Hospital Frankfurt Univ. (Germany). Inst. for Diagnostic and Interventional Radiology; Helmberger, T.K. [Klinikum Bogenhausen, Academic Teaching Hospital of the Technical Univ. Munich (Germany). Dept. for Diagnostic and Interventional Radiology and Nuclear Medicine; Reiser, M.F. (eds.) [University Hospitals - Grosshadern and Innenstadt Munich Univ. (Germany). Dept. of Clinical Radiology

    2008-07-01

    Thermal ablation has become an integral part of oncology, especially in the field of interventional oncology. This very comprehensive book encompasses the different technologies employed in thermal ablation, its indications and the results achieved in various clinical conditions. The first part of the book clearly explains the basics of thermal ablative techniques such as laser-induced thermotherapy, radiofrequency ablation, microwave ablation, cryotherapy, and localized tumor therapy. The latest developments in the application of minimally invasive therapies in localized neoplastic disease are demonstrated. In the main part of the book, techniques of guiding the applicators to the target structures by use of different imaging tools such as ultrasound, computed tomography and magnetic resonance imaging are discussed. The results are presented for a variety of clinical indications, including liver and lung tumors and metastases and some rather rare conditions involving the kidney, the head and neck, the prostate, and soft tissue structures. A large number of acknowledged experts have contributed to the book, which benefits from a lucid structure and excellent images. (orig.)

  17. Percutaneous tumor ablation in medical radiology

    International Nuclear Information System (INIS)

    Vogl, T.J.; Mack, M.G.; Helmberger, T.K.; Reiser, M.F.

    2008-01-01

    Thermal ablation has become an integral part of oncology, especially in the field of interventional oncology. This very comprehensive book encompasses the different technologies employed in thermal ablation, its indications and the results achieved in various clinical conditions. The first part of the book clearly explains the basics of thermal ablative techniques such as laser-induced thermotherapy, radiofrequency ablation, microwave ablation, cryotherapy, and localized tumor therapy. The latest developments in the application of minimally invasive therapies in localized neoplastic disease are demonstrated. In the main part of the book, techniques of guiding the applicators to the target structures by use of different imaging tools such as ultrasound, computed tomography and magnetic resonance imaging are discussed. The results are presented for a variety of clinical indications, including liver and lung tumors and metastases and some rather rare conditions involving the kidney, the head and neck, the prostate, and soft tissue structures. A large number of acknowledged experts have contributed to the book, which benefits from a lucid structure and excellent images. (orig.)

  18. Computer modeling of the combined effects of perfusion, electrical conductivity, and thermal conductivity on tissue heating patterns in radiofrequency tumor ablation.

    Science.gov (United States)

    Ahmed, Muneeb; Liu, Zhengjun; Humphries, Stanley; Goldberg, S Nahum

    2008-11-01

    To use an established computer simulation model of radiofrequency (RF) ablation to characterize the combined effects of varying perfusion, and electrical and thermal conductivity on RF heating. Two-compartment computer simulation of RF heating using 2-D and 3-D finite element analysis (ETherm) was performed in three phases (n = 88 matrices, 144 data points each). In each phase, RF application was systematically modeled on a clinically relevant template of application parameters (i.e., varying tumor and surrounding tissue perfusion: 0-5 kg/m(3)-s) for internally cooled 3 cm single and 2.5 cm cluster electrodes for tumor diameters ranging from 2-5 cm, and RF application times (6-20 min). In the first phase, outer thermal conductivity was changed to reflect three common clinical scenarios: soft tissue, fat, and ascites (0.5, 0.23, and 0.7 W/m- degrees C, respectively). In the second phase, electrical conductivity was changed to reflect different tumor electrical conductivities (0.5 and 4.0 S/m, representing soft tissue and adjuvant saline injection, respectively) and background electrical conductivity representing soft tissue, lung, and kidney (0.5, 0.1, and 3.3 S/m, respectively). In the third phase, the best and worst combinations of electrical and thermal conductivity characteristics were modeled in combination. Tissue heating patterns and the time required to heat the entire tumor +/-a 5 mm margin to >50 degrees C were assessed. Increasing background tissue thermal conductivity increases the time required to achieve a 50 degrees C isotherm for all tumor sizes and electrode types, but enabled ablation of a given tumor size at higher tissue perfusions. An inner thermal conductivity equivalent to soft tissue (0.5 W/m- degrees C) surrounded by fat (0.23 W/m- degrees C) permitted the greatest degree of tumor heating in the shortest time, while soft tissue surrounded by ascites (0.7 W/m- degrees C) took longer to achieve the 50 degrees C isotherm, and complete ablation

  19. Chemothermal Therapy for Localized Heating and Ablation of Tumor

    Directory of Open Access Journals (Sweden)

    Zhong-Shan Deng

    2013-01-01

    Full Text Available Chemothermal therapy is a new hyperthermia treatment on tumor using heat released from exothermic chemical reaction between the injected reactants and the diseased tissues. With the highly minimally invasive feature and localized heating performance, this method is expected to overcome the ubiquitous shortcomings encountered by many existing hyperthermia approaches in ablating irregular tumor. This review provides a relatively comprehensive review on the latest advancements and state of the art in chemothermal therapy. The basic principles and features of two typical chemothermal ablation strategies (acid-base neutralization-reaction-enabled thermal ablation and alkali-metal-enabled thermal/chemical ablation are illustrated. The prospects and possible challenges facing chemothermal ablation are analyzed. The chemothermal therapy is expected to open many clinical possibilities for precise tumor treatment in a minimally invasive way.

  20. Percutaneous thermal ablation of renal neoplasms; Perkutane Thermoablation von Nierentumoren

    Energy Technology Data Exchange (ETDEWEB)

    Tacke, J. [Inst. fuer Diagnostische und Interventionelle Radiologie/Neuroradiologie, Klinikum Passau (Germany); Mahnken, A.H.; Guenther, R.W. [Klinik fuer Radiologische Diagnostik, Universitaetsklinikum Aachen (Germany)

    2005-12-15

    Due to modern examination techniques such as multidetector computed tomography and high-field magnetic resonance imaging, the detection rate of renal neoplasms is continually increasing. Even though tumors exceeding 4 cm in diameter rarely metastasize, all renal lesions that are possible neoplasms should be treated. Traditional treatment techniques include radical nephrectomy or nephron-sparing resection, which are increasingly performed laparoscopically. Modern thermal ablation techniques such as hyperthermal techniques like radiofrequency ablation RFA, laser induced thermal ablation LITT, focused ultrasound FUS and microwave therapy MW, as well as hypothermal techniques (cryotherapy) may be a useful treatment option for patients who are unfit for or refuse surgical resection. Cryotherapy is the oldest and best known thermal ablation technique and can be performed laparoscopically or percutaneously. Since subzero temperatures have no antistyptic effect, additional maneuvers must be performed to control bleeding. Percutaneous cryotherapy of renal tumors is a new and interesting method, but experience with it is still limited. Radiofrequency ablation is the most frequently used method. Modern probe design allows volumes between 2 and 5 cm in diameter to be ablated. Due to hyperthermal tract ablation, the procedure is deemed to be safe and has a low complication rate. Although there are no randomized comparative studies to open resection, the preliminary results for renal RFA are promising and show RFA to be superior to other thermal ablation techniques. Clinical success rates are over 90% for both, cryo- and radiofrequency ablation. Whereas laser induced thermal therapy is established in hepatic ablation, experience is minimal with respect to renal application. For lesions of more than 2 cm in diameter, additional cooling catheters are required. MR thermometry offers temperature control during ablation. Microwave ablation is characterized by small ablation volumes

  1. Radiofrequency ablation of liver tumors (II): clinical application and outcomes.

    Science.gov (United States)

    Vanagas, Tomas; Gulbinas, Antanas; Pundzius, Juozas; Barauskas, Giedrius

    2010-01-01

    Radiofrequency ablation is one of the alternatives in the management of liver tumors, especially in patients who are not candidates for surgery. The aim of this article is to review applicability of radiofrequency ablation achieving complete tumor destruction, utility of imaging techniques for patients' follow-up, indications for local ablative procedures, procedure-associated morbidity and mortality, and long-term results in patients with different tumors. The success of local thermal ablation consists in creating adequate volumes of tissue destruction with adequate "clear margin," depending on improved delivery of radiofrequency energy and modulated tissue biophysiology. Different volumes of coagulation necrosis are achieved applying different types of electrodes, pulsing energy sources, utilizing sophisticated ablation schemes. Some additional methods are used to increase the overall deposition of energy through alterations in tissue electrical conductivity, to improve heat retention within the tissue, and to modulate tolerance of tumor tissue to hyperthermia. Contrast-enhanced computed tomography, magnetic resonance imaging, ultrasound or positron emission tomography are applied to control the effectiveness of radiofrequency ablation. The long-term results of radiofrequency ablation are controversial.

  2. Numerical Study for Optimizing Parameters of High-Intensity Focused Ultrasound-Induced Thermal Field during Liver Tumor Ablation: HIFU Simulator

    Directory of Open Access Journals (Sweden)

    Somayeh gharloghi

    2017-03-01

    Full Text Available Introduction High intensity focused ultrasound (HIFU is considered a noninvasive and effective technique for tumor ablation. Frequency and acoustic power are the most effective parameters for temperature distribution and the extent of tissue damage. The aim of this study was to optimize the operating transducer parameters such as frequency and input power in order to acquire suitable temperature and thermal dose distribution in the course of a numerical assessment. Materials and Methods To model the sound propagation, the Khokhlov-Zabolotskava-Kuznetsov (KZK nonlinear wave equation was used and simulation was carried out using MATLAB HIFU toolbox. Bioheat equation was applied to calculate the transient temperature in the liver tissue. Frequency ranges of 2, 3, 4, and 5 MHz and power levels of 50 and 100 W were applied using an extracorporeal transducer. Results Using a frequency of 2 MHz, the maximum temperatures reached 53°C and 90°C in the focal point for power levels of 50 W and 100 W, respectively. With the same powers and using a frequency of 3 MHz, the temperature reached to 71°C and 170°C, respectively. In addition, for these power levels at the frequency of 4 MHz, the temperature reached to 72°C and 145°C, respectively. However, at the 5 MHz frequency, the temperature in the focal spot was either 57°C or 79°C. Conclusion Use of frequency of 2 MHz and power of 100 W led to higher thermal dose distribution, and subsequently, reduction of the treatment duration and complications at the same exposure time in ablation of large tumors.

  3. Research of electrosurgical unit with novel antiadhesion composite thin film for tumor ablation: Microstructural characteristics, thermal conduction properties, and biological behaviors.

    Science.gov (United States)

    Shen, Yun-Dun; Lin, Li-Hsiang; Chiang, Hsi-Jen; Ou, Keng-Liang; Cheng, Han-Yi

    2016-01-01

    The objective of this study was to use surface functionalization to evaluate the antiadhesion property and thermal injury effects on the liver when using a novel electrosurgical unit with nanostructured-doped diamond-like carbon (DLC-Cu) thin films for tumor ablations. The physical and chemical properties of DLC-Cu thin films were characterized by contact angle goniometer, scanning electron microscope, and transmission electron microscope. Three-dimensional (3D) hepatic models were reconstructed using magnetic resonance imaging to simulate a clinical electrosurgical operation. The results indicated a significant increase of the contact angle on the nanostructured DLC-Cu thin films, and the antiadhesion properties were also observed in an animal model. Furthermore, the surgical temperature in the DLC-Cu electrosurgical unit was found to be significantly lower than the untreated unit when analyzed using 3D models and thermal images. In addition, DLC-Cu electrodes caused a relatively small injury area and lateral thermal effect. The results indicated that the nanostructured DLC-Cu thin film coating reduced excessive thermal injury and tissue adherence effect in the liver. © 2015 Wiley Periodicals, Inc.

  4. Radiofrequency Ablation of Liver Tumors

    Science.gov (United States)

    ... have had a surgical procedure in which the liver bile duct has been connected to a loop of bowel are at much greater risk of developing a liver abscess after ablation. Women should always inform their ...

  5. Microwave ablation of renal tumors: state of the art and development trends.

    Science.gov (United States)

    Floridi, Chiara; De Bernardi, Irene; Fontana, Federico; Muollo, Alessandra; Ierardi, Anna Maria; Agostini, Andrea; Fonio, Paolo; Squillaci, Ettore; Brunese, Luca; Fugazzola, Carlo; Carrafiello, Gianpaolo

    2014-07-01

    In the last decades an increased incidence of new renal tumor cases has been for clinically localized, small tumors elderly patients, with medical comorbidities whom the risk of surgical complications may pose a greater risk of death than that due to the tumor itself. In these patients, unsuitable for surgical approach, thermal ablation represents a valid alternative to traditional surgery. Thermal ablation is a less invasive, less morbid treatment option thanks to reduced blood loss, lower incidence of complications during the procedure and a less long convalescence. At present, the most widely used thermal ablative techniques are cryoablation, radiofrequency ablation and microwave ablation (MWA). MWA offers many benefits of other ablation techniques and offers several other advantages: higher intratumoral temperatures, larger tumor ablation volumes, faster ablation times, the ability to use multiple applicators simultaneously, optimal heating of cystic masses and tumors close to the vessels and less procedural pain. This review aims to provide the reader with an overview about the state of the art of microwave ablation for renal tumors and to cast a glance on the new development trends of this technique.

  6. Endoluminal ultrasound applicators for MR-guided thermal ablation of pancreatic tumors: Preliminary design and evaluation in a porcine pancreas model

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Matthew S., E-mail: matt.adams@ucsf.edu; Diederich, Chris J. [Thermal Therapy Research Group, University of California, San Francisco, 2340 Sutter Street, S341, San Francisco, California 94115 and The UC Berkeley - UCSF Graduate Program in Bioengineering, University of California, Berkeley, and University of California, San Francisco, California 94115 (United States); Salgaonkar, Vasant A.; Jones, Peter D. [Thermal Therapy Research Group, University of California, San Francisco, 2340 Sutter Street, S341, San Francisco, California 94115 (United States); Plata-Camargo, Juan; Sommer, Graham; Pauly, Kim Butts [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Pascal-Tenorio, Aurea; Bouley, Donna M. [Department of Comparative Medicine, Stanford University, Stanford, California 94305 (United States); Chen, Hsin-Yu [The UC Berkeley - UCSF Graduate Program in Bioengineering, University of California, Berkeley, and University of California, San Francisco, California 94115 (United States)

    2016-07-15

    Purpose: Endoluminal ultrasound may serve as a minimally invasive option for delivering thermal ablation to pancreatic tumors adjacent to the stomach or duodenum. The objective of this study was to explore the basic feasibility of this treatment strategy through the design, characterization, and evaluation of proof-of-concept endoluminal ultrasound applicators capable of placement in the gastrointestinal (GI) lumen for volumetric pancreas ablation under MR guidance. Methods: Two variants of the endoluminal applicator, each containing a distinct array of two independently powered transducers (10 × 10 mm 3.2 MHz planar; or 8 × 10 × 20 mm radius of curvature 3.3 MHz curvilinear geometries) at the distal end of a meter long flexible catheter assembly, were designed and fabricated. Transducers and circulatory water flow for acoustic coupling and luminal cooling were contained by a low-profile polyester balloon covering the transducer assembly fixture. Each applicator incorporated miniature spiral MR coils and mechanical features (guiding tips and hinges) to facilitate tracking and insertion through the GI tract under MRI guidance. Acoustic characterization of each device was performed using radiation force balance and hydrophone measurements. Device delivery into the upper GI tract, adjacent to the pancreas, and heating characteristics for treatment of pancreatic tissue were evaluated in MR-guided ex vivo and in vivo porcine experiments. MR guidance was utilized for anatomical target identification, tracking/positioning of the applicator, and MR temperature imaging (MRTI) for PRF-based multislice thermometry, implemented in the real-time RTHawk software environment. Results: Force balance and hydrophone measurements indicated efficiencies of 48.8% and 47.8% and −3 dB intensity beam-widths of 3.2 and 1.2 mm for the planar and curvilinear transducers, respectively. Ex vivo studies on whole-porcine carcasses revealed capabilities of producing ablative temperature rise

  7. Endoluminal ultrasound applicators for MR-guided thermal ablation of pancreatic tumors: Preliminary design and evaluation in a porcine pancreas model

    International Nuclear Information System (INIS)

    Adams, Matthew S.; Diederich, Chris J.; Salgaonkar, Vasant A.; Jones, Peter D.; Plata-Camargo, Juan; Sommer, Graham; Pauly, Kim Butts; Pascal-Tenorio, Aurea; Bouley, Donna M.; Chen, Hsin-Yu

    2016-01-01

    Purpose: Endoluminal ultrasound may serve as a minimally invasive option for delivering thermal ablation to pancreatic tumors adjacent to the stomach or duodenum. The objective of this study was to explore the basic feasibility of this treatment strategy through the design, characterization, and evaluation of proof-of-concept endoluminal ultrasound applicators capable of placement in the gastrointestinal (GI) lumen for volumetric pancreas ablation under MR guidance. Methods: Two variants of the endoluminal applicator, each containing a distinct array of two independently powered transducers (10 × 10 mm 3.2 MHz planar; or 8 × 10 × 20 mm radius of curvature 3.3 MHz curvilinear geometries) at the distal end of a meter long flexible catheter assembly, were designed and fabricated. Transducers and circulatory water flow for acoustic coupling and luminal cooling were contained by a low-profile polyester balloon covering the transducer assembly fixture. Each applicator incorporated miniature spiral MR coils and mechanical features (guiding tips and hinges) to facilitate tracking and insertion through the GI tract under MRI guidance. Acoustic characterization of each device was performed using radiation force balance and hydrophone measurements. Device delivery into the upper GI tract, adjacent to the pancreas, and heating characteristics for treatment of pancreatic tissue were evaluated in MR-guided ex vivo and in vivo porcine experiments. MR guidance was utilized for anatomical target identification, tracking/positioning of the applicator, and MR temperature imaging (MRTI) for PRF-based multislice thermometry, implemented in the real-time RTHawk software environment. Results: Force balance and hydrophone measurements indicated efficiencies of 48.8% and 47.8% and −3 dB intensity beam-widths of 3.2 and 1.2 mm for the planar and curvilinear transducers, respectively. Ex vivo studies on whole-porcine carcasses revealed capabilities of producing ablative temperature rise

  8. Real-time monitoring of radiofrequency ablation of liver tumors using thermal-dose calculation by MR temperature imaging: initial results in nine patients, including follow-up

    International Nuclear Information System (INIS)

    Lepetit-Coiffe, Matthieu; Quesson, Bruno; Moonen, Chrit T.W.; Laumonier, Herve; Trillaud, Herve; Seror, Olivier; Sesay, Musa-Bahazid; Grenier, Nicolas

    2010-01-01

    To assess the practical feasibility and effectiveness of real-time magnetic resonance (MR) temperature monitoring for the radiofrequency (RF) ablation of liver tumours in a clinical setting, nine patients (aged 49-87 years, five men and four women) with one malignant tumour (14-50 mm, eight hepatocellular carcinomas and one colorectal metastasis), were treated by 12-min RF ablation using a 1.5-T closed magnet for real-time temperature monitoring. The clinical monopolar RF device was filtered at 64 MHz to avoid electromagnetic interference. Real-time computation of thermal-dose (TD) maps, based on Sapareto and Dewey's equation, was studied to determine its ability to provide a clear end-point of the RF procedure. Absence of local recurrence on follow-up MR images obtained 45 days after the RF ablation was used to assess the apoptotic and necrotic prediction obtained by real-time TD maps. Seven out of nine tumours were completely ablated according to the real-time TD maps. Compared with 45-day follow-up MR images, TD maps accurately predicted two primary treatment failures, but were not relevant in the later progression of one case of secondary local tumour. The real-time TD concept is a feasible and promising monitoring method for the RF ablation of liver tumours. (orig.)

  9. Real-time monitoring of radiofrequency ablation of liver tumors using thermal-dose calculation by MR temperature imaging: initial results in nine patients, including follow-up

    Energy Technology Data Exchange (ETDEWEB)

    Lepetit-Coiffe, Matthieu; Quesson, Bruno; Moonen, Chrit T.W. [Universite Victor Segalen Bordeaux 2, Laboratoire Imagerie Moleculaire et Fonctionnelle: de la physiologie a la therapie CNRS UMR 5231, Bordeaux Cedex (France); Laumonier, Herve; Trillaud, Herve [Universite Victor Segalen Bordeaux 2, Laboratoire Imagerie Moleculaire et Fonctionnelle: de la physiologie a la therapie CNRS UMR 5231, Bordeaux Cedex (France); Service de Radiologie, Hopital Saint-Andre, CHU Bordeaux, Bordeaux (France); Seror, Olivier [Universite Victor Segalen Bordeaux 2, Laboratoire Imagerie Moleculaire et Fonctionnelle: de la physiologie a la therapie CNRS UMR 5231, Bordeaux Cedex (France); Service de Radiologie, Hopital Jean Verdier, Bondy (France); Sesay, Musa-Bahazid [Service d' Anesthesie Reanimation III, Hopital Pellegrin, CHU Bordeaux, Bordeaux (France); Grenier, Nicolas [Universite Victor Segalen Bordeaux 2, Laboratoire Imagerie Moleculaire et Fonctionnelle: de la physiologie a la therapie CNRS UMR 5231, Bordeaux Cedex (France); Service d' Imagerie Diagnostique et Therapeutique de l' Adulte, Hopital Pellegrin, CHU Bordeaux, Bordeaux (France)

    2010-01-15

    To assess the practical feasibility and effectiveness of real-time magnetic resonance (MR) temperature monitoring for the radiofrequency (RF) ablation of liver tumours in a clinical setting, nine patients (aged 49-87 years, five men and four women) with one malignant tumour (14-50 mm, eight hepatocellular carcinomas and one colorectal metastasis), were treated by 12-min RF ablation using a 1.5-T closed magnet for real-time temperature monitoring. The clinical monopolar RF device was filtered at 64 MHz to avoid electromagnetic interference. Real-time computation of thermal-dose (TD) maps, based on Sapareto and Dewey's equation, was studied to determine its ability to provide a clear end-point of the RF procedure. Absence of local recurrence on follow-up MR images obtained 45 days after the RF ablation was used to assess the apoptotic and necrotic prediction obtained by real-time TD maps. Seven out of nine tumours were completely ablated according to the real-time TD maps. Compared with 45-day follow-up MR images, TD maps accurately predicted two primary treatment failures, but were not relevant in the later progression of one case of secondary local tumour. The real-time TD concept is a feasible and promising monitoring method for the RF ablation of liver tumours. (orig.)

  10. Radiofrequency ablation for renal tumors. Our experience

    International Nuclear Information System (INIS)

    Hiraoka, Kenji; Kawauchi, Akihiro; Nakamura, Terukazu; Soh, Jintetsu; Mikami, Kazuya; Miki, Tsuneharu

    2009-01-01

    The objective of this study was to report our results of percutaneous radiofrequency ablation (RFA) for renal tumors and to assess predictors of therapeutic efficacy. Forty patients (median age 73 years) with renal tumors were treated with RFA under local or epidural anesthesia. All of them had high surgical risk or refused radical surgery. Tumors were punctured percutaneously using the Radionics Cool-tip RF System under computed tomography or ultrasonographic guidance. Median tumor diameter was 24 mm. After RFA, contrast-enhanced computed tomography or magnetic resonance imaging was performed within 1 month. Complete response (CR) was defined as no enhancement inside the tumor. Factors related to the outcome and to renal function were assessed. Median follow up was 16 months. CR was observed in 34 cases (85.0%). A significant difference in CR rate was observed between tumors ≤30 mm and those >30 mm. Outcomes tended to be better for tumors in the mid to lower kidney, and those away from the renal hilum. Recurrence was observed in one case (2.9%), but a CR was obtained again by additional RFA. Out of a total of 77 RFA procedures, complications occurred in only three cases (3.9%), and conservative treatment was possible in all cases. Serum creatinine levels 3 months after RFA did not differ from those before RFA. Percutaneous RFA is a safe and effective treatment for small renal tumors in patients with high surgical risk or who refuse radical surgery. (author)

  11. Radio frequency ablation of small renal tumors:: intermediate results.

    Science.gov (United States)

    Hwang, J J; Walther, M M; Pautler, S E; Coleman, J A; Hvizda, J; Peterson, James; Linehan, W M; Wood, B J

    2004-05-01

    With evolving radio frequency technology, the clinical application of radio frequency ablation (RFA) has been actively investigated in the treatment for small renal tumors. We present our intermediate patient outcomes after RFA. Since January 2001, 17 patients with a total of 24 hereditary renal tumors ranging from 1.2 to 2.85 cm were treated with RFA using the 200 W Cool-tip RF System (Radionics, Burlington, Massachusetts) under laparoscopic (9) or percutaneous (8) guidance and had a minimum 1-year followup. A percutaneous approach was considered unsuitable if kidney tumors were contiguous to bowel, ureter or large vessels. Treatment eligibility criteria included an average tumor diameter of less than 3.0 cm, tumor growth during 1 year and solid appearance with contrast enhancement (HU change greater than 20) on computerized tomography (CT). Postoperative followup consisted of CT with and without intravenous contrast, and renal function assessment at regular intervals. Median patient age was 38 years (range 20 to 51). At a median followup of 385 days (range 342 to 691), median tumor or thermal lesion diameter decreased from 2.26 to 1.62 cm (p = 0.0013), and only 1 lesion (4%), which was located centrally near the hilum, exhibited contrast enhancement (HU change greater than 10) on CT at 12 months. Of the 15 renal tumors ablated laparoscopically, 13 were in direct contact with the bowel and 2 were abutting the ureter, necessitating mobilization before RFA. Laparoscopic ultrasound was used to guide radio frequency electrode placement and monitor the ablation process in these cases. Operative time and intraoperative blood loss (mean +/- standard mean of error) were 243 +/- 29 minutes and 67 +/- 9 cc, respectively. In 1 patient whose ureter was adherent to the tumor a ureteropelvic junction obstruction developed after laparoscopic RFA, requiring open repair. At the minimum 1-year followup 23 of 24 ablated tumors lacked contrast uptake on CT, meeting our radiographic

  12. Factors Limiting Complete Tumor Ablation by Radiofrequency Ablation

    International Nuclear Information System (INIS)

    Paulet, Erwan; Aube, Christophe; Pessaux, Patrick; Lebigot, Jerome; Lhermitte, Emilie; Oberti, Frederic; Ponthieux, Anne; Cales, Paul; Ridereau-Zins, Catherine; Pereira, Philippe L.

    2008-01-01

    The purpose of this study was to determine radiological or physical factors to predict the risk of residual mass or local recurrence of primary and secondary hepatic tumors treated by radiofrequency ablation (RFA). Eighty-two patients, with 146 lesions (80 hepatocellular carcinomas, 66 metastases), were treated by RFA. Morphological parameters of the lesions included size, location, number, ultrasound echogenicity, computed tomography density, and magnetic resonance signal intensity were obtained before and after treatment. Parameters of the generator were recorded during radiofrequency application. The recurrence-free group was statistically compared to the recurrence and residual mass groups on all these parameters. Twenty residual masses were detected. Twenty-nine lesions recurred after a mean follow-up of 18 months. Size was a predictive parameter. Patients' sex and age and the echogenicity and density of lesions were significantly different for the recurrence and residual mass groups compared to the recurrence-free group (p < 0.05). The presence of an enhanced ring on the magnetic resonance control was more frequent in the recurrence and residual mass groups. In the group of patients with residual lesions, analysis of physical parameters showed a significant increase (p < 0.05) in the time necessary for the temperature to rise. In conclusion, this study confirms risk factors of recurrence such as the size of the tumor and emphasizes other factors such as a posttreatment enhanced ring and an increase in the time necessary for the rise in temperature. These factors should be taken into consideration when performing RFA and during follow-up

  13. Careful treatment planning enables safe ablation of liver tumors adjacent to major blood vessels by percutaneous irreversible electroporation (IRE

    Directory of Open Access Journals (Sweden)

    Kos Bor

    2015-09-01

    Full Text Available Background. Irreversible electroporation (IRE is a tissue ablation method, which relies on the phenomenon of electroporation. When cells are exposed to a sufficiently electric field, the plasma membrane is disrupted and cells undergo an apoptotic or necrotic cell death. Although heating effects are known IRE is considered as non-thermal ablation technique and is currently applied to treat tumors in locations where thermal ablation techniques are contraindicated.

  14. Endometrial ablation by rollerball electrocoagulation compared to uterine balloon thermal ablation. Technical and safety aspects.

    NARCIS (Netherlands)

    Zon-Rabelink, I.A.A. van; Vleugels, M.P.; Merkus, J.M.W.M.; Graaf, R.M. de

    2003-01-01

    OBJECTIVE: To compare two methods of endometrial ablation, hysteroscopic rollerball electrocoagulation (RBE) and non-hysteroscopic uterine balloon thermal (UBT) ablation (Thermachoice), regarding intra- and post-operative technical complications and safety aspects. STUDY DESIGN: A randomised

  15. MR thermometry for monitoring tumor ablation

    International Nuclear Information System (INIS)

    Senneville, Baudouin D. de; Quesson, Bruno; Dragonu, Iulius; Moonen, Chrit T.W.; Mougenot, Charles; Grenier, Nicolas

    2007-01-01

    Local thermal therapies are increasingly used in the clinic for tissue ablation. During energy deposition, the actual tissue temperature is difficult to estimate since physiological processes may modify local heat conduction and energy absorption. Blood flow may increase during temperature increase and thus change heat conduction. In order to improve the therapeutic efficiency and the safety of the intervention, mapping of temperature and thermal dose appear to offer the best strategy to optimize such interventions and to provide therapy endpoints. MRI can be used to monitor local temperature changes during thermal therapies. On-line availability of dynamic temperature mapping allows prediction of tissue death during the intervention based on semi-empirical thermal dose calculations. Much progress has been made recently in MR thermometry research, and some applications are appearing in the clinic. In this paper, the principles of MRI temperature mapping are described with special emphasis on methods employing the temperature dependency of the water proton resonance frequency. Then, the prospects and requirements for widespread applications of MR thermometry in the clinic are evaluated. (orig.)

  16. Thermochemical ablation therapy of VX2 tumor using a permeable oil-packed liquid alkali metal.

    Directory of Open Access Journals (Sweden)

    Ziyi Guo

    Full Text Available Alkali metal appears to be a promising tool in thermochemical ablation, but, it requires additional data on safety is required. The objective of this study was to explore the effectiveness of permeable oil-packed liquid alkali metal in the thermochemical ablation of tumors.Permeable oil-packed sodium-potassium (NaK was prepared using ultrasonic mixing of different ratios of metal to oil. The thermal effect of the mixture during ablation of muscle tissue ex vivo was evaluated using the Fluke Ti400 Thermal Imager. The thermochemical effect of the NaK-oil mixture on VX2 tumors was evaluated by performing perfusion CT scans both before and after treatment in 10 VX2 rabbit model tumors. VX2 tumors were harvested from two rabbits immediately after treatment to assess their viability using trypan blue and hematoxylin and eosin (H.E. staining.The injection of the NaK-oil mixture resulted in significantly higher heat in the ablation areas. The permeable oil controlled the rate of heat released during the NaK reaction with water in the living tissue. Perfusion computed tomography and its parameter map confirmed that the NaK-oil mixture had curative effects on VX2 tumors. Both trypan blue and H.E. staining showed partial necrosis of the VX2 tumors.The NaK-oil mixture may be used successfully to ablate tumor tissue in vivo. With reference to the controlled thermal and chemical lethal injury to tumors, using a liquid alkali in ablation is potentially an effective and safe method to treat malignant tumors.

  17. Ultrasound-guided percutaneous radiofrequency ablation of liver tumors: How we do it safety and completely

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Woong; Shin, Sang Soo; Heo, Suk Hee; Hong, Jun Hyung; Lim, Hyo Soon; Seon, Hyun Ju; Hur, Young Hoe; Park, Chang Hwan; Jeong, Yong Yeon; Kang, Heoung Keun [Chonnam National University Medical School, Gwangju (Korea, Republic of)

    2015-12-15

    Ultrasound-guided percutaneous radiofrequency (RF) ablation has become one of the most promising local cancer therapies for both resectable and nonresectable hepatic tumors. Although RF ablation is a safe and effective technique for the treatment of liver tumors, the outcome of treatment can be closely related to the location and shape of the tumors. There may be difficulties with RF ablation of tumors that are adjacent to large vessels or extrahepatic heat-vulnerable organs and tumors in the caudate lobe, possibly resulting in major complications or treatment failure. Thus, a number of strategies have been developed to overcome these challenges, which include artificial ascites, needle track ablation, fusion imaging guidance, parallel targeting, bypass targeting, etc. Operators need to use the right strategy in the right situation to avoid the possibility of complications and incomplete thermal tissue destruction; with the right strategy, RF ablation can be performed successfully, even for hepatic tumors in high-risk locations. This article offers technical strategies that can be used to effectively perform RF ablation as well as to minimize possible complications related to the procedure with representative cases and schematic illustrations.

  18. Laser ablation of tumors: current concepts and recent developments

    International Nuclear Information System (INIS)

    Stroszczynski, C.; Gaffke, G.; Gnauck, M.; Ricke, J.; Felix, R.; Puls, R.; Speck, U.; Hosten, N.; Oettle, H.; Hohenberger, P.

    2004-01-01

    Purpose. The purpose of this paper is to present technical innovations and clinical results of percutaneous interventional laser ablation of tumors using new techniques. Methods. Laser ablation was performed in 182 patients (liver tumors: 131, non hepatic tumors - bone, lung, others: 51) after interdisciplinary consensus was obtained. The procedure was done using a combination of imaging modalities (CT/MRI, CT/US) or only closed high field MRI (1.5 T). All patients received an MRI-scan immediately after laser ablation. Results. In 90.9% of the patients with liver tumors, a complete ablation was achieved. Major events occurred in 5.4%. The technical success rate of laser ablation in non-hepatic tumors was high, clinical results differed depending on the treated organ. Conclusions. The treatment of tumors of the liver and other organs up to 5 cm by laser ablation was a safe procedure with a low rate of complications and side effects. Image guidance by MRI is advantageous for precise tumor visualization in all dimensions, therapy monitoring, and control of laser ablation results. (orig.) [de

  19. Tumor Seeding Following Lung Radiofrequency Ablation: A Case Report

    International Nuclear Information System (INIS)

    Yamakado, Koichiro; Akeboshi, Masao; Nakatsuka, Atsuhiro; Takaki, Haruyuki; Takao, Motoshi; Kobayashi, Hiroyasu; Taguchi, Osamu; Takeda, Kan

    2005-01-01

    Lung radiofrequency (RF) ablation was performed for the treatment of a primary lung cancer measuring 2.5 cm in maximum diameter in a 78-year-old man. A contrast-enhanced computed tomography (CT) study performed 3 months after RF ablation showed incomplete ablation of the lung tumor and the appearance of a chest wall tumor 4.0 cm in maximum diameter that was considered to be the result of needle-tract seeding. RF ablation was performed for the treatment of both the lung and the chest wall tumors. Although tumor enhancement was eradicated in both of the treated tumors, follow-up CT studies revealed diffuse intra-pulmonary metastases in both lungs 2 months after the second RF session. He is currently receiving systemic chemotherapy

  20. Thermal Ablation of T1c Renal Cell Carcinoma: A Comparative Assessment of Technical Performance, Procedural Outcome, and Safety of Microwave Ablation, Radiofrequency Ablation, and Cryoablation.

    Science.gov (United States)

    Zhou, Wenhui; Arellano, Ronald S

    2018-04-06

    To evaluate perioperative outcomes of thermal ablation with microwave (MW), radiofrequency (RF), and cryoablation for stage T1c renal cell carcinoma (RCC). A retrospective analysis of 384 patients (mean age, 71 y; range, 22-88 y) was performed between October 2006 and October 2016. Mean radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior, and location relative to polar lines; preoperative aspects and dimensions used for anatomic classification; and centrality index scores were 6.3, 7.9, and 2.7, respectively. Assessment of pre- and postablation serum blood urea nitrogen, creatinine, and estimated glomerular filtration rate was performed to assess functional outcomes. Linear regression analyses were performed to compare sedation medication dosages among the three treatment cohorts. Univariable and multivariable logistic regression analyses were performed to compare rates of residual disease and complications among treatment modalities. A total of 437 clinical stage T1N0M0 biopsy-proven RCCs measuring 1.2-6.9 cm were treated with computed tomography (CT)-guided MW ablation (n = 44; 10%), RF ablation (n = 347; 79%), or cryoablation (n = 46; 11%). There were no significant differences in patient demographic or tumor characteristics among cohorts. Complication rates and immediate renal function changes were similar among the three ablation modalities (P = .46 and P = .08, respectively). MW ablation was associated with significantly decreased ablation time (P < .05), procedural time (P < .05), and dosage of sedative medication (P < .05) compared with RF ablation and cryoablation. CT-guided percutaneous MW ablation is comparable to RF ablation or cryoablation for the treatment of stage T1N0M0 RCC with regard to treatment response and is associated with shorter treatment times and less sedation than RF ablation or cryoablation. In addition, the safety profile of CT-guided MW ablation is noninferior to those of RF ablation or

  1. CT-guided radiofrequency tumor ablation in children

    International Nuclear Information System (INIS)

    Botsa, Evanthia; Poulou, Loukia S.; Koundouraki, Antonia; Thanos, Loukas; Koutsogiannis, Ioannis; Ziakas, Panayiotis D.; Alexopoulou, Efthimia

    2014-01-01

    Image-guided radiofrequency ablation is a well-accepted technique of interventional oncology in adults. To evaluate the efficacy and safety of CT-guided radiofrequency ablation as a minimally invasive treatment for metastatic neoplasms in children. A total of 15 radiofrequency ablation sessions were performed in 12 children and young adults (median age 9.5; range 5-18 years) with metastatic malignancies. Seven children and young adults had secondary hepatic lesions, three had pulmonary and two had bone lesions. Radiofrequency ablation was performed under conscious sedation. The median lesion size was 1.7 cm (range 1.3-2.8 cm). The median time for ablation was 8 min (range 7-10 min). Radiofrequency procedures were technically successful in all tumors. Postablation imaging immediately after, and 1 month and 3 months after radiofrequency ablation showed total necrosis in all patients. At 6-month follow-up, three patients (all with lesion size >2 cm) had local recurrence and underwent a second radiofrequency ablation session. At 2-year follow-up no patient had recurrence of the treated tumor. Post-ablation syndrome occurred in four children. No major complication occurred. CT-guided radiofrequency tumor ablation was safe and efficient for palliative treatment in our cohort of patients. (orig.)

  2. CT-guided radiofrequency tumor ablation in children

    Energy Technology Data Exchange (ETDEWEB)

    Botsa, Evanthia [National and Kapodistrian University of Athens, First Pediatric Clinic, Agia Sofia Children' s Hospital, Athens (Greece); Poulou, Loukia S.; Koundouraki, Antonia; Thanos, Loukas [Sotiria General Hospital for Chest Diseases, Department of Medical Imaging and Interventional Radiology, Athens (Greece); Koutsogiannis, Ioannis [General Military Hospital NIMTS, Department of Medical Imaging, Athens (Greece); Ziakas, Panayiotis D. [Warren Alpert Medical School of Brown University Rhode Island Hospital, Division of Infectious Diseases, Providence, RI (United States); Alexopoulou, Efthimia [Attikon University Hospital, Second Department of Radiology, Athens University School of Medicine, Athens (Greece)

    2014-11-15

    Image-guided radiofrequency ablation is a well-accepted technique of interventional oncology in adults. To evaluate the efficacy and safety of CT-guided radiofrequency ablation as a minimally invasive treatment for metastatic neoplasms in children. A total of 15 radiofrequency ablation sessions were performed in 12 children and young adults (median age 9.5; range 5-18 years) with metastatic malignancies. Seven children and young adults had secondary hepatic lesions, three had pulmonary and two had bone lesions. Radiofrequency ablation was performed under conscious sedation. The median lesion size was 1.7 cm (range 1.3-2.8 cm). The median time for ablation was 8 min (range 7-10 min). Radiofrequency procedures were technically successful in all tumors. Postablation imaging immediately after, and 1 month and 3 months after radiofrequency ablation showed total necrosis in all patients. At 6-month follow-up, three patients (all with lesion size >2 cm) had local recurrence and underwent a second radiofrequency ablation session. At 2-year follow-up no patient had recurrence of the treated tumor. Post-ablation syndrome occurred in four children. No major complication occurred. CT-guided radiofrequency tumor ablation was safe and efficient for palliative treatment in our cohort of patients. (orig.)

  3. 3D Multifunctional Ablative Thermal Protection System

    Science.gov (United States)

    Feldman, Jay; Venkatapathy, Ethiraj; Wilkinson, Curt; Mercer, Ken

    2015-01-01

    NASA is developing the Orion spacecraft to carry astronauts farther into the solar system than ever before, with human exploration of Mars as its ultimate goal. One of the technologies required to enable this advanced, Apollo-shaped capsule is a 3-dimensional quartz fiber composite for the vehicle's compression pad. During its mission, the compression pad serves first as a structural component and later as an ablative heat shield, partially consumed on Earth re-entry. This presentation will summarize the development of a new 3D quartz cyanate ester composite material, 3-Dimensional Multifunctional Ablative Thermal Protection System (3D-MAT), designed to meet the mission requirements for the Orion compression pad. Manufacturing development, aerothermal (arc-jet) testing, structural performance, and the overall status of material development for the 2018 EM-1 flight test will be discussed.

  4. Thermal Ablation for Benign Thyroid Nodules: Radiofrequency and Laser

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Jung Hwan; Lee, Jeong Hyun [University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Valcavi, Roberto [Endocrinology Division and Thyroid Disease Center, Arcispedale Santa Maria Nuova, Reggio Emilia (Italy); Pacella, Claudio M. [Diagnostic Imaging and Interventional Radiology Department, Ospedale Regina Apostolorum, Albano Laziale-Rome (IT); Rhim, Hyun Chul [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Na, Dong Kyu [Human Medical Imaging and Intervention Center, Seoul (Korea, Republic of)

    2011-10-15

    Although ethanol ablation has been successfully used to treat cystic thyroid nodules, this procedure is less effective when the thyroid nodules are solid. Radiofrequency (RF) ablation, a newer procedure used to treat malignant liver tumors, has been valuable in the treatment of benign thyroid nodules regardless of the extent of the solid component. This article reviews the basic physics, techniques, applications, results, and complications of thyroid RF ablation, in comparison to laser ablation.

  5. Magnetic resonance–guided interstitial high-intensity focused ultrasound for brain tumor ablation

    Science.gov (United States)

    MacDonell, Jacquelyn; Patel, Niravkumar; Rubino, Sebastian; Ghoshal, Goutam; Fischer, Gregory; Burdette, E. Clif; Hwang, Roy; Pilitsis, Julie G.

    2018-01-01

    Currently, treatment of brain tumors is limited to resection, chemotherapy, and radiotherapy. Thermal ablation has been recently explored. High-intensity focused ultrasound (HIFU) is being explored as an alternative. Specifically, the authors propose delivering HIFU internally to the tumor with an MRI-guided robotic assistant (MRgRA). The advantage of the authors’ interstitial device over external MRI-guided HIFU (MRgHIFU) is that it allows for conformal, precise ablation and concurrent tissue sampling. The authors describe their workflow for MRgRA HIFU delivery. PMID:29385926

  6. Thermal infrared images to quantify thermal ablation effects of acid and base on target tissues

    Science.gov (United States)

    Liu, Ran; Wang, Jia; Liu, Jing

    2015-07-01

    Hyperthermia (42-46°C), treatment of tumor tissue through elevated temperature, offers several advantages including high cost-effectiveness, highly targeted ablation and fewer side effects and hence higher safety level over traditional therapies such as chemotherapy and radiotherapy. Recently, hyperthermia using heat release through exothermic acid-base neutralization comes into view owing to its relatively safe products of salt and water and highly confined ablation. However, lack of quantitative understanding of the spatial and temporal temperature profiles that are produced by simultaneous diffusion of liquid chemical and its chemical reaction within tumor tissue impedes the application of this method. This article is dedicated to quantify thermal ablation effects of acid and base both individually and as in neutralization via infrared captured thermal images. A theoretical model is used to approximate specific heat absorption rate (SAR) based on experimental measurements that contrast two types of tissue, normal pork and pig liver. According to the computation, both pork and liver tissue has a higher ability in absorbing hydrochloric acid (HCl) than sodium hydroxide, hence suggesting that a reduced dosage for HCl is appropriate in a surgery. The heating effect depends heavily on the properties of tissue types and amount of chemical reagents administered. Given thermal parameters such as SAR for different tissues, a computational model can be made in predicting temperature transitions which will be helpful in planning and optimizing surgical hyperthermia procedures.

  7. Thermal infrared images to quantify thermal ablation effects of acid and base on target tissues

    Directory of Open Access Journals (Sweden)

    Ran Liu

    2015-07-01

    Full Text Available Hyperthermia (42-46°C, treatment of tumor tissue through elevated temperature, offers several advantages including high cost-effectiveness, highly targeted ablation and fewer side effects and hence higher safety level over traditional therapies such as chemotherapy and radiotherapy. Recently, hyperthermia using heat release through exothermic acid-base neutralization comes into view owing to its relatively safe products of salt and water and highly confined ablation. However, lack of quantitative understanding of the spatial and temporal temperature profiles that are produced by simultaneous diffusion of liquid chemical and its chemical reaction within tumor tissue impedes the application of this method. This article is dedicated to quantify thermal ablation effects of acid and base both individually and as in neutralization via infrared captured thermal images. A theoretical model is used to approximate specific heat absorption rate (SAR based on experimental measurements that contrast two types of tissue, normal pork and pig liver. According to the computation, both pork and liver tissue has a higher ability in absorbing hydrochloric acid (HCl than sodium hydroxide, hence suggesting that a reduced dosage for HCl is appropriate in a surgery. The heating effect depends heavily on the properties of tissue types and amount of chemical reagents administered. Given thermal parameters such as SAR for different tissues, a computational model can be made in predicting temperature transitions which will be helpful in planning and optimizing surgical hyperthermia procedures.

  8. Thermal infrared images to quantify thermal ablation effects of acid and base on target tissues

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ran, E-mail: jliubme@tsinghua.edu.cn, E-mail: liuran@tsinghua.edu.cn; Liu, Jing, E-mail: jliubme@tsinghua.edu.cn, E-mail: liuran@tsinghua.edu.cn [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China); Wang, Jia [Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218 (United States)

    2015-07-15

    Hyperthermia (42-46°C), treatment of tumor tissue through elevated temperature, offers several advantages including high cost-effectiveness, highly targeted ablation and fewer side effects and hence higher safety level over traditional therapies such as chemotherapy and radiotherapy. Recently, hyperthermia using heat release through exothermic acid-base neutralization comes into view owing to its relatively safe products of salt and water and highly confined ablation. However, lack of quantitative understanding of the spatial and temporal temperature profiles that are produced by simultaneous diffusion of liquid chemical and its chemical reaction within tumor tissue impedes the application of this method. This article is dedicated to quantify thermal ablation effects of acid and base both individually and as in neutralization via infrared captured thermal images. A theoretical model is used to approximate specific heat absorption rate (SAR) based on experimental measurements that contrast two types of tissue, normal pork and pig liver. According to the computation, both pork and liver tissue has a higher ability in absorbing hydrochloric acid (HCl) than sodium hydroxide, hence suggesting that a reduced dosage for HCl is appropriate in a surgery. The heating effect depends heavily on the properties of tissue types and amount of chemical reagents administered. Given thermal parameters such as SAR for different tissues, a computational model can be made in predicting temperature transitions which will be helpful in planning and optimizing surgical hyperthermia procedures.

  9. Cavitation-enhanced MR-guided focused ultrasound ablation of rabbit tumors in vivo using phase shift nanoemulsions

    OpenAIRE

    Kopechek, Jonathan A; Park, Eun-Joo; Zhang, Yong-Zhi; Vykhodtseva, Natalia I; McDannold, Nathan J; Porter, Tyrone M

    2014-01-01

    Advanced tumors are often inoperable due to their size and proximity to critical vascular structures. High intensity focused ultrasound (HIFU) has been developed to non-invasively thermally ablate inoperable solid tumors. However, the clinical feasibility of HIFU ablation therapy has been limited by the long treatment times (on the order of hours) and high acoustic intensities required. Studies have shown that inertial cavitation can enhance HIFU-mediated heating by generating broadband acous...

  10. Real-time tumor ablation simulation based on the dynamic mode decomposition method

    KAUST Repository

    Bourantas, George C.

    2014-05-01

    Purpose: The dynamic mode decomposition (DMD) method is used to provide a reliable forecasting of tumor ablation treatment simulation in real time, which is quite needed in medical practice. To achieve this, an extended Pennes bioheat model must be employed, taking into account both the water evaporation phenomenon and the tissue damage during tumor ablation. Methods: A meshless point collocation solver is used for the numerical solution of the governing equations. The results obtained are used by the DMD method for forecasting the numerical solution faster than the meshless solver. The procedure is first validated against analytical and numerical predictions for simple problems. The DMD method is then applied to three-dimensional simulations that involve modeling of tumor ablation and account for metabolic heat generation, blood perfusion, and heat ablation using realistic values for the various parameters. Results: The present method offers very fast numerical solution to bioheat transfer, which is of clinical significance in medical practice. It also sidesteps the mathematical treatment of boundaries between tumor and healthy tissue, which is usually a tedious procedure with some inevitable degree of approximation. The DMD method provides excellent predictions of the temperature profile in tumors and in the healthy parts of the tissue, for linear and nonlinear thermal properties of the tissue. Conclusions: The low computational cost renders the use of DMD suitable forin situ real time tumor ablation simulations without sacrificing accuracy. In such a way, the tumor ablation treatment planning is feasible using just a personal computer thanks to the simplicity of the numerical procedure used. The geometrical data can be provided directly by medical image modalities used in everyday practice. © 2014 American Association of Physicists in Medicine.

  11. LAPAROSCOPIC NEPHRECTOMY USING RADIOFREQUENCY THERMAL ABLATION

    Directory of Open Access Journals (Sweden)

    B. Ya. Alekseev

    2012-01-01

    Full Text Available The wide use of current diagnostic techniques, such as ultrasound study, computed tomography, and magnetic resonance imaging, has led to significantly increased detection rates for disease in its early stages. This gave rise to a change in the standards for the treatment of locally advanced renal cell carcinoma (RCC. Laparoscopic nephrectomy (LN has recently become the standard treatment of locally advanced RCC in the clinics having much experience with laparoscopic surgery. The chief drawback of LN is difficulties in maintaining intraoperative hemostasis and a need for creating renal tissue ischemia. The paper gives the intermediate results of application of the new procedure of LN using radiofrequency thermal ablation in patients with non-ischemic early-stage RCC.

  12. Lung Tumor Radiofrequency Ablation: Where Do We Stand?

    International Nuclear Information System (INIS)

    Baère, Thierry de

    2011-01-01

    Today, radiofrequency ablation (RFA) of primary and metastatic lung tumor is increasingly used. Because RFA is most often used with curative intent, preablation workup must be a preoperative workup. General anesthesia provides higher feasibility than conscious sedation. The electrode positioning must be performed under computed tomography for sake of accuracy. The delivery of RFA must be adapted to tumor location, with different impedances used when treating tumors with or without pleural contact. The estimated rate of incomplete local treatment at 18 months was 7% (95% confidence interval, 3–14) per tumor, with incomplete treatment depicted at 4 months (n = 1), 6 months (n = 2), 9 months (n = 2), and 12 months (n = 2). Overall survival and lung disease-free survival at 18 months were, respectively, 71 and 34%. Size is a key point for tumor selection because large size is predictive of incomplete local treatment and poor survival. The ratio of ablation volume relative to tumor volume is predictive of complete ablation. Follow-up computed tomography that relies on the size of the ablation zone demonstrates the presence of incomplete ablation. Positron emission tomography might be an interesting option. Chest tube placement for pneumothorax is reported in 8 to 12%. Alveolar hemorrhage and postprocedure hemoptysis occurred in approximately 10% of procedures and rarely required specific treatment. Death was mostly related to single-lung patients and hilar tumors. No modification of forced expiratory volume in the first second between pre- and post-RFA at 2 months was found. RFA in the lung provides a high local efficacy rate. The use of RFA as a palliative tool in combination with chemotherapy remains to be explored.

  13. Alternative High Performance Polymers for Ablative Thermal Protection Systems

    Science.gov (United States)

    Boghozian, Tane; Stackpoole, Mairead; Gonzales, Greg

    2015-01-01

    Ablative thermal protection systems are commonly used as protection from the intense heat during re-entry of a space vehicle and have been used successfully on many missions including Stardust and Mars Science Laboratory both of which used PICA - a phenolic based ablator. Historically, phenolic resin has served as the ablative polymer for many TPS systems. However, it has limitations in both processing and properties such as char yield, glass transition temperature and char stability. Therefore alternative high performance polymers are being considered including cyanate ester resin, polyimide, and polybenzoxazine. Thermal and mechanical properties of these resin systems were characterized and compared with phenolic resin.

  14. Image-guided radiofrequency ablation (RFA) of spinal tumors

    International Nuclear Information System (INIS)

    Gevargez, Athour; Groenemeyer, Dietrich H.W.

    2008-01-01

    Purpose: To evaluate retrospectively the efficacy and safety of radiofrequency ablation (RFA) in patients with spinal tumors. Materials and methods: Forty-one patients (25 men, 16 women; age range, 46-82 years) with nonresectable primary or secondary tumor involvement of the spine unresponsive to chemo- and radiotherapy received RFA treatment. Two radiofrequency ablation systems, one with a cool-tip electrode and one with an expandable electrode catheter, were used. Both systems work impedance controlled with a power output of 150- 200 W. Each coagulation cycle lasted 12-15 min depending on tumor impedance. Several single RFA cycles of 15 min each were used for overlapping RFAs in tumors with diameters of more than 3 cm. Temperature was kept between 50 deg. C and 120 deg. C and was chosen according to spinal cord distance and patient heat tolerance during the ablation. Multi-slice computed tomography (CT) combined with C-arm fluoroscopy guided the intervention. Efficacy outcomes were assessed after about 6 weeks, 6 months, and more than 6 months using standardized questionnaires and indices regarding tumor pain, pain disability, functional activities, quality of life, neurological status, and tumor progression. Results: RFA significantly reduced tumor-induced pain within 6 weeks, improved daily activities, and maintained quality of life. Mean time to tumor progression was 730 ± 54 days (Kaplan-Meier estimate). No RFA-associated complications were reported. Conclusion: RFA of primary and secondary spinal tumors, which were unresponsive to chemo- and radiotherapy and prone to progression, is a safe, resource-saving, and highly effective percutaneous technique in patients with nonresectable spinal tumors

  15. Activation of Anti-tumor Immune Response by Ablation of HCC with Nanosecond Pulsed Electric Field.

    Science.gov (United States)

    Xu, Xiaobo; Chen, Yiling; Zhang, Ruiqing; Miao, Xudong; Chen, Xinhua

    2018-03-28

    Locoregional therapy is playing an increasingly important role in the non-surgical management of hepatocellular carcinoma (HCC). The novel technique of non-thermal electric ablation by nanosecond pulsed electric field has been recognized as a potential locoregional methodology for indicated HCC. This manuscript explores the most recent studies to indicate its unique anti-tumor immune response. The possible immune mechanism, termed as nano-pulse stimulation, was also analyzed.

  16. Flexible applicator systems for radiofrequency ablation (RFA) of hepatic tumors

    International Nuclear Information System (INIS)

    Gebauer, B.; Gaffke, G.; Felix, R.; Stroszczynski, C.; Huenerbein, M.

    2003-01-01

    Purpose: To report our experience with flexible applicators in radiofrequency ablation (RFA) of hepatic tumors. Materials and Methods: In 6 liver tumors in 6 patients, a flexible RFA-applicator system (RITA StarBurst FLEX, RITA Medical Systems, Mountain View, CA, USA) was placed under CT guidance. The Seldinger technique with an 11G access system (RITA StarBurst Access) was used to place the application system into the liver. Before and within a week after the ablation, all tumors were investigated with contrast-enhanced MRI. Results: The Seldinger technique accommodated the placement of a thin 17.5-gauge needle for the initial puncture, enabling easy adjustment of the position of the needle. The flexible applicator of the RFA system could be placed in 4.5 (±1.8) minutes on average. Conclusion: Flexible applicators facilitate CT-guided RFA and can be placed using the Seldinger technique. (orig.) [de

  17. Efficacy and satisfaction rate comparing endometrial ablation by rollerball electrocoagulation to uterine balloon thermal ablation in a randomised controlled trial.

    NARCIS (Netherlands)

    Zon-Rabelink, I.A.A. van; Vleugels, M.P.; Merkus, J.M.W.M.; Graaf, R.M. de

    2004-01-01

    OBJECTIVE: To compare two methods of endometrial ablation, hysteroscopic rollerball electrocoagulation (RBE) and non-hysteroscopic uterine balloon thermal ablation (Thermachoice trade mark ), regarding efficacy for reducing dysfunctional uterine bleeding and patients satisfaction rate. METHODS: A

  18. Radiofrequency and microwave tumor ablation in patients with implanted cardiac devices: Is it safe?

    Energy Technology Data Exchange (ETDEWEB)

    Skonieczki, Brendan D., E-mail: bskonieczki@lifespan.org [Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University/Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States); Wells, Catherine, E-mail: cwells1@bidmc.harvard.edu [Department of Radiology, Harvard Medical School/Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215 (United States); Wasser, Elliot J., E-mail: ewasser@lifespan.org [Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University/Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States); Dupuy, Damian E., E-mail: ddupuy@lifespan.org [Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University/Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States)

    2011-09-15

    Purpose: To identify malfunction of implanted cardiac devices during or after thermal ablation of tumors in lung, kidney, liver or bone, using radiofrequency (RF) or microwave (MW) energy. Materials and methods: After providing written consent, 19 patients (15 men and 4 women; mean age 78 years) with pacemakers or pacemaker/defibrillators underwent 22 CT image-guided percutaneous RF or MW ablation of a variety of tumors. Before and after each procedure, cardiac devices were interrogated and reprogrammed by a trained cardiac electrophysiology fellow. Possible pacer malfunctions included abnormalities on electrocardiographic (EKG) monitoring and alterations in device settings. Our institutional review board approved this Health Insurance Portability and Accountability Act-compliant study. Informed consent for participation in this retrospective study was deemed unnecessary by our review board. Results: During 20 of 22 sessions, no abnormalities were identified in continuous, EKG tracings or pacemaker functions. However, in two sessions significant changes, occurred in pacemaker parameters: inhibition of pacing during RF application in one, session and resetting of mode by RF energy in another session. These changes did not, result in hemodynamic instability of either patient. MW ablation was not associated with, any malfunction. In all 22 sessions, pacemakers were undamaged and successfully reset to original parameters. Conclusion: RF or MW ablation of tumors in liver, kidney, bone and lung can be performed safely in patients with permanent intra-cardiac devices, but careful planning between radiology and cardiology is essential to avoid adverse outcomes.

  19. TU-B-210-01: MRg HIFU - Bone and Soft Tissue Tumor Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Ghanouni, P. [Stanford University (United States)

    2015-06-15

    MR guided focused ultrasound (MRgFUS), or alternatively high-intensity focused ultrasound (MRgHIFU), is approved for thermal ablative treatment of uterine fibroids and pain palliation in bone metastases. Ablation of malignant tumors is under active investigation in sites such as breast, prostate, brain, liver, kidney, pancreas, and soft tissue. Hyperthermia therapy with MRgFUS is also feasible, and may be used in conjunction with radiotherapy and for local targeted drug delivery. MRI allows in situ target definition and provides continuous temperature monitoring and subsequent thermal dose mapping during HIFU. Although MRgHIFU can be very precise, treatment of mobile organs is challenging and advanced techniques are required because of artifacts in MR temperature mapping, the need for intercostal firing, and need for gated HIFU or tracking of the lesion in real time. The first invited talk, “MR guided Focused Ultrasound Treatment of Tumors in Bone and Soft Tissue”, will summarize the treatment protocol and review results from treatment of bone tumors. In addition, efforts to extend this technology to treat both benign and malignant soft tissue tumors of the extremities will be presented. The second invited talk, “MRI guided High Intensity Focused Ultrasound – Advanced Approaches for Ablation and Hyperthermia”, will provide an overview of techniques that are in or near clinical trials for thermal ablation and hyperthermia, with an emphasis of applications in abdominal organs and breast, including methods for MRTI and tracking targets in moving organs. Learning Objectives: Learn background on devices and techniques for MR guided HIFU for cancer therapy Understand issues and current status of clinical MRg HIFU Understand strategies for compensating for organ movement during MRgHIFU Understand strategies for strategies for delivering hyperthermia with MRgHIFU CM - research collaboration with Philips.

  20. TU-B-210-01: MRg HIFU - Bone and Soft Tissue Tumor Ablation

    International Nuclear Information System (INIS)

    Ghanouni, P.

    2015-01-01

    MR guided focused ultrasound (MRgFUS), or alternatively high-intensity focused ultrasound (MRgHIFU), is approved for thermal ablative treatment of uterine fibroids and pain palliation in bone metastases. Ablation of malignant tumors is under active investigation in sites such as breast, prostate, brain, liver, kidney, pancreas, and soft tissue. Hyperthermia therapy with MRgFUS is also feasible, and may be used in conjunction with radiotherapy and for local targeted drug delivery. MRI allows in situ target definition and provides continuous temperature monitoring and subsequent thermal dose mapping during HIFU. Although MRgHIFU can be very precise, treatment of mobile organs is challenging and advanced techniques are required because of artifacts in MR temperature mapping, the need for intercostal firing, and need for gated HIFU or tracking of the lesion in real time. The first invited talk, “MR guided Focused Ultrasound Treatment of Tumors in Bone and Soft Tissue”, will summarize the treatment protocol and review results from treatment of bone tumors. In addition, efforts to extend this technology to treat both benign and malignant soft tissue tumors of the extremities will be presented. The second invited talk, “MRI guided High Intensity Focused Ultrasound – Advanced Approaches for Ablation and Hyperthermia”, will provide an overview of techniques that are in or near clinical trials for thermal ablation and hyperthermia, with an emphasis of applications in abdominal organs and breast, including methods for MRTI and tracking targets in moving organs. Learning Objectives: Learn background on devices and techniques for MR guided HIFU for cancer therapy Understand issues and current status of clinical MRg HIFU Understand strategies for compensating for organ movement during MRgHIFU Understand strategies for strategies for delivering hyperthermia with MRgHIFU CM - research collaboration with Philips

  1. Ablation of tumor and inflammatory tissue with absolute ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Uflacker, R.; Paolini, R.M.; Nobrega, M.

    Absolute ethanol was used to ablate tumors, inflammatory lesions, and end-stage nephrosclerotic kidneys in 38 patients. Thirty patients had various types of renal tumors, and 3 had chronic end-stage renal failure with malignant hypertension. One patient had a fibrosarcoma of the right leg and one had a metastatis in the humerus from a renal carcinoma. A large adrenal carcinoma was treated with absolute ethanol in a patient who had liver metastases that were ablated one year after the first procedure. An additional patient had metastatic liver disease from a non-functioning adrenal carcinoma. The remaining patient had an extensive hypervascular inflammatory lesion (tuberculosis and aspergilloma) of the right upper pulmonary lobe. In addition to ethanol, coils were introduced in one patient and Gelfoam in another. The amount of ethanol used ranged from 5 to 50 ml. Twenty-two patients suffered from considerable transient pain during ethanol injection, but sedation was necessary in only 3 of them. Skin necrosis appeared in 2 patients requiring plastic reconstruction in one of them. Two patients died within 5 days of the procedure unrelated to the ablation. Two patients presented upper gastrointestinal bleeding within 2 days of the ethanol injection and one of these died in acute renal failure. One patient suffered from left colonic infarction after left renal tumor ablation, but survived for several months. Absolute ethanol was a useful and efficient sclerosing agent causing extensive tumor destruction and marked reduction of the vascularity in tumor and inflammatory lesions, but caused an 18% complication rate.

  2. Thermal Protection with 5% Dextrose Solution Blanket During Radiofrequency Ablation

    International Nuclear Information System (INIS)

    Chen, Enn Alexandria; Neeman, Ziv; Lee, Fred T.; Kam, Anthony; Wood, Brad

    2006-01-01

    A serious complication for any thermal radiofrequency ablation is thermal injury to adjacent structures, particularly the bowel, which can result in additional major surgery or death. Several methods using air, gas, fluid, or thermometry to protect adjacent structures from thermal injury have been reported. In the cases presented in this report, 5% dextrose water (D5W) was instilled to prevent injury to the bowel and diaphragm during radiofrequency ablation. Creating an Insulating envelope or moving organs with D5W might reduce risk for complications such as bowel perforation

  3. Transpiration cooling assisted ablative thermal protection of aerospace substructures

    International Nuclear Information System (INIS)

    Khan, M.B.; Iqbal, N.; Haider, Z.

    2009-01-01

    Ablatives are heat-shielding materials used to protect aerospace substructures. These materials are sacrificial in nature and provide protection primarily through the large endothermic transformation during exposure to hyper thermal environment such as encountered in re-entry modules. The performance of certain ablatives was reported in terms of their TGA/DTA in Advanced Materials-97 (pp 57-65). The focus of this earlier research resided in the consolidation of interface between the refractory inclusion and the host polymeric matrix to improve thermal resistance. In the present work we explore the scope of transpiration cooling in ablative performance through flash evaporation of liquid incorporated in the host EPDM (Ethylene Propylene Diene Monomer) matrix. The compression-molded specimens were exposed separately to plasma flame (15000 C) and oxyacetylene torch (3000 C) and the back face transient temperature is recorded in situ employing a thermocouple/data logger system. Both head on impingement (HOI) and parallel flow (PF) through a central cavity in the ablator were used. It is observed that transpiration cooling is effective and yields (a) rapid thermal equilibrium in the specimen, (b) lower back face temperature and (c) lower ablation rate, compared to conventional ablatives. SEM/EDS analysis is presented to amplify the point. (author)

  4. Percutaneous Renal Tumor Ablation: Radiation Exposure During Cryoablation and Radiofrequency Ablation

    Energy Technology Data Exchange (ETDEWEB)

    McEachen, James C., E-mail: james.mceachen2@gmail.com [Mayo Clinic, Division of Preventive, Occupational, and Aerospace Medicine (United States); Leng, Shuai; Atwell, Thomas D. [Mayo Clinic, Department of Radiology (United States); Tollefson, Matthew K. [Mayo Clinic, Department of Urology (United States); Friese, Jeremy L. [Mayo Clinic, Department of Radiology (United States); Wang, Zhen; Murad, M. Hassan [Mayo Clinic, Division of Preventive, Occupational, and Aerospace Medicine (United States); Schmit, Grant D. [Mayo Clinic, Department of Radiology (United States)

    2016-02-15

    IntroductionOnce reserved solely for non-surgical cases, percutaneous ablation is becoming an increasingly popular treatment option for a wider array of patients with small renal masses and the radiation risk needs to be better defined as this transition continues.Materials and MethodsRetrospective review of our renal tumor ablation database revealed 425 patients who underwent percutaneous ablation for treatment of 455 renal tumors over a 5-year time period. Imparted radiation dose information was reviewed for each procedure and converted to effective patient dose and skin dose using established techniques. Statistical analysis was performed with each ablative technique.ResultsFor the 331 cryoablation procedures, the mean DLP was 6987 mGycm (SD = 2861) resulting in a mean effective dose of 104.7 mSv (SD = 43.5) and the mean CTDI{sub vol} was 558 mGy (SD = 439) resulting in a mean skin dose of 563.2 mGy (SD = 344.1). For the 124 RFA procedures, the mean DLP was 3485 mGycm (SD = 1630) resulting in a mean effective dose of 50.3 mSv (SD = 24.0) and the mean CTDI{sub vol} was 232 mGy (SD = 149) resulting in a mean skin dose of 233.2 mGy (SD = 117.4). The difference in patient radiation exposure between the two renal ablation techniques was statistically significant (p < 0.001).ConclusionBoth cryoablation and RFA imparted an average skin dose that was well below the 2 Gy deterministic threshold for appreciable sequela. Renal tumor cryoablation resulted in a mean skin and effective radiation dose more than twice that for RFA. The radiation exposure for both renal tumor ablation techniques was at the high end of the medical imaging radiation dose spectrum.

  5. Ultrasound-guided percutaneous thermal ablation of hepatocellular carcinoma using microwave and radiofrequency ablation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H.-X.; Xie, X.-Y.; Lu, M.-D. E-mail: lumd@21cn.com; Chen, J.-W.; Yin, X.-Y.; Xu, Z.-F.; Liu, G.-J

    2004-01-01

    AIM: To investigate the therapeutic efficacy of thermal ablation for treatment of hepatocellular carcinoma (HCC) using microwave and radiofrequency (RF) energy application. MATERIALS AND METHODS: A total of 190 nodules in 97 patients (84 male, 13 female; mean age 53.4 years, range 24-74 years) with HCC were treated with microwave or RF ablation in the last 4 years. The applicators were introduced into the tumours under conscious analgesic sedation by intravenous administration of fentanyl citrate and droperidol and local anaesthesia in both thermal ablation procedures. The patients were then followed up with contrast-enhanced computed tomography (CT) to evaluate treatment response. Survival was analysed using the Kaplan-Meier method. RESULTS: Complete ablation was obtained in 92.6% (176/190) nodules. The complete ablation rates were 94.6% (106/112) in microwave ablation and 89.7% (70/78) in RF ablation. The complete ablation rates in tumours{<=}2.0, 2.1-3.9 and {>=}4.0 cm were 93.1, 93.8 and 86.4%, respectively. Local recurrence was found in 9.5% nodules and the rates in tumours{<=}2.0, 2.1-3.9 and {>=}4.0 cm in diameter were 3.4, 9.9 and 31.8%, respectively. In the follow-up period, 7.1% nodules ablated by microwave and 12.8% by RF presented local recurrence. The 1, 2 and 3-year distant recurrence-free survivals were 47.2, 34.9 and 31.0%, respectively. Estimated mean survival was 32 months, and 1, 2 and 3-year cumulative survivals were 75.6, 58.5, and 50.0%, respectively. One and 2 years survivals of Child-Pugh class A, B and C patients were 83.8 and 70.4%, 78.2 and 53.2%, 36.3 and 27.3%, respectively. CONCLUSION: Thermal ablation therapy by means of microwave and RF energy application is an effective and safe therapeutic technique for hepatocellular carcinoma. Large tumours can be completely ablated, but have a significantly higher risk of local recurrence at follow-up.

  6. Ultrasound-guided percutaneous thermal ablation of hepatocellular carcinoma using microwave and radiofrequency ablation

    International Nuclear Information System (INIS)

    Xu, H.-X.; Xie, X.-Y.; Lu, M.-D.; Chen, J.-W.; Yin, X.-Y.; Xu, Z.-F.; Liu, G.-J.

    2004-01-01

    AIM: To investigate the therapeutic efficacy of thermal ablation for treatment of hepatocellular carcinoma (HCC) using microwave and radiofrequency (RF) energy application. MATERIALS AND METHODS: A total of 190 nodules in 97 patients (84 male, 13 female; mean age 53.4 years, range 24-74 years) with HCC were treated with microwave or RF ablation in the last 4 years. The applicators were introduced into the tumours under conscious analgesic sedation by intravenous administration of fentanyl citrate and droperidol and local anaesthesia in both thermal ablation procedures. The patients were then followed up with contrast-enhanced computed tomography (CT) to evaluate treatment response. Survival was analysed using the Kaplan-Meier method. RESULTS: Complete ablation was obtained in 92.6% (176/190) nodules. The complete ablation rates were 94.6% (106/112) in microwave ablation and 89.7% (70/78) in RF ablation. The complete ablation rates in tumours≤2.0, 2.1-3.9 and ≥4.0 cm were 93.1, 93.8 and 86.4%, respectively. Local recurrence was found in 9.5% nodules and the rates in tumours≤2.0, 2.1-3.9 and ≥4.0 cm in diameter were 3.4, 9.9 and 31.8%, respectively. In the follow-up period, 7.1% nodules ablated by microwave and 12.8% by RF presented local recurrence. The 1, 2 and 3-year distant recurrence-free survivals were 47.2, 34.9 and 31.0%, respectively. Estimated mean survival was 32 months, and 1, 2 and 3-year cumulative survivals were 75.6, 58.5, and 50.0%, respectively. One and 2 years survivals of Child-Pugh class A, B and C patients were 83.8 and 70.4%, 78.2 and 53.2%, 36.3 and 27.3%, respectively. CONCLUSION: Thermal ablation therapy by means of microwave and RF energy application is an effective and safe therapeutic technique for hepatocellular carcinoma. Large tumours can be completely ablated, but have a significantly higher risk of local recurrence at follow-up

  7. Image-guided Tumor Ablation: Standardization of Terminology and Reporting Criteria—A 10-Year Update

    Science.gov (United States)

    Solbiati, Luigi; Brace, Christopher L.; Breen, David J.; Callstrom, Matthew R.; Charboneau, J. William; Chen, Min-Hua; Choi, Byung Ihn; de Baère, Thierry; Dodd, Gerald D.; Dupuy, Damian E.; Gervais, Debra A.; Gianfelice, David; Gillams, Alice R.; Lee, Fred T.; Leen, Edward; Lencioni, Riccardo; Littrup, Peter J.; Livraghi, Tito; Lu, David S.; McGahan, John P.; Meloni, Maria Franca; Nikolic, Boris; Pereira, Philippe L.; Liang, Ping; Rhim, Hyunchul; Rose, Steven C.; Salem, Riad; Sofocleous, Constantinos T.; Solomon, Stephen B.; Soulen, Michael C.; Tanaka, Masatoshi; Vogl, Thomas J.; Wood, Bradford J.; Goldberg, S. Nahum

    2014-01-01

    Image-guided tumor ablation has become a well-established hallmark of local cancer therapy. The breadth of options available in this growing field increases the need for standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison among treatments that use different technologies, such as chemical (eg, ethanol or acetic acid) ablation, thermal therapies (eg, radiofrequency, laser, microwave, focused ultrasound, and cryoablation) and newer ablative modalities such as irreversible electroporation. This updated consensus document provides a framework that will facilitate the clearest communication among investigators regarding ablative technologies. An appropriate vehicle is proposed for reporting the various aspects of image-guided ablation therapy including classification of therapies, procedure terms, descriptors of imaging guidance, and terminology for imaging and pathologic findings. Methods are addressed for standardizing reporting of technique, follow-up, complications, and clinical results. As noted in the original document from 2003, adherence to the recommendations will improve the precision of communications in this field, leading to more accurate comparison of technologies and results, and ultimately to improved patient outcomes. © RSNA, 2014 Online supplemental material is available for this article. PMID:24927329

  8. Use of Semiflexible Applicators for Radiofrequency Ablation of Liver Tumors

    International Nuclear Information System (INIS)

    Gaffke, G.; Gebauer, B.; Knollmann, F.D.; Helmberger, T.; Ricke, J.; Oettle, H.; Felix, R.; Stroszczynski, C.

    2006-01-01

    Purpose. To evaluate the feasibility and potential advantages of the radiofrequency ablation of liver tumors using new MRI-compatible semiflexible applicators in a closed-bore high-field MRI scanner. Methods. We treated 8 patients with 12 malignant liver tumors of different origin (5 colorectal carcinoma, 2 cholangiocellular carcinoma, 1 breast cancer) under MRI guidance. Radiofrequency ablation (RFA) was performed using 5 cm Rita Starburst Semi-Flex applicators (Rita Medical Systems, Milwaukee, WI, USA) which are suitable for MR- and CT-guided interventions and a 150 W RF generator. All interventions were performed in a closed-bore 1.5 T high-field MRI scanner for MRI-guided RFA using fast T1-weighted gradient echo sequences and T2-weighted ultra-turbo spin echo sequences. Control and follow-up MRI examinations were performed on the next day, at 6 weeks, and every 3 months after RFA. Control MRI were performed as double-contrast MRI examinations (enhancement with iron oxide and gadopentetate dimeglumine). All interventions were performed with the patient under local anesthesia and analgo-sedation. Results. The mean diameter of the treated hepatic tumors was 2.4 cm (±0.6 cm, range 1.0-3.2 cm). The mean diameter of induced necrosis was 3.1 cm (±0.4 cm). We achieved complete ablation in all patients. Follow-up examinations over a duration of 7 months (±1.3 months, range 4-9 month) showed a local control rate of 100% in this group of patients. All interventions were performed without major complications; only 2 subcapsular hematomas were documented. Conclusion. RFA of liver tumors using semiflexible applicators in closed-bore 1.5 T scanner systems is feasible. These applicators might simplify the RFA of liver tumors under MRI control. The stiff distal part of the applicator facilitates its repositioning

  9. A Novel Combination of Thermal Ablation and Heat-Inducible Gene therapy for Breast Cancer Treatment

    Science.gov (United States)

    2009-04-01

    11. Khokhlova, V.A., et al., Effects of nonlinear propagation, cavitation , and boiling in lesion formation by high intensity focused ultrasound in...intensity focused ultrasound (HIFU) has been developed as an emerging non-invasive strategy for cancer treatment by thermal ablation of tumor tissue. The...Concepts, Seattle, WA) operating at its fundamental frequency (1.1 MHz) or its third harmonics (3.3 MHz). The ultrasound imaging system was a 5/7

  10. Thermal-mechanical deformation modelling of soft tissues for thermal ablation.

    Science.gov (United States)

    Li, Xin; Zhong, Yongmin; Jazar, Reza; Subic, Aleksandar

    2014-01-01

    Modeling of thermal-induced mechanical behaviors of soft tissues is of great importance for thermal ablation. This paper presents a method by integrating the heating process with thermal-induced mechanical deformations of soft tissues for simulation and analysis of the thermal ablation process. This method combines bio-heat transfer theories, constitutive elastic material law under thermal loads as well as non-rigid motion dynamics to predict and analyze thermal-mechanical deformations of soft tissues. The 3D governing equations of thermal-mechanical soft tissue deformation are discretized by using the finite difference scheme and are subsequently solved by numerical algorithms. Experimental results show that the proposed method can effectively predict the thermal-induced mechanical behaviors of soft tissues, and can be used for the thermal ablation therapy to effectively control the delivered heat energy for cancer treatment.

  11. Ablation, Thermal Response, and Chemistry Program for Analysis of Thermal Protection Systems

    Science.gov (United States)

    Milos, Frank S.; Chen, Yih-Kanq

    2010-01-01

    In previous work, the authors documented the Multicomponent Ablation Thermochemistry (MAT) and Fully Implicit Ablation and Thermal response (FIAT) programs. In this work, key features from MAT and FIAT were combined to create the new Fully Implicit Ablation, Thermal response, and Chemistry (FIATC) program. FIATC is fully compatible with FIAT (version 2.5) but has expanded capabilities to compute the multispecies surface chemistry and ablation rate as part of the surface energy balance. This new methodology eliminates B' tables, provides blown species fractions as a function of time, and enables calculations that would otherwise be impractical (e.g. 4+ dimensional tables) such as pyrolysis and ablation with kinetic rates or unequal diffusion coefficients. Equations and solution procedures are presented, then representative calculations of equilibrium and finite-rate ablation in flight and ground-test environments are discussed.

  12. Renal Tumors: Technical Success and Early Clinical Experience with Radiofrequency Ablation of 18 Tumors

    International Nuclear Information System (INIS)

    Sabharwal, Rohan; Vladica, Philip

    2006-01-01

    Purpose. To evaluate the feasibility, safety, and technical efficacy of image-guided radiofrequency ablation (RFA) for the treatment of small peripheral renal tumors and to report our early results with this treatment modality. Methods. Twenty-two RFA sessions for 18 tumors were performed in 11 patients with renal tumors. Indications included coexistent morbidity, high surgical or anesthetic risk, solitary kidney, and hereditary predisposition to renal cell carcinoma. Ten patients had CT-guided percutaneous RFA performed on an outpatient basis. One patient had open intraoperative ultrasound-guided RFA. Technical success was defined as elimination of areas that enhanced at imaging within the entire tumor. With the exception of one patient with renal insufficiency who required gadolinium-enhanced MRI, the remaining patients underwent contrast-enhanced CT for post-treatment follow-up assessment. Follow-up was performed after 2-4 weeks and then at 3, 6, 12 months, and every 12 months thereafter. Results. Fourteen (78%) of 18 tumors were successfully ablated with one session. Three of the remaining four tumors required two sessions for successful ablation. One tumor will require a third session for areas of persistent enhancement. Mean patient age was 72.82 ± 10.43 years. Mean tumor size was 1.95 ± 0.79 cm. Mean follow-up time was 10.91 months. All procedures were performed without any major complications. Conclusions. Our early experience with percutaneous image-guided radiofrequency ablation demonstrates it to be a feasible, safe, noninvasive, and effective treatment of small peripheral renal tumors

  13. Percutaneous Thermal Ablation of Breast Cancer Metastases in Oligometastatic Patients

    Energy Technology Data Exchange (ETDEWEB)

    Barral, M., E-mail: matthias-barral@yahoo.fr [Institut Gustave Roussy, Interventional Radiology Department (France); Auperin, A., E-mail: anne.auperin@gustaveroussy.fr [Institut Gustave Roussy, Biostatistics and Epidemiology Unit (France); Hakime, A., E-mail: thakime@yahoo.com; Cartier, V., E-mail: victoirecartier@hotmail.com; Tacher, V., E-mail: vaniatacher@gmail.com [Institut Gustave Roussy, Interventional Radiology Department (France); Otmezguine, Yves, E-mail: yotmezguine@ccps.com [Centre Clinique de la Porte de Saint-Cloud, Radiotherapy (France); Tselikas, L., E-mail: lambros.tselikas@gmail.com; Baere, T. de, E-mail: thierry.debaere@gustaveroussy.fr; Deschamps, F., E-mail: frederic.deschamps@gustaveroussy.fr [Institut Gustave Roussy, Interventional Radiology Department (France)

    2016-06-15

    ObjectiveTo evaluate prognostic factors associated with local control and disease-free-survival (DFS) of oligometastatic breast cancer patients treated by percutaneous thermal ablation (PTA).Materials and MethodsSeventy-nine consecutive patients (54.5 ± 11.2 years old) with 114 breast cancer metastases (28.9 ± 16.1 mm in diameter), involving the lungs, the liver, and/or the bone, were treated using PTA with a curative intent. The goal was to achieve a complete remission in association with systemic chemotherapy and hormonal therapy. We retrospectively evaluated the prognostic factors associated with 1- and 2-year local control and the 1- and 2-year DFS rates.ResultsThe 1- and 2-year local control rates were 83.0 and 76.1 %, respectively. Tumor burden was associated with a poorer outcome for local control after PTA (HR 1.027 by additional millimeter, p = 0.026; >4 cm HR 3.90). The 1- and 2-year DFS rates were 54.2 and 30.4 %, respectively. In multivariate analysis, triple-negative histological subtype and increased size of treated metastases were associated with a poorer DFS (HR 2.22; 95 % CI [1.13–4.36]; p = 0.02 and HR 2.43; 95 % CI [1.22–4.82]; p = 0.011, respectively).ConclusionPTA is effective for local control of breast cancer oligometastases. Tumor burden >4 cm and triple-negative histological subtype are associated with a poorer outcome.

  14. Percutaneous radiofrequency ablation of lung tumors in a large animal model.

    Science.gov (United States)

    Ahrar, Kamran; Price, Roger E; Wallace, Michael J; Madoff, David C; Gupta, Sanjay; Morello, Frank A; Wright, Kenneth C

    2003-08-01

    Percutaneous radiofrequency ablation (RFA) is accepted therapy for liver tumors in the appropriate clinical setting, but its use in lung neoplasms remains investigational. We undertook this study to evaluate the feasibility and immediate effectiveness of RFA for treatment of both solitary pulmonary nodules and clusters of lung tumors in a large animal model. Percutaneous RFA of 14 lung tumors in five dogs was performed under CT guidance. Animals were euthanatized 8-48 hours after the procedure. The lungs and adjacent structures were harvested for gross and histopathologic evaluation. Five solitary pulmonary nodules (range, 17-26 mm) and three clusters of three nodules each (range, 7-17 mm per nodule) were treated with RFA. All ablations were technically successful. Perilesional ground-glass opacity and small asymptomatic pneumothoraces (n = 4) were visualized during the RFA sessions. One dog developed a large pneumothorax treated with tube thoracostomy but was euthanatized 8 hours post-RFA for persistent pneumothorax and continued breathing difficulty. Follow-up CT 48 hours post-RFA revealed opacification of the whole lung segment. Gross and histopathologic evaluation showed complete thermal coagulation necrosis of all treated lesions without evidence of any viable tumor. The region of thermal coagulation necrosis typically extended to the lung surface. Small regions of pulmonary hemorrhage and congestion often surrounded the areas of coagulation necrosis. RFA can be used to treat both solitary pulmonary nodules and clusters of tumor nodules in the canine lung tumor model. This model may be useful for development of specific RFA protocols for human lung tumors.

  15. Experimental evidences of electro-thermal ablation acceleration of water

    International Nuclear Information System (INIS)

    Ikuta, Kazunari.

    1987-07-01

    We report the first demonstrations of driving water of about 1000 grams by electro-thermally ablated gas pressure in a cavity with a single exhauster. A blob of water was shot into the air with a shooting angle of about 45 deg, and the flight velocity observed was about 13 meters per second with the capacitor (28μF) charged up to 10 KV. The discharge sound was almost suppressed by the water blob loaded in the chamber possilbly because the energy of sound was dissipated into the water blob. The application of this ablation water driver to ship propulsion is also discussed. (author)

  16. Robotic-assisted thermal ablation of liver tumours

    International Nuclear Information System (INIS)

    Abdullah, Basri Johan Jeet; Yeong, Chai Hong; Goh, Khean Lee; Yoong, Boon Koon; Ho, Gwo Fuang; Yim, Carolyn Chue Wai; Kulkarni, Anjali

    2015-01-01

    This study aimed to assess the technical success, radiation dose, safety and performance level of liver thermal ablation using a computed tomography (CT)-guided robotic positioning system. Radiofrequency and microwave ablation of liver tumours were performed on 20 patients (40 lesions) with the assistance of a CT-guided robotic positioning system. The accuracy of probe placement, number of readjustments and total radiation dose to each patient were recorded. The performance level was evaluated on a five-point scale (5-1: excellent-poor). The radiation doses were compared against 30 patients with 48 lesions (control) treated without robotic assistance. Thermal ablation was successfully completed in 20 patients with 40 lesions and confirmed on multiphasic contrast-enhanced CT. No procedure related complications were noted in this study. The average number of needle readjustment was 0.8 ± 0.8. The total CT dose (DLP) for the entire robotic assisted thermal ablation was 1382 ± 536 mGy.cm, while the CT fluoroscopic dose (DLP) per lesion was 352 ± 228 mGy.cm. There was no statistically significant (p > 0.05) dose reduction found between the robotic-assisted versus the conventional method. This study revealed that robotic-assisted planning and needle placement appears to be safe, with high accuracy and a comparable radiation dose to patients. (orig.)

  17. Robotic-assisted thermal ablation of liver tumours

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Basri Johan Jeet; Yeong, Chai Hong [University of Malaya, Department of Biomedical Imaging and University of Malaya Research Imaging Centre, Faculty of Medicine, Kuala Lumpur (Malaysia); University of Malaya, Department of Internal Medicine, Faculty of Medicine, Kuala Lumpur (Malaysia); Goh, Khean Lee [University of Malaya, Department of Internal Medicine, Faculty of Medicine, Kuala Lumpur (Malaysia); Yoong, Boon Koon [University of Malaya, Department of Surgery, Faculty of Medicine, Kuala Lumpur (Malaysia); Ho, Gwo Fuang [University of Malaya, Department of Oncology, Faculty of Medicine, Kuala Lumpur (Malaysia); Yim, Carolyn Chue Wai [University of Malaya, Department of Anesthesia, Faculty of Medicine, Kuala Lumpur (Malaysia); Kulkarni, Anjali [Perfint Healthcare Corporation, Florence, OR (United States)

    2015-01-15

    This study aimed to assess the technical success, radiation dose, safety and performance level of liver thermal ablation using a computed tomography (CT)-guided robotic positioning system. Radiofrequency and microwave ablation of liver tumours were performed on 20 patients (40 lesions) with the assistance of a CT-guided robotic positioning system. The accuracy of probe placement, number of readjustments and total radiation dose to each patient were recorded. The performance level was evaluated on a five-point scale (5-1: excellent-poor). The radiation doses were compared against 30 patients with 48 lesions (control) treated without robotic assistance. Thermal ablation was successfully completed in 20 patients with 40 lesions and confirmed on multiphasic contrast-enhanced CT. No procedure related complications were noted in this study. The average number of needle readjustment was 0.8 ± 0.8. The total CT dose (DLP) for the entire robotic assisted thermal ablation was 1382 ± 536 mGy.cm, while the CT fluoroscopic dose (DLP) per lesion was 352 ± 228 mGy.cm. There was no statistically significant (p > 0.05) dose reduction found between the robotic-assisted versus the conventional method. This study revealed that robotic-assisted planning and needle placement appears to be safe, with high accuracy and a comparable radiation dose to patients. (orig.)

  18. The Confluence of Stereotactic Ablative Radiotherapy and Tumor Immunology

    Directory of Open Access Journals (Sweden)

    Steven Eric Finkelstein

    2011-01-01

    Full Text Available Stereotactic radiation approaches are gaining more popularity for the treatment of intracranial as well as extracranial tumors in organs such as the liver and lung. Technology, rather than biology, is driving the rapid adoption of stereotactic body radiation therapy (SBRT, also known as stereotactic ablative radiotherapy (SABR, in the clinic due to advances in precise positioning and targeting. Dramatic improvements in tumor control have been demonstrated; however, our knowledge of normal tissue biology response mechanisms to large fraction sizes is lacking. Herein, we will discuss how SABR can induce cellular expression of MHC I, adhesion molecules, costimulatory molecules, heat shock proteins, inflammatory mediators, immunomodulatory cytokines, and death receptors to enhance antitumor immune responses.

  19. Radiofrequency ablation of pulmonary tumors near the diaphragm.

    Science.gov (United States)

    Iguchi, T; Hiraki, T; Gobara, H; Fujiwara, H; Sakurai, J; Matsui, Y; Mitsuhashi, T; Toyooka, S; Kanazawa, S

    To retrospectively evaluate the feasibility, safety, and efficacy of radiofrequency ablation (RFA) of lung tumors located near the diaphragm. A total of 26 patients (15 men, 11 women; mean age, 61.5 years±13.0 [SD]) with a total of 29 lung tumors near the diaphragm (i.e., distance<10mm) were included. Mean tumor diameter was 11.0mm±5.3 (SD) (range, 2-23mm). Efficacy of RFA, number of adverse events and number of adverse events with a grade≥3, based on the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0, were compared between patients with lung tumors near the diaphragm and a control group of patients with more distally located lung tumors (i.e., distance≥10mm). RFA was technically feasible for all tumors near the diaphragm. Four grade 3 adverse events (1 pneumothorax requiring pleurodesis and 3 phrenic nerve injuries) were observed. No grade≥4 adverse events were reported. The median follow-up period for tumors near the diaphragm was 18.3 months. Local progression was observed 3.3 months after RFA in 1 tumor. The technique efficacy rates were 96.2% at 1 year and 96.2% at 2 years and were not different, from those observed in control subjects (186 tumors; P=0.839). Shoulder pain (P<0.001) and grade 1 pleural effusion (P<0.001) were more frequently observed in patients with lung tumor near the diaphragm. The rates of grade≥3 adverse events did not significantly differ between tumors near the diaphragm (4/26 sessions) and the controls (7/133 sessions) (P=0.083). RFA is a feasible and effective therapeutic option for lung tumors located near the diaphragm. However, it conveys a higher rate of shoulder pain and asymptomatic pleural effusion by comparison with more distant lung tumors. Copyright © 2017 Éditions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

  20. Percutaneous radiofrequency ablation of renal tumors: Midterm results in 16 patients

    International Nuclear Information System (INIS)

    Memarsadeghi, Mazda; Schmook, Theresia; Remzi, Mesut; Weber, Michael; Poetscher, Gerda; Lammer, Johannes; Kettenbach, Joachim

    2006-01-01

    Purpose: To evaluate the outcome of 16 patients after percutaneous radiofrequency ablation of renal tumors. Materials and methods: Sixteen patients (nine women, seven men; mean age, 61 ± 9 years) with 24 unresectable renal tumors (mean volume, 4.3 ± 4.3 cm 3 ) underwent CT-guided (n = 20) or MR imaging-guided (n = 4) percutaneous radiofrequency ablation using an expandable electrode (Starburst XL TM , RITA Medical Systems, Mountain View, CA) with a 150-W generator. The initial follow-up imaging was performed within 1-30 days after RF ablation, then at 3-6 month intervals using either CT or MRI. Residual tumor volume and coagulation necrosis was assessed, and statistical correlation tests were obtained to determine the strength of the relationship between necrosis volume and number of ablations. Results: Overall, 97 overlapping RF ablations were performed (mean, 3.5 ± 1.5 ablations per tumor) during 24 sessions. Five or more RF ablations per tumor created significant larger necrosis volumes than 1-2 (p .034) or 3-4 ablations (p = .020). A complete ablation was achieved in 20/24 tumors (primary technical success, 83%; mean volume of coagulation necrosis: 10.2 ± 7.2 cm 3 ). Three of four residual tumors were retreated and showed complete necrosis thereafter. Three major complications (one percuatneous urinary fistula and two ureteral strictures) were observed after RF ablation. No further clinically relevant complications were observed and renal function remained stable. During a mean follow-up of 11.2 months (range, 0.2-31.5), 15/16 patients (94%) were alive. Only one patient had evidence of local recurrent tumor. Conclusion: The midterm results of percutaneous RF ablation for renal tumors are promising and show that RF ablation is well-suited to preserve renal function

  1. Laparoscopic microwave thermosphere ablation of malignant liver tumors: an initial clinical evaluation.

    Science.gov (United States)

    Berber, Eren

    2016-02-01

    Microwave ablation (MWA) has been recently recognized as a technology to overcome the limitations of radiofrequency ablation. The aim of the current study was to evaluate the safety and efficacy of a new 2.45-GHz thermosphere MWA system in the treatment of malignant liver tumors. This was a prospective IRB-approved study of 18 patients with malignant liver tumors treated with MWA within a 3-month time period. Tumor sizes and response to MWA were obtained from triphasic liver CT scans done before and after MWA. The ablation zones were assessed for complete tumor response and spherical geometry. There were a total of 18 patients with an average of three tumors measuring 1.4 cm (range 0.2-4). Ablations were performed laparoscopically in all, but three patients who underwent combined liver resection. A single ablation was created in 72% and overlapping ablations in 28% of lesions. Total ablation time per patient was 15.6 ± 1.9 min. There was no morbidity or mortality. At 2-week CT scans, there was 100% tumor destruction, with no residual lesions. Roundness indices A, B and transverse were 1.1, 0.9 and 0.9, respectively, confirming the spherical nature of ablation zones. To the best of our knowledge, this is the first report of a new thermosphere MWA technology in the laparoscopic treatment of malignant liver tumors. The results demonstrate the safety of the technology, with satisfactory spherical ablation zones seen on post-procedural CT scans.

  2. Management of Renal Tumors by Image-Guided Radiofrequency Ablation: Experience in 105 Tumors

    International Nuclear Information System (INIS)

    Breen, David J.; Rutherford, Elizabeth E.; Stedman, Brian; Roy-Choudhury, Shuvro H.; Cast, James E. I.; Hayes, Matthew C.; Smart, Christopher J.

    2007-01-01

    Aims. In this article we present our experience with radiofrequency ablation (RFA) in the treatment of 105 renal tumors. Materials and Methods. RFA was performed on 105 renal tumors in 97 patients, with a mean tumor size of 32 mm (11-68 mm). The mean patient age was 71.7 years (range, 36-89 years). The ablations were carried out under ultrasound (n = 43) or CT (n = 62) guidance. Imaging follow-up was by contrast-enhanced CT within 10 days and then at 6-monthly intervals. Multivariate analysis was performed to determine variables associated with procedural outcome. Results. Eighty-three tumors were completely treated at a single sitting (79%). Twelve of the remaining tumors were successfully re-treated and a clinical decision was made not to re-treat seven patients. A patient with a small residual crescent of tumor is under follow-up and may require further treatment. In another patient, re-treatment was abandoned due to complicating pneumothorax and difficult access. One patient is awaiting further re-treatment. The overall technical success rate was 90.5%. Multivariate analysis revealed tumor size to be the only significant variable affecting procedural outcome. (p = 0.007, Pearson χ 2 ) Five patients had complications. There have been no local recurrences. Conclusion. Our experience to date suggests that RFA is a safe and effective, minimally invasive treatment for small renal tumors

  3. Interstitial ultrasound ablation of tumors within or adjacent to bone: Contributions of preferential heating at the bone surface

    Science.gov (United States)

    Scott, Serena J.; Prakash, Punit; Salgaonkar, Vasant; Jones, Peter D.; Cam, Richard N.; Han, Misung; Rieke, Viola; Burdette, E. Clif; Diederich, Chris J.

    2013-02-01

    Preferential heating of bone due to high ultrasound attenuation may enhance thermal ablation performed with cathetercooled interstitial ultrasound applicators in or near bone. At the same time, thermally and acoustically insulating cortical bone may protect sensitive structures nearby. 3D acoustic and biothermal transient finite element models were developed to simulate temperature and thermal dose distributions during catheter-cooled interstitial ultrasound ablation near bone. Experiments in ex vivo tissues and tissue-mimicking phantoms were performed to validate the models and to quantify the temperature profiles and ablated volumes for various distances between the interstitial applicator and the bone surface. 3D patient-specific models selected to bracket the range of clinical usage were developed to investigate what types of tumors could be treated, applicator configurations, insertion paths, safety margins, and other parameters. Experiments show that preferential heating at the bone surface decreases treatment times compared to when bone is absent and that all tissue between an applicator and bone can be ablated when they are up to 2 cm apart. Simulations indicate that a 5-7 mm safety margin of normal bone is needed to protect (thermal dose tumors 1.0-3.8 cm (L) and 1.3-3.0 cm (D) near or within bone were ablated (thermal dose > 240 CEM43°C) within 10 min without damaging the nearby spinal cord, lungs, esophagus, trachea, or major vasculature. Preferential absorption of ultrasound by bone may provide improved localization, faster treatment times, and larger treatment zones in tumors in and near bone compared to other heating modalities.

  4. Optimal CT scanning parameters for commonly used tumor ablation applicators

    International Nuclear Information System (INIS)

    Eltorai, Adam E.M.; Baird, Grayson L.; Monu, Nicholas; Wolf, Farrah; Seidler, Michael; Collins, Scott; Kim, Jeomsoon; Dupuy, Damian E.

    2017-01-01

    Highlights: • This study aimed to determine optimal scanning parameters for commonly-used tumor ablation applicators. • The findings illustrate the overall interaction of the effects of kVp, ASiR, and reconstruction algorithm within and between probes, so that radiologists may easily reference optimal imaging performance. • Optimum combinations for each probe are provided. - Abstract: Purpose: CT-beam hardening artifact can make tumor margin visualization and its relationship to the ablation applicator tip challenging. To determine optimal scanning parameters for commonly-used applicators. Materials and methods: Applicators were placed in ex-vivo cow livers with implanted mock tumors, surrounded by bolus gel. Various CT scans were performed at 440 mA with 5 mm thickness changing kVp, scan time, ASiR, scan type, pitch, and reconstruction algorithm. Four radiologists blindly scored the images for image quality and artifact quantitatively. Results: A significant relationship between probe, kVp level, ASiR level, and reconstruction algorithm was observed concerning both image artifact and image quality (both p = <0.0001). Specifically, there are certain combinations of kVp, ASiR, and reconstruction algorithm that yield better images than other combinations. In particular, one probe performed equivalently or better than any competing probe considered here, regardless of kVp, ASiR, and reconstruction algorithm combination. Conclusion: The findings illustrate the overall interaction of the effects of kVp, ASiR, and reconstruction algorithm within and between probes, so that radiologists may easily reference optimal imaging performance for a certain combinations of kVp, ASiR, reconstruction algorithm and probes at their disposal. Optimum combinations for each probe are provided.

  5. Optimal CT scanning parameters for commonly used tumor ablation applicators

    Energy Technology Data Exchange (ETDEWEB)

    Eltorai, Adam E.M. [Warren Alpert Medical School of Brown University (United States); Baird, Grayson L. [Department of Diagnostic Imaging (United States); Warren Alpert Medical School of Brown University (United States); Lifespan Biostatistics Core (United States); Rhode Island Hospital (United States); Monu, Nicholas; Wolf, Farrah; Seidler, Michael [Department of Diagnostic Imaging (United States); Warren Alpert Medical School of Brown University (United States); Rhode Island Hospital (United States); Collins, Scott [Department of Diagnostic Imaging (United States); Rhode Island Hospital (United States); Kim, Jeomsoon [Department of Medical Physics (United States); Rhode Island Hospital (United States); Dupuy, Damian E., E-mail: ddupuy@comcast.net [Department of Diagnostic Imaging (United States); Warren Alpert Medical School of Brown University (United States); Rhode Island Hospital (United States)

    2017-04-15

    Highlights: • This study aimed to determine optimal scanning parameters for commonly-used tumor ablation applicators. • The findings illustrate the overall interaction of the effects of kVp, ASiR, and reconstruction algorithm within and between probes, so that radiologists may easily reference optimal imaging performance. • Optimum combinations for each probe are provided. - Abstract: Purpose: CT-beam hardening artifact can make tumor margin visualization and its relationship to the ablation applicator tip challenging. To determine optimal scanning parameters for commonly-used applicators. Materials and methods: Applicators were placed in ex-vivo cow livers with implanted mock tumors, surrounded by bolus gel. Various CT scans were performed at 440 mA with 5 mm thickness changing kVp, scan time, ASiR, scan type, pitch, and reconstruction algorithm. Four radiologists blindly scored the images for image quality and artifact quantitatively. Results: A significant relationship between probe, kVp level, ASiR level, and reconstruction algorithm was observed concerning both image artifact and image quality (both p = <0.0001). Specifically, there are certain combinations of kVp, ASiR, and reconstruction algorithm that yield better images than other combinations. In particular, one probe performed equivalently or better than any competing probe considered here, regardless of kVp, ASiR, and reconstruction algorithm combination. Conclusion: The findings illustrate the overall interaction of the effects of kVp, ASiR, and reconstruction algorithm within and between probes, so that radiologists may easily reference optimal imaging performance for a certain combinations of kVp, ASiR, reconstruction algorithm and probes at their disposal. Optimum combinations for each probe are provided.

  6. The effect of ethanol infusion on the size of the ablated lesion in radiofrequency thermal ablation: A pilot study

    International Nuclear Information System (INIS)

    Kim, Young Sun; Rhim, Hyun Chul; Koh, Byung Hee; Cho, On Koo; Seo, Heung Suk; Kim, Yong Soo; Joo, Kyoung Bin

    2001-01-01

    To assess the effect of ethanol infusion on the size of ablated lesion during radiofrequency (RF) thermal ablation. We performed an ex vivo experimental study using a total of 15 pig livers. Three groups were designed: 1)normal control (n=10), 2) saline infusion (n=10) 3) ethanol infusion (n=10). Two radiofrequency ablations were done using a 50 watt RF generator and a 15 guage expandable elections with four prongs in each liver. During ablation for 8 minutes, continuous infusion of fluid at a rate of 0.5 ml/min through the side arm of electrode was performed. We checked the frequency of the 'impeded-out' phenomenon due to abrupt increase of impedance during ablation. Size of ablated lesion was measured according to length, width, height, and subsequently volume after the ablations. The sizes of the ablated lesions were compared between the three groups. 'Impeded-out' phenomenon during ablation was noted 4 times in control group, although that never happened in saline or ethanol infusion groups. There were significant differences in the volumes of ablated lesions between control group (10.62 ± 1.45 cm 3 ) and saline infusion group (15.33 ± 2.47 cm 3 ), and saline infusion group and ethanol infusion group (18.78 ± 3.58 cm 3 ) (p<0.05). Fluid infusion during radiofrequency thermal ablation decrease a chance of charming and increase the volume of the ablated lesion. Ethanol infusion during ablation may induce larger volume of ablated lesion than saline infusion.

  7. Non-Fourier based thermal-mechanical tissue damage prediction for thermal ablation.

    Science.gov (United States)

    Li, Xin; Zhong, Yongmin; Smith, Julian; Gu, Chengfan

    2017-01-02

    Prediction of tissue damage under thermal loads plays important role for thermal ablation planning. A new methodology is presented in this paper by combing non-Fourier bio-heat transfer, constitutive elastic mechanics as well as non-rigid motion of dynamics to predict and analyze thermal distribution, thermal-induced mechanical deformation and thermal-mechanical damage of soft tissues under thermal loads. Simulations and comparison analysis demonstrate that the proposed methodology based on the non-Fourier bio-heat transfer can account for the thermal-induced mechanical behaviors of soft tissues and predict tissue thermal damage more accurately than classical Fourier bio-heat transfer based model.

  8. Prognostic factors for the success of thermal balloon ablation in the treatment of menorrhagia

    NARCIS (Netherlands)

    Bongers, M. Y.; Mol, B. W. J.; Brölmann, H. A. M.

    2002-01-01

    OBJECTIVE: To identify predictive factors that will ensure successful menorrhagia treatment using hot fluid balloon endometrial ablation. METHODS: This is a prospective study on patients referred for menorrhagia and treated with hot fluid thermal balloon ablation. Potential prognostic factors for

  9. Effects of Arsenic Trioxide on Radiofrequency Ablation of VX2 Liver Tumor: Intraarterial versus Intravenous Administration

    International Nuclear Information System (INIS)

    Seong, Nak Jong; Yoon, Chang Jin; Kang, Sung Gwon; Chung, Jin Wook; Kim, Hyo Cheol; Park, Jae Hyung

    2012-01-01

    Arsenic trioxide (As 2 O 3 ) can be used as a possible pharmaceutical alternative that augments radiofrequency (RF) ablation by reducing tumor blood flow. The aim of this study was to assess the effect of intraarterial and intravenous administration of As 2 O 3 on RF-induced ablation in an experimentally induced liver tumor. VX2 carcinoma was grown in the livers of 30 rabbits. As 2 O 3 (1 mg/kg) was administered through the hepatic artery (n = 10, group A) or ear vein (n = 10, group B), 30 minutes before RF ablation (125 mA ± 35; 90 ± 5 degrees Celsius). As a control group, 10 rabbits were treated with RF ablation alone (group C). RF was intentionally applied to the peripheral margin of the tumor so that ablation can cover the tumor and adjacent hepatic parenchyma. Ablation areas of the tumor and adjacent parenchymal changes among three groups were compared by the Kruskal-Wallis and Mann-Whitney U test. The overall ablation areas were 156 ± 28.9 mm 2 (group A), 119 ± 31.7 (group B), and 92 ± 17.4 (group C, p 2 ) than both group B (50 ± 19.4, p = 0.02) and group C (28 ± 2.2, p 2 O 3 . The intraarterial administration of As 2 O 3 seems to be helpful for the selective ablation of the tumor.

  10. Massive hematemesis after radiofrequency ablation of metastatic liver tumor with successful hemostasis achieved through transarterial embolization.

    Science.gov (United States)

    Liu, Chien-An; Chiu, Nai-Chi; Chiou, Yi-You

    2018-03-03

    Hemorrhagic complications are the most common major complications that occur after radiofrequency ablation, but hematemesis as a complication after radiofrequency ablation for hepatic tumor has not been mentioned before. A hepatogastric fistula as a delayed complication is also rare. We present the case of a 77-year-old man with severe hematemesis that occurred 2 months after radiofrequency ablation of a liver metastasis of gastric cancer. A ruptured hepatic artery pseudoaneurysm and a hepatogastric fistula were confirmed through serial imaging examinations. The current case is reported in combination with 2 rare major complications after radiofrequency ablation of a liver tumor. Copyright © 2018. Published by Elsevier Inc.

  11. Tumor Volume-Adapted Dosing in Stereotactic Ablative Radiotherapy of Lung Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Trakul, Nicholas; Chang, Christine N.; Harris, Jeremy [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA (United States); Chapman, Christopher [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA (United States); University of Michigan School of Medicine, Ann Arbor, MI (United States); Rao, Aarti [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA (United States); University of California, Davis, School of Medicine, Davis, CA (United States); Shen, John [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA (United States); University of California, Irvine, School of Medicine, Irvine, CA (United States); Quinlan-Davidson, Sean [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA (United States); Department of Radiation Oncology, McMaster University, Juravinski Cancer Centre, Hamilton, Ontario (Canada); Filion, Edith J. [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA (United States); Departement de Medecine, Service de Radio-Oncologie, Centre Hospitalier de l' Universite de Montreal, Montreal, Quebec (Canada); Wakelee, Heather A.; Colevas, A. Dimitrios [Department of Medicine, Division of Oncology, Stanford University School of Medicine, Stanford, CA (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA (United States); Whyte, Richard I. [Department of Cardiothoracic Surgery, Division of General Thoracic Surgery, Stanford University School of Medicine, Stanford, CA (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA (United States); and others

    2012-09-01

    Purpose: Current stereotactic ablative radiotherapy (SABR) protocols for lung tumors prescribe a uniform dose regimen irrespective of tumor size. We report the outcomes of a lung tumor volume-adapted SABR dosing strategy. Methods and Materials: We retrospectively reviewed the outcomes in 111 patients with a total of 138 primary or metastatic lung tumors treated by SABR, including local control, regional control, distant metastasis, overall survival, and treatment toxicity. We also performed subset analysis on 83 patients with 97 tumors treated with a volume-adapted dosing strategy in which small tumors (gross tumor volume <12 mL) received single-fraction regimens with biologically effective doses (BED) <100 Gy (total dose, 18-25 Gy) (Group 1), and larger tumors (gross tumor volume {>=}12 mL) received multifraction regimens with BED {>=}100 Gy (total dose, 50-60 Gy in three to four fractions) (Group 2). Results: The median follow-up time was 13.5 months. Local control for Groups 1 and 2 was 91.4% and 92.5%, respectively (p = 0.24) at 12 months. For primary lung tumors only (excluding metastases), local control was 92.6% and 91.7%, respectively (p = 0.58). Regional control, freedom from distant metastasis, and overall survival did not differ significantly between Groups 1 and 2. Rates of radiation pneumonitis, chest wall toxicity, and esophagitis were low in both groups, but all Grade 3 toxicities developed in Group 2 (p = 0.02). Conclusion: A volume-adapted dosing approach for SABR of lung tumors seems to provide excellent local control for both small- and large-volume tumors and may reduce toxicity.

  12. Tumor Volume-Adapted Dosing in Stereotactic Ablative Radiotherapy of Lung Tumors

    International Nuclear Information System (INIS)

    Trakul, Nicholas; Chang, Christine N.; Harris, Jeremy; Chapman, Christopher; Rao, Aarti; Shen, John; Quinlan-Davidson, Sean; Filion, Edith J.; Wakelee, Heather A.; Colevas, A. Dimitrios; Whyte, Richard I.

    2012-01-01

    Purpose: Current stereotactic ablative radiotherapy (SABR) protocols for lung tumors prescribe a uniform dose regimen irrespective of tumor size. We report the outcomes of a lung tumor volume-adapted SABR dosing strategy. Methods and Materials: We retrospectively reviewed the outcomes in 111 patients with a total of 138 primary or metastatic lung tumors treated by SABR, including local control, regional control, distant metastasis, overall survival, and treatment toxicity. We also performed subset analysis on 83 patients with 97 tumors treated with a volume-adapted dosing strategy in which small tumors (gross tumor volume <12 mL) received single-fraction regimens with biologically effective doses (BED) <100 Gy (total dose, 18–25 Gy) (Group 1), and larger tumors (gross tumor volume ≥12 mL) received multifraction regimens with BED ≥100 Gy (total dose, 50–60 Gy in three to four fractions) (Group 2). Results: The median follow-up time was 13.5 months. Local control for Groups 1 and 2 was 91.4% and 92.5%, respectively (p = 0.24) at 12 months. For primary lung tumors only (excluding metastases), local control was 92.6% and 91.7%, respectively (p = 0.58). Regional control, freedom from distant metastasis, and overall survival did not differ significantly between Groups 1 and 2. Rates of radiation pneumonitis, chest wall toxicity, and esophagitis were low in both groups, but all Grade 3 toxicities developed in Group 2 (p = 0.02). Conclusion: A volume-adapted dosing approach for SABR of lung tumors seems to provide excellent local control for both small- and large-volume tumors and may reduce toxicity.

  13. Cavitation-enhanced MR-guided focused ultrasound ablation of rabbit tumors in vivo using phase shift nanoemulsions

    Science.gov (United States)

    Kopechek, Jonathan A.; Park, Eun-Joo; Zhang, Yong-Zhi; Vykhodtseva, Natalia I.; McDannold, Nathan J.; Porter, Tyrone M.

    2014-07-01

    Advanced tumors are often inoperable due to their size and proximity to critical vascular structures. High intensity focused ultrasound (HIFU) has been developed to non-invasively thermally ablate inoperable solid tumors. However, the clinical feasibility of HIFU ablation therapy has been limited by the long treatment times (on the order of hours) and high acoustic intensities required. Studies have shown that inertial cavitation can enhance HIFU-mediated heating by generating broadband acoustic emissions that increase tissue absorption and accelerate HIFU-induced heating. Unfortunately, initiating inertial cavitation in tumors requires high intensities and can be unpredictable. To address this need, phase-shift nanoemulsions (PSNE) have been developed. PSNE consist of lipid-coated liquid perfluorocarbon droplets that are less than 200 nm in diameter, thereby allowing passive accumulation in tumors through leaky tumor vasculature. PSNE can be vaporized into microbubbles in tumors in order to nucleate cavitation activity and enhance HIFU-mediated heating. In this study, MR-guided HIFU treatments were performed on intramuscular rabbit VX2 tumors in vivo to assess the effect of vaporized PSNE on acoustic cavitation and HIFU-mediated heating. HIFU pulses were delivered for 30 s using a 1.5 MHz, MR-compatible transducer, and cavitation emissions were recorded with a 650 kHz ring hydrophone while temperature was monitored using MR thermometry. Cavitation emissions were significantly higher (P cavitation which correlates with enhanced HIFU-mediated heating in tumors. This suggests that PSNE could potentially be used to reduce the time and/or acoustic intensity required for HIFU-mediated heating, thereby increasing the feasibility and clinical efficacy of HIFU thermal ablation therapy.

  14. Adrenal neoplasms: Effectiveness and safety of CT-guided ablation of 23 tumors in 22 patients

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, Farrah J.; Dupuy, Damian E.; Machan, Jason T. [Department of Diagnostic Imaging and the Office of Research Administration, Alpert Medical School of Brown University, Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States); Mayo-Smith, William W., E-mail: wmayo-smith@lifespan.org [Department of Diagnostic Imaging and the Office of Research Administration, Alpert Medical School of Brown University, Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States)

    2012-08-15

    Purpose: To retrospectively evaluate the effectiveness and safety of image-guided ablation of adrenal tumors. Materials and methods: : This HIPAA-compliant study was IRB approved and informed consent was waived. From 5/1999-6/2008, 20 consecutive adrenal metastases (mean diameter 4.2 cm; range, 2-8) and 3 hormonally active primary adrenal tumors (mean diameter 2.3 cm; range, 1-4), including an aldosteronoma and 2 pheochromocytomas in 22 patients (14 men, 8 women; mean age 61 years; range 40-84) were ablated in 23 sessions. Bilateral metastases were treated in a single patient. Radiofrequency ablation was used to treat 16 adrenal metastases and the 3 hyperfunctioning tumors. Microwave ablation was used to treat 4 metastases. Successful treatment was defined as a lack of both enhancement on follow-up contrast enhanced CT and/or up-take on FDG PET-CT and for functioning tumors, resolution of biochemical abnormalities. Results: Technical success was achieved in all sessions. Mean follow-up was 45.1 months (range, 1-91) Local tumor progression (focal enhancement at ablation site {>=}1 cm in short axis) was detected in 4 of 23 tumors, two of which were identified bilaterally in a single patient prompting re-treatment. Of 19 patients with metastatic disease, 16 had fatal extra-adrenal disease progression, and 3 remain alive. Two of the 3 patients who underwent ablation of hyperfunctioning tumors remain alive, including the patient with an aldosteronoma who had recurrent symptoms 91 months post ablation. Intra-ablative hypertension occurred in 9% (2/23) of sessions and was successfully treated pharmacologically. Conclusion: Ablation of metastatic and hyperfunctioning adrenal tumors is safe and may provide local control and treatment of pathologic biochemical activity.

  15. Adrenal neoplasms: Effectiveness and safety of CT-guided ablation of 23 tumors in 22 patients

    International Nuclear Information System (INIS)

    Wolf, Farrah J.; Dupuy, Damian E.; Machan, Jason T.; Mayo-Smith, William W.

    2012-01-01

    Purpose: To retrospectively evaluate the effectiveness and safety of image-guided ablation of adrenal tumors. Materials and methods: : This HIPAA-compliant study was IRB approved and informed consent was waived. From 5/1999-6/2008, 20 consecutive adrenal metastases (mean diameter 4.2 cm; range, 2–8) and 3 hormonally active primary adrenal tumors (mean diameter 2.3 cm; range, 1–4), including an aldosteronoma and 2 pheochromocytomas in 22 patients (14 men, 8 women; mean age 61 years; range 40–84) were ablated in 23 sessions. Bilateral metastases were treated in a single patient. Radiofrequency ablation was used to treat 16 adrenal metastases and the 3 hyperfunctioning tumors. Microwave ablation was used to treat 4 metastases. Successful treatment was defined as a lack of both enhancement on follow-up contrast enhanced CT and/or up-take on FDG PET-CT and for functioning tumors, resolution of biochemical abnormalities. Results: Technical success was achieved in all sessions. Mean follow-up was 45.1 months (range, 1–91) Local tumor progression (focal enhancement at ablation site ≥1 cm in short axis) was detected in 4 of 23 tumors, two of which were identified bilaterally in a single patient prompting re-treatment. Of 19 patients with metastatic disease, 16 had fatal extra-adrenal disease progression, and 3 remain alive. Two of the 3 patients who underwent ablation of hyperfunctioning tumors remain alive, including the patient with an aldosteronoma who had recurrent symptoms 91 months post ablation. Intra-ablative hypertension occurred in 9% (2/23) of sessions and was successfully treated pharmacologically. Conclusion: Ablation of metastatic and hyperfunctioning adrenal tumors is safe and may provide local control and treatment of pathologic biochemical activity.

  16. Ultrasound elastographic imaging of thermal lesions and temperature profiles during radiofrequency ablation

    Science.gov (United States)

    Techavipoo, Udomchai

    Manual palpation to sense variations in tissue stiffness for disease diagnosis has been regularly performed by clinicians for centuries. However, it is generally limited to large and superficial structures and the ability of the physician performing the palpation. Imaging of tissue stiffness or elastic properties via the aid of modern imaging such as ultrasound and magnetic resonance imaging, referred to as elastography, enhances the capability for disease diagnosis. In addition, elastography could be used for monitoring tissue response to minimally invasive ablative therapies, which are performed percutaneously to destruct tumors with minimum damage to surrounding tissue. Monitoring tissue temperature during ablation is another approach to estimate tissue damage. The ultimate goal of this dissertation is to improve the image quality of elastograms and temperature profiles for visualizing thermal lesions during and after ablative therapies. Elastographic imaging of thermal lesions is evaluated by comparison of sizes, shapes, and volumes with the results obtained using gross pathology. Semiautomated segmentation of lesion boundaries on elastograms is also developed. It provides comparable results to those with manual segmentation. Elastograms imaged during radiofrequency ablation in vitro show that the impact of gas bubbles during ablation on the ability to delineate the thermal lesion is small. Two novel methods to reduce noise artifacts in elastograms, and an accurate estimation of displacement vectors are proposed. The first method applies wavelet-denoising algorithms to the displacement estimates. The second method utilizes angular compounding of the elastograms generated using ultrasound signal frames acquired from different insonification angles. These angular frames are also utilized to estimate all tissue displacement vector components in response to a deformation. These enable the generation of normal and shear strain elastograms and Poisson's ratio

  17. Percutaneous radiofrequency and microwave ablation in the treatment of renal tumors - 10 years of experience.

    Science.gov (United States)

    Dvorak, Petr; Hoffmann, Petr; Brodak, Milos; Kosina, Josef; Pacovsky, Jaroslav; Raupach, Jan; Krajina, Antonin

    2017-12-01

    The standard radical treatment of renal cell carcinoma is surgical resection, but it is not suitable for patients with serious medical comorbidities and solitary kidney tumors. Minimally invasive ablation techniques could be an appropriate therapeutic alternative. To retrospectively evaluate the technical success, mid-term and long-term efficacy and safety of radiofrequency and microwave ablation in patients with small renal tumors. Over the course of 10 years, 91 ablation procedures in 64 patients for 68 tumors, of size 12-60 mm, were performed using only conscious sedation. These ablations were done under the guidance of computed tomography. We treated 41 males and 23 females with solitary kidney tumors (14 cases) and tumors in non-surgical candidates (54 cases). In 50 (73.5%) tumors single treatment was successful; in 13 (19.1%) cases a second procedure was used successfully, and in the 5 largest tumors (sizes 45-60 mm, 7.4%) a third treatment was necessary. Within the follow-up 10 (15.6%) patients died, but none due to metastatic renal cell carcinoma. Only 1 serious complication was observed - retroperitoneal and psoatic hematoma. Early recurrence occurred in 18 (26.5%) tumors. Late recurrence was detected in 5 (7.4%) cases. In all cases complete local control of the renal tumors was reached. Percutaneous ablation is a very effective treatment for patients with small renal tumors of the T1a group with a minimal complication rate.

  18. Percutaneous thermal ablation for stage IA non-small cell lung cancer: long-term follow-up.

    Science.gov (United States)

    Narsule, Chaitan K; Sridhar, Praveen; Nair, Divya; Gupta, Avneesh; Oommen, Roy G; Ebright, Michael I; Litle, Virginia R; Fernando, Hiran C

    2017-10-01

    Surgical resection is the most effective curative therapy for non-small cell lung cancer (NSCLC). However, many patients are unable to tolerate resection secondary to poor reserve or comorbid disease. Radiofrequency ablation (RFA) and microwave ablation (MWA) are methods of percutaneous thermal ablation that can be used to treat medically inoperable patients with NSCLC. We present long-term outcomes following thermal ablation of stage IA NSCLC from a single center. Patients with stage IA NSCLC and factors precluding resection who underwent RFA or MWA from July 2005 to September 2009 were studied. CT and PET-CT scans were performed at 3 and 6 month intervals, respectively, for first 24 months of follow-up. Factors associated with local progression (LP) and overall survival (OS) were analyzed. Twenty-one patients underwent 21 RFA and 4 MWA for a total of 25 ablations. Fifteen patients had T1a and six patients had T1b tumors. Mean follow-up was 42 months, median survival was 39 months, and OS at three years was 52%. There was no significant difference in median survival between T1a nodules and T1b nodules (36 vs . 39 months, P=0.29) or for RFA and MWA (36 vs . 50 months, P=0.80). Ten patients had LP (47.6%), at a median time of 35 months. There was no significant difference in LP between T1a and T1b tumors (22 vs . 35 months, P=0.94) or RFA and MWA (35 vs . 17 months, P=0.18). Median OS with LP was 32 months compared to 39 months without LP (P=0.68). Three patients underwent repeat ablations. Mean time to LP following repeat ablation was 14.75 months. One patient had two repeat ablations and was disease free at 40-month follow-up. Thermal ablation effectively treated or controlled stage IA NSCLC in medically inoperable patients. Three-year OS exceeded 50%, and LP did not affect OS. Therefore, thermal ablation is a viable option for medically inoperable patients with early stage NSCLC.

  19. Effect of variable heat transfer coefficient on tissue temperature next to a large vessel during radiofrequency tumor ablation

    Directory of Open Access Journals (Sweden)

    Pinheiro Cleber

    2008-07-01

    Full Text Available Abstract Background One of the current shortcomings of radiofrequency (RF tumor ablation is its limited performance in regions close to large blood vessels, resulting in high recurrence rates at these locations. Computer models have been used to determine tissue temperatures during tumor ablation procedures. To simulate large vessels, either constant wall temperature or constant convective heat transfer coefficient (h have been assumed at the vessel surface to simulate convection. However, the actual distribution of the temperature on the vessel wall is non-uniform and time-varying, and this feature makes the convective coefficient variable. Methods This paper presents a realistic time-varying model in which h is a function of the temperature distribution at the vessel wall. The finite-element method (FEM was employed in order to model RF hepatic ablation. Two geometrical configurations were investigated. The RF electrode was placed at distances of 1 and 5 mm from a large vessel (10 mm diameter. Results When the ablation procedure takes longer than 1–2 min, the attained coagulation zone obtained with both time-varying h and constant h does not differ significantly. However, for short duration ablation (5–10 s and when the electrode is 1 mm away from the vessel, the use of constant h can lead to errors as high as 20% in the estimation of the coagulation zone. Conclusion For tumor ablation procedures typically lasting at least 5 min, this study shows that modeling the heat sink effect of large vessels by applying constant h as a boundary condition will yield precise results while reducing computational complexity. However, for other thermal therapies with shorter treatment using a time-varying h may be necessary.

  20. Meta-analysis of bipolar radiofrequency endometrial ablation versus thermal balloon endometrial ablation for the treatment of heavy menstrual bleeding.

    Science.gov (United States)

    Zhai, Yan; Zhang, Zihan; Wang, Wei; Zheng, Tingping; Zhang, Huili

    2018-01-01

    Heavy menstrual bleeding is a common problem that can severely affect quality of life. To compare bipolar radiofrequency endometrial ablation and thermal balloon ablation for heavy menstrual bleeding in terms of efficacy and health-related quality of life (HRQoL). Online registries were systematically searched using relevant terms without language restriction from inception to November 24, 2016. Randomized control trials or cohort studies of women with heavy menstrual bleeding comparing the efficacy of two treatments were eligible. Data were extracted. Results were expressed as risk ratios (RRs) or weighted mean differences (WMDs) with 95% confidence intervals (CIs). Six studies involving 901 patients were included. Amenorrhea rate at 12 months was significantly higher after bipolar radiofrequency endometrial ablation than after thermal balloon ablation (RR 2.73, 95% CI 2.00-3.73). However, no difference at 12 months was noted for dysmenorrhea (RR 1.04, 95% CI 0.68-1.58) or treatment failure (RR 0.78, 95% CI 0.38-1.60). The only significant difference for HRQoL outcomes was for change in SAQ pleasure score (12 months: WMD -3.51, 95% CI -5.42 to -1.60). Bipolar radiofrequency endometrial ablation and thermal balloon ablation reduce menstrual loss and improve quality of life. However, bipolar radiofrequency endometrial ablation is more effective in terms of amenorrhea rate and SAQ pleasure. © 2017 International Federation of Gynecology and Obstetrics.

  1. Measurement of ventilation- and perfusion-mediated cooling during laser ablation in ex vivo human lung tumors

    Energy Technology Data Exchange (ETDEWEB)

    Vietze, Andrea, E-mail: anvie@gmx.de [Department of Diagnostic Radiology and Neuroradiology, Ernst-Moritz-Arndt-Universitaet Greifswald, Sauerbruchstrasse, 17487 Greifswald (Germany); Koch, Franziska, E-mail: franzi_koch@hotmail.com [Department of Diagnostic Radiology and Neuroradiology, Ernst-Moritz-Arndt-Universitaet Greifswald, Sauerbruchstrasse, 17487 Greifswald (Germany); Laskowski, Ulrich, E-mail: ulrich.laskowski@klinikum-luedenscheid.de [Department of Vascular and Thoracic Surgery, Klinikum Luedenscheid, Paulmannshoeher Strasse 14, 58515 Luedenscheid (Germany); Linder, Albert, E-mail: albert.linder@klinikum-bremen-ost.de [Department of Thoracic Surgery, Klinikum Bremen-Ost, Zuericher Strasse 40, 28325 Bremen (Germany); Hosten, Norbert, E-mail: hosten@uni-greifswald.de [Department of Diagnostic Radiology and Neuroradiology, Ernst-Moritz-Arndt-Universitaet Greifswald, Sauerbruchstrasse, 17487 Greifswald (Germany)

    2011-11-15

    Purpose: Perfusion-mediated tissue cooling has often been described in the literature for thermal ablation therapies of liver tumors. The objective of this study was to investigate the cooling effects of both perfusion and ventilation during laser ablation of lung malignancies. Materials and methods: An ex vivo lung model was used to maintain near physiological conditions for the specimens. Fourteen human lung lobes containing only primary lung tumors (non-small cell lung cancer) were used. Laser ablation was carried out using a Nd:YAG laser with a wavelength of 1064 nm and laser fibers with 30 mm diffusing tips. Continuous invasive temperature measurement in 10 mm distance from the laser fiber was performed. Laser power was increased at 2 W increments starting at 10 W up to a maximum power of 12-20 W until a temperature plateau around 60 deg. C was reached at one sensor. Ventilation and perfusion were discontinued for 6 min each to assess their effects on temperature development. Results: The experiments lead to 25 usable temperature profiles. A significant temperature increase was observed for both discontinued ventilation and perfusion. In 6 min without perfusion, the temperature rose about 5.5 deg. C (mean value, P < 0.05); without ventilation it increased about 7.0 deg. C (mean value, P < 0.05). Conclusion: Ventilation- and perfusion-mediated tissue cooling are significant influencing factors on temperature development during thermal ablation. They should be taken into account during the planning and preparation of minimally invasive lung tumor treatment in order to achieve complete ablation.

  2. Radiofrequency ablation of liver tumors by using monopolar perfusion electrode:an analysis of therapeutic results

    International Nuclear Information System (INIS)

    Luo Rongguang; Gu Yangkui; Gao Fei; Zhang Liang; Zhao Ming; Fan Weijun; Wu Peihong; Huang Jinhua

    2010-01-01

    Objective: To investigate the clinical value of CT-guided radiofrequency ablation by using monopolar perfusion electrode in treating liver tumors. Methods: From January 2008 to December 2008, 24 patients with 37 lesions of liver tumors were treated with radiofrequency ablation by using monopolar perfusion electrode (RITA UniBlate). Of the 24 patients,solitary lesion was seen in 14, two lesions in 7 and three lesions in 3. Among 37 lesions,the maximum diameter of the lesion ≤ 3 cm, 3.1∼5 cm and > 5 cm was determined in 24, 8 and 5, respectively. The changes of the tumor size and the AFP level were observed. A follow-up lasting for 12 months was conducted. Results: After radiofrequency ablation twenty-two lesions (22/37, 59.5%) were completely ablated, of which nineteen tumors (19/24, 79.2%) were smaller than 3 cm in diameter, two tumors (2 / 8, 25%) had a diameter between 3.1 cm and 5 cm, one tumor (1 / 5, 20%) was larger than 5 cm. Fifteen tumors (15 / 37, 40.5%) were not completely ablated. During the follow-up period of 12 months, fifteen patients (15 / 24, 62.5%) remained alive and nine patients died, of whom the survival time was less than 6 months in six and was 6 -12 months in 4. After radiofrequency ablation, the AFP level decreased to normal level in 5 patients (5 / 10, 50%), and mild decrease of AFP, but still higher than normal,was seen in 3 patients (3 / 10, 30%). Of 10 patients who had a positive AFP test, 2 (2 / 10, 10%) showed a continuous rise in the AFP level. After radiofrequency ablation, one patient developed a minor hepatic subcapsular bleeding,and all patients complained of different degrees of fever and upper abdominal pain. Conclusion: CT-guided radiofrequency ablation by using monopolar perfusion electrode is a minimally-invasive technique with reliable short-term results and fewer complications. Therefore, it is a safe and effective local treatment for liver cancer. For tumors smaller than 3 cm in diameter complete ablation can be

  3. Real-time tumor ablation simulation based on the dynamic mode decomposition method

    KAUST Repository

    Bourantas, George C.; Ghommem, Mehdi; Kagadis, George C.; Katsanos, Konstantinos H.; Loukopoulos, Vassilios C.; Burganos, Vasilis N.; Nikiforidis, George C.

    2014-01-01

    Purpose: The dynamic mode decomposition (DMD) method is used to provide a reliable forecasting of tumor ablation treatment simulation in real time, which is quite needed in medical practice. To achieve this, an extended Pennes bioheat model must

  4. Thermal ablation for partial splenectomy hemostasis, spleen trauma, splenic metastasis and hypersplenism.

    Science.gov (United States)

    Duan, Ya-Qi; Liang, Ping

    2013-05-01

    Many studies have been conducted on splenic thermal ablation for partial splenectomy hemostasis, spleen trauma, splenic metastasis and hypersplenism. In this article, we review the evolution and current status of radiofrequency and microwave ablation in the treatment of spleen diseases. All publications from 1990 to 2011 on radiofrequency and microwave ablation for partial splenectomy hemostasis, spleen trauma, splenic metastasis and hypersplenism were retrieved by searching PubMed. Thermal ablation in the spleen for partial splenectomy hemostasis, spleen trauma, splenic metastasis and hypersplenism can preserve part of the spleen and maintain splenic immunologic function. Thermal ablation for assisting hemostasis in partial splenectomy minimizes blood loss during operation. Thermal ablation for spleen trauma reduces the number of splenectomy and the amount of blood transfusion. Thermal ablation for splenic metastasis is minimally invasive and can be done under the guidance of an ultrasound, which helps shorten the recovery time. Thermal ablation for hypersplenism increases platelet (PLT) and white blood cell (WBC) counts and improves liver function. It also helps to maintain splenic immunologic function and even improves splenic immunologic function in the short-term. In conclusion, thermal ablative approaches are promising for partial splenectomy hemostasis, spleen trauma, splenic metastasis and hypersplenism. In order to improve therapeutic effects, directions for future studies may include standardized therapeutic indications, prolonged observation periods and enlarged sample sizes.

  5. Laparoscopic microwave thermosphere ablation of malignant liver tumors: An analysis of 53 cases.

    Science.gov (United States)

    Zaidi, Nisar; Okoh, Alexis; Yigitbas, Hakan; Yazici, Pinar; Ali, Noaman; Berber, Eren

    2016-02-01

    Microwave thermosphere ablation (MTA) is a new technology that is designed to create spherical zones of ablation using a single antenna. The aim of this study is to assess the results of MTA in a large series of patients. This was a prospective study assessing the use of MTA in patients with malignant liver tumors. The procedures were done mostly laparoscopically and ablation zones created were assessed for completeness of tumor response, spherical geometry and recurrence on tri-phasic CT scans done on follow-up. There were a total of 53 patients with an average of 3 tumors measuring 1.5 cm. Ablations were performed laparoscopically in all but eight patients. Morbidity was 11.3% (n = 6), and mortality zero. On postoperative scans, there was 99.3% tumor destruction. Roundness indices A, B, and transverse were 1.1, 1.0, and 0.9, respectively. At a median follow-up of 4.5 months, incomplete ablation was seen in 1 of 149 lesions treated (0.7%) and local tumor recurrence in 1 lesion (0.7%). The results of this series confirm the safety and feasibility of MTA technology. The 99.3% rate of complete tumor ablation and low rate of local recurrence at short-term follow up are promising. © 2015 Wiley Periodicals, Inc.

  6. Effects of Arsenic Trioxide on Radiofrequency Ablation of VX2 Liver Tumor: Intraarterial versus Intravenous Administration

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Nak Jong; Yoon, Chang Jin; Kang, Sung Gwon [Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Chung, Jin Wook; Kim, Hyo Cheol; Park, Jae Hyung [Seoul National University Hospital, Seoul (Korea, Republic of)

    2012-03-15

    Arsenic trioxide (As{sub 2}O{sub 3}) can be used as a possible pharmaceutical alternative that augments radiofrequency (RF) ablation by reducing tumor blood flow. The aim of this study was to assess the effect of intraarterial and intravenous administration of As{sub 2}O{sub 3} on RF-induced ablation in an experimentally induced liver tumor. VX2 carcinoma was grown in the livers of 30 rabbits. As{sub 2}O{sub 3} (1 mg/kg) was administered through the hepatic artery (n = 10, group A) or ear vein (n = 10, group B), 30 minutes before RF ablation (125 mA {+-} 35; 90 {+-} 5 degrees Celsius). As a control group, 10 rabbits were treated with RF ablation alone (group C). RF was intentionally applied to the peripheral margin of the tumor so that ablation can cover the tumor and adjacent hepatic parenchyma. Ablation areas of the tumor and adjacent parenchymal changes among three groups were compared by the Kruskal-Wallis and Mann-Whitney U test. The overall ablation areas were 156 {+-} 28.9 mm{sup 2} (group A), 119 {+-} 31.7 (group B), and 92 {+-} 17.4 (group C, p < 0.04). The ablation area of the tumor was significantly larger in group A (73 {+-} 19.7 mm{sup 2}) than both group B (50 {+-} 19.4, p = 0.02) and group C (28 {+-} 2.2, p < 0.01). The ratios of the tumoral ablation area to the overall ablation area were larger in group A (47 {+-} 10.5%) than that of the other groups (42 {+-} 7.3% in group B and 32 {+-} 5.6% in group C) (p < 0.03). Radiofrequency-induced ablation area can be increased with intraarterial or intravenous administration of As{sub 2}O{sub 3}. The intraarterial administration of As{sub 2}O{sub 3} seems to be helpful for the selective ablation of the tumor.

  7. High-frequency irreversible electroporation (H-FIRE for non-thermal ablation without muscle contraction

    Directory of Open Access Journals (Sweden)

    Arena Christopher B

    2011-11-01

    Full Text Available Abstract Background Therapeutic irreversible electroporation (IRE is an emerging technology for the non-thermal ablation of tumors. The technique involves delivering a series of unipolar electric pulses to permanently destabilize the plasma membrane of cancer cells through an increase in transmembrane potential, which leads to the development of a tissue lesion. Clinically, IRE requires the administration of paralytic agents to prevent muscle contractions during treatment that are associated with the delivery of electric pulses. This study shows that by applying high-frequency, bipolar bursts, muscle contractions can be eliminated during IRE without compromising the non-thermal mechanism of cell death. Methods A combination of analytical, numerical, and experimental techniques were performed to investigate high-frequency irreversible electroporation (H-FIRE. A theoretical model for determining transmembrane potential in response to arbitrary electric fields was used to identify optimal burst frequencies and amplitudes for in vivo treatments. A finite element model for predicting thermal damage based on the electric field distribution was used to design non-thermal protocols for in vivo experiments. H-FIRE was applied to the brain of rats, and muscle contractions were quantified via accelerometers placed at the cervicothoracic junction. MRI and histological evaluation was performed post-operatively to assess ablation. Results No visual or tactile evidence of muscle contraction was seen during H-FIRE at 250 kHz or 500 kHz, while all IRE protocols resulted in detectable muscle contractions at the cervicothoracic junction. H-FIRE produced ablative lesions in brain tissue that were characteristic in cellular morphology of non-thermal IRE treatments. Specifically, there was complete uniformity of tissue death within targeted areas, and a sharp transition zone was present between lesioned and normal brain. Conclusions H-FIRE is a feasible technique for

  8. Fiber-Optic Temperature and Pressure Sensors Applied to Radiofrequency Thermal Ablation in Liver Phantom: Methodology and Experimental Measurements

    Directory of Open Access Journals (Sweden)

    Daniele Tosi

    2015-01-01

    Full Text Available Radiofrequency thermal ablation (RFA is a procedure aimed at interventional cancer care and is applied to the treatment of small- and midsize tumors in lung, kidney, liver, and other tissues. RFA generates a selective high-temperature field in the tissue; temperature values and their persistency are directly related to the mortality rate of tumor cells. Temperature measurement in up to 3–5 points, using electrical thermocouples, belongs to the present clinical practice of RFA and is the foundation of a physical model of the ablation process. Fiber-optic sensors allow extending the detection of biophysical parameters to a vast plurality of sensing points, using miniature and noninvasive technologies that do not alter the RFA pattern. This work addresses the methodology for optical measurement of temperature distribution and pressure using four different fiber-optic technologies: fiber Bragg gratings (FBGs, linearly chirped FBGs (LCFBGs, Rayleigh scattering-based distributed temperature system (DTS, and extrinsic Fabry-Perot interferometry (EFPI. For each instrument, methodology for ex vivo sensing, as well as experimental results, is reported, leading to the application of fiber-optic technologies in vivo. The possibility of using a fiber-optic sensor network, in conjunction with a suitable ablation device, can enable smart ablation procedure whereas ablation parameters are dynamically changed.

  9. Local recurrence after microwave thermosphere ablation of malignant liver tumors: results of a surgical series.

    Science.gov (United States)

    Takahashi, Hideo; Kahramangil, Bora; Berber, Eren

    2018-04-01

    Microwave thermosphere ablation is a new treatment modality that creates spherical ablation zones using a single antenna. This study aims to analyze local recurrence associated with this new treatment modality in patients with malignant liver tumors. This is a prospective clinical study of patients who underwent microwave thermosphere ablation of malignant liver tumors between September 2014 and March 2017. Clinical, operative, and oncologic parameters were analyzed using Kaplan-Meier survival and Cox proportional hazards model. One hundred patients underwent 301 ablations. Ablations were performed laparoscopically in 87 and open in 13 patients. Pathology included neuroendocrine liver metastasis (n = 115), colorectal liver metastasis (n = 100), hepatocellular cancer (n = 21), and other tumor types (n = 65). Ninety-day morbidity was 7% with one not procedure-related mortality. Median follow-up was 16 months with 65% of patients completing at least 12 months of follow-up. The rate of local tumor recurrence rate per lesion was 6.6% (20/301). Local tumor, new hepatic, and extrahepatic recurrences were detected in 15%, 40%, and 40% of patients, respectively. Local recurrence rate per pathology was 12% for both colorectal liver metastasis (12/100) and other metastatic tumors (8/65). No local recurrence was observed to date in the neuroendocrine liver metastasis and in the limited number of patients with hepatocellular cancers. Tumor size >3 cm and tumor type were independent predictors of local recurrence. This is the first study to analyze local recurrence after microwave thermosphere ablation of malignant liver tumors. Short-term local tumor control rate compares favorably with that reported for radiofrequency and other microwave technologies in the literature. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Prognostic value of preoperative absolute lymphocyte count in recurrent hepatocellular carcinoma following thermal ablation: a retrospective analysis

    Directory of Open Access Journals (Sweden)

    Li X

    2014-10-01

    Full Text Available Xin Li, Zhiyu Han, Zhigang Cheng, Jie Yu, Xiaoling Yu, Ping Liang Department of Interventional Ultrasound, Chinese PLA General Hospital, Beijing, People's Republic of China Purpose: To investigate the prognostic value of preoperative absolute lymphocyte count (ALC in recurrent hepatocellular carcinoma (RHCC following thermal ablation. Materials and methods: We retrospectively analyzed the relationship between preoperative ALC and the clinicopathologic factors and long-term prognosis in 423 RHCC patients who underwent curative thermal ablation. Correlation analysis, receiver operating characteristic (ROC calculation, Kaplan–Meier curves, and multivariate regression were used for statistical analysis. Results: The median time to recurrence was 12 months for RHCC patients after thermal ablation. On multivariate Cox regression analysis, preoperative ALC was an independent risk factor for cancer recurrence, along with tumor differentiation and α-fetoprotein level. ALC ≥1.64×109/L defined by ROC calculation was associated with prolonged survival (area under the curve 0.741, P<0.001. Patients with ALC ≥1.64×109/L showed a mean survival of 20.2 months versus 11.6 months for patients with ALC <1.64×109/L (P<0.001. Patients were stratified into high and low groups according to ALC status. After excluding the basic parameters between groups, the 1- and 3-year recurrence rates in the high group were 20.9% and 29.5%, respectively, which were significantly lower than those of the low group (58.4% and 71.9%, respectively; P<0.001. The recurrence-free survival rates in the two groups analyzed by Kaplan–Meier curves were significantly different (P<0.001. Conclusion: Preoperative ALC is a powerful prognostic factor for RHCC recurrence after thermal ablation, which suggests that maintaining a high ALC in RHCC patients might improve cancer outcomes. Keywords: absolute lymphocyte count, recurrent hepatocellular carcinoma, thermal ablation, recurrence  

  11. Exploiting Microwave Imaging Methods for Real-Time Monitoring of Thermal Ablation

    Directory of Open Access Journals (Sweden)

    Rosa Scapaticci

    2017-01-01

    Full Text Available Microwave thermal ablation is a cancer treatment that exploits local heating caused by a microwave electromagnetic field to induce coagulative necrosis of tumor cells. Recently, such a technique has significantly progressed in the clinical practice. However, its effectiveness would dramatically improve if paired with a noninvasive system for the real-time monitoring of the evolving dimension and shape of the thermally ablated area. In this respect, microwave imaging can be a potential candidate to monitor the overall treatment evolution in a noninvasive way, as it takes direct advantage from the dependence of the electromagnetic properties of biological tissues from temperature. This paper explores such a possibility by presenting a proof of concept validation based on accurate simulated imaging experiments, run with respect to a scenario that mimics an ex vivo experimental setup. In particular, two model-based inversion algorithms are exploited to tackle the imaging task. These methods provide independent results in real-time and their integration improves the quality of the overall tracking of the variations occurring in the target and surrounding regions.

  12. Careful treatment planning enables safe ablation of liver tumors adjacent to major blood vessels by percutaneous irreversible electroporation (IRE).

    Science.gov (United States)

    Kos, Bor; Voigt, Peter; Miklavcic, Damijan; Moche, Michael

    2015-09-01

    Irreversible electroporation (IRE) is a tissue ablation method, which relies on the phenomenon of electroporation. When cells are exposed to a sufficiently electric field, the plasma membrane is disrupted and cells undergo an apoptotic or necrotic cell death. Although heating effects are known IRE is considered as non-thermal ablation technique and is currently applied to treat tumors in locations where thermal ablation techniques are contraindicated. The manufacturer of the only commercially available pulse generator for IRE recommends a voltage-to-distance ratio of 1500 to 1700 V/cm for treating tumors in the liver. However, major blood vessels can influence the electric field distribution. We present a method for treatment planning of IRE which takes the influence of blood vessels on the electric field into account; this is illustrated on a treatment of 48-year-old patient with a metastasis near the remaining hepatic vein after a right side hemi-hepatectomy. Output of the numerical treatment planning method shows that a 19.9 cm3 irreversible electroporation lesion was generated and the whole tumor was covered with at least 900 V/cm. This compares well with the volume of the hypodense lesion seen in contrast enhanced CT images taken after the IRE treatment. A significant temperature raise occurs near the electrodes. However, the hepatic vein remains open after the treatment without evidence of tumor recurrence after 6 months. Treatment planning using accurate computer models was recognized as important for electrochemotherapy and irreversible electroporation. An important finding of this study was, that the surface of the electrodes heat up significantly. Therefore the clinical user should generally avoid placing the electrodes less than 4 mm away from risk structures when following recommendations of the manufacturer.

  13. Efficient and controllable thermal ablation induced by short-pulsed HIFU sequence assisted with perfluorohexane nanodroplets.

    Science.gov (United States)

    Chang, Nan; Lu, Shukuan; Qin, Dui; Xu, Tianqi; Han, Meng; Wang, Supin; Wan, Mingxi

    2018-07-01

    A HIFU sequence with extremely short pulse duration and high pulse repetition frequency can achieve thermal ablation at a low acoustic power using inertial cavitation. Because of its cavitation-dependent property, the therapeutic outcome is unreliable when the treatment zone lacks cavitation nuclei. To overcome this intrinsic limitation, we introduced perfluorocarbon nanodroplets as extra cavitation nuclei into short-pulsed HIFU-mediated thermal ablation. Two types of nanodroplets were used with perfluorohexane (PFH) as the core material coated with bovine serum albumin (BSA) or an anionic fluorosurfactant (FS) to demonstrate the feasibility of this study. The thermal ablation process was recorded by high-speed photography. The inertial cavitation activity during the ablation was revealed by sonoluminescence (SL). The high-speed photography results show that the thermal ablation volume increased by ∼643% and 596% with BSA-PFH and FS-PFH, respectively, than the short-pulsed HIFU alone at an acoustic power of 19.5 W. Using nanodroplets, much larger ablation volumes were created even at a much lower acoustic power. Meanwhile, the treatment time for ablating a desired volume significantly reduced in the presence of nanodroplets. Moreover, by adjusting the treatment time, lesion migration towards the HIFU transducer could also be avoided. The SL results show that the thermal lesion shape was significantly dependent on the inertial cavitation in this short-pulsed HIFU-mediated thermal ablation. The inertial cavitation activity became more predictable by using nanodroplets. Therefore, the introduction of PFH nanodroplets as extra cavitation nuclei made the short-pulsed HIFU thermal ablation more efficient by increasing the ablation volume and speed, and more controllable by reducing the acoustic power and preventing lesion migration. Copyright © 2018. Published by Elsevier B.V.

  14. An experimental study of simultaneous ablation with dual probes in radiofrequency thermal ablation

    International Nuclear Information System (INIS)

    Jang, Il Soo; Rhim, Hyun Chul; Koh, Byung Hee; Cho, On Koo; Seo, Heung Suk; Kim, Yong Soo; Kim, Young Sun; Heo, Jeong Nam

    2003-01-01

    To determine the differences between sequential ablation with a single probe and simultaneous ablation with dual probes. Using two 14-gauge expandable probes (nine internal prongs with 4-cm deployment), radiofrequency was applied sequentially (n=8) or simultaneously (n=8) to ten ex-vivo cow livers. Before starting ablation, two RF probes with an inter-probe space of 2 cm (n=8) or 3 cm (n=8) were inserted. In the sequential group, switching the connecting cable to an RF generator permitted ablation with the second probe just after ablation with the first probe had finished. In the simultaneous group, single ablation was performed only after connecting the shafts of both RF probes using a connection device. Each ablation lasted 7 minutes at a target temperature of 105-110 .deg. C. The size and shape of the ablated area, and total ablation time were then compared between the two groups. With 2-cm spacing, the group, mean length and overlapping width of ablated lesions were, respectively, 5.20 and 5.05 cm in the sequential group (n=4), and 5.81 and 5.65 cm in the simultaneous group (n=4). With 3-cm spacing, the corresponding figures were 4.99 and 5.60 cm in the sequential group (n=4), and 6.04 and 6.78 cm in the simultaneous group (n=4). With 2-cm spacing, the mean depth of the proximal waist was 0.58 cm in the sequential (group and 0.28 cm in the simultaneous group, while with 3-cm spacing, the corresponding figures were 1.65 and 1.48 cm. In neither group was there a distal waist. Mean total ablation time was 23.4 minutes in the sequential group and 14 minutes in the simultaneous group. In terms of ablation size and ablation time, simultaneous radiofrequency ablation with dual probes is superior to sequential ablation with a single probe. A simultaneous approach will enable an operator to overcome difficulty in probe repositioning during overlapping ablation, resulting in complete ablation with a successful safety margin

  15. Cavitation-enhanced MR-guided focused ultrasound ablation of rabbit tumors in vivo using phase shift nanoemulsions

    International Nuclear Information System (INIS)

    Kopechek, Jonathan A; Porter, Tyrone M; Park, Eun-Joo; Zhang, Yong-Zhi; Vykhodtseva, Natalia I; McDannold, Nathan J

    2014-01-01

    Advanced tumors are often inoperable due to their size and proximity to critical vascular structures. High intensity focused ultrasound (HIFU) has been developed to non-invasively thermally ablate inoperable solid tumors. However, the clinical feasibility of HIFU ablation therapy has been limited by the long treatment times (on the order of hours) and high acoustic intensities required. Studies have shown that inertial cavitation can enhance HIFU-mediated heating by generating broadband acoustic emissions that increase tissue absorption and accelerate HIFU-induced heating. Unfortunately, initiating inertial cavitation in tumors requires high intensities and can be unpredictable. To address this need, phase-shift nanoemulsions (PSNE) have been developed. PSNE consist of lipid-coated liquid perfluorocarbon droplets that are less than 200 nm in diameter, thereby allowing passive accumulation in tumors through leaky tumor vasculature. PSNE can be vaporized into microbubbles in tumors in order to nucleate cavitation activity and enhance HIFU-mediated heating. In this study, MR-guided HIFU treatments were performed on intramuscular rabbit VX2 tumors in vivo to assess the effect of vaporized PSNE on acoustic cavitation and HIFU-mediated heating. HIFU pulses were delivered for 30 s using a 1.5 MHz, MR-compatible transducer, and cavitation emissions were recorded with a 650 kHz ring hydrophone while temperature was monitored using MR thermometry. Cavitation emissions were significantly higher (P < 0.05) after PSNE injection and this was well correlated with enhanced HIFU-mediated heating in tumors. The peak temperature rise induced by sonication was significantly higher (P < 0.05) after PSNE injection. For example, the mean per cent change in temperature achieved at 5.2 W of acoustic power was 46 ± 22% with PSNE injection. The results indicate that PSNE nucleates cavitation which correlates with enhanced HIFU-mediated heating in tumors. This suggests that PSNE could

  16. Analysis of factors affecting local tumor progression of colorectal cancer liver metastasis after radiofrequency ablation

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Seong Hee; Cho, Yun Ku; Choi, Seung A; Kim, Mi Young; Lee, Ho Suk [Veterans Health Service Medical Center, Seoul (Korea, Republic of)

    2017-03-15

    The purpose of this study was to evaluate the independent predictive factors for local tumor progression (LTP) of colorectal liver metastasis (CRLM) after radiofrequency ablation (RFA). Patients with CRLM were included in the analysis if nodules were up to five in number, each nodule was ≤ 5 cm, and RFA was performed in our center from January 2006 to December 2015. Univariate and multivariate analyses to identify the predictors of LTP were performed by using a Cox proportional hazard model. Overall, 58 tumors from 38 patients were included in this study. LTP occurred in 14 tumors from 9 patients. The overall 1- and 3-year LTP rates were 23.5% and 29.4%, respectively. Multivariate analysis showed that tumor size > 2 cm and insufficient ablative margin were two independently significant adverse prognostic factors for LTP (p = 0.045 and 0.022, respectively). The 3-year LTP rates for 33 and 25 tumors with and without sufficient ablative margin were 4.5% and 61.2%, respectively. The difference was statistically significant (p < 0.001). The difference in the 3-year LTP rates according to the tumor size was not statistically significant (p = 0.791). Insufficient ablative margin seems to be the most potent predictor of LTP after RFA of CRLM.

  17. Percutaneous ultrasound-guided radiofrequency ablation for kidney tumors in patients with surgical risk

    International Nuclear Information System (INIS)

    Salagierski, Marek; Salagierski, Maciej; Sosnowski, Marek; Salagierska-Barwinska, Anna

    2006-01-01

    The aim of this study was to describe our experience with percutaneous ultrasound-guided radiofrequency ablation of kidney tumors. From July 2002 to August 2005, 45 radiofrequency ablations (RFA) in 42 selected patients with kidney tumor were performed. The patients had either contraindications to surgery procedures or had a solitary kidney. The average tumor size was 37.5 mm (range, 18-59 mm) with the mean age of 68 years (range, 28-83 years). RFA were performed based on radiographic findings. Needle biopsy was made only twice. Monopolar Cool-tip Tyco or bipolar Celon Olympus radiofrequency devices were used. The procedure was performed under conscious sedation with local anesthesia. Treatment efficacy was assessed by computed tomography and by Doppler ultrasound. The absence of contrast enhancement on computed tomography was considered to be a successful treatment. The average follow up was 14 months (range, 3-36 months). In 42 tumors (93%), total absence of contrast enhancement was obtained after the initial RFA and in three tumors (7%) after the second ablation session. There were no complications following 41 procedures, including all ablations in small (<35 mm) renal masses. In four procedures, minor complications were observed. All patients are alive. There has been no need for chronic hemodialysis and, until now, we have not observed any local recurrences with the exception of one metastasis to an ipsilateral adrenal gland. RFA of kidney tumors is a promising alternative treatment which could be considered for patients who are not suitable for surgery. (author)

  18. New percutaneous ablative modalities in nephron-sparing surgery of small renal tumors

    Science.gov (United States)

    de Riese, Werner T. W.; Nelius, Thomas; Aronoff, David R.; Mittemeyer, Bernhard T.

    2004-07-01

    Renal tumors are increasingly detected on abdominal imaging studies. Standard treatment of small renal tumors includes partial or radical nephrectomy, done either open or laparoscopically. Several in situ ablative techniques to treat small renal lesions are currently in various phases of evolution. All involve imparting destructive energy to the tumor while minimizing injury to adjacent normal tissue. Cryotherapy (CryoT), radiofrequency ablation (RFA), high-intensity focused ultrasound (HIFUS) and high-intensity radiation (HIR) are all being evaluated as tools to ablate renal tumors. The goal with these modalities is to minimize the blood loss, tissue manipulation, and morbidity associated with excisional approaches. Animal studies have shown that large, reproducible lesions can be ablated in normal kidney tissue by these new techniques. Studies of human renal tissue response to RFA are just beginning. Ex vivo studies reveal large, reproducible controlled lesions in normal renal tissue, similar to animal studies. In vivo studies have shown no significant toxicity, while efficacy is currently under evaluation. Preliminary clinical studies in humans have revealed that renal tumors are slow to regress after treatment, but about 75% of these small renal tumors appeared well treated. Mixed responses have been observed in the remaining cases. This paper presents a concise review of efficacy, advantages and disadvantages of these new minimal invasive techniques and their possible clinical implication in the future.

  19. A thermal model for nanosecond pulsed laser ablation of aluminum

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2017-07-01

    Full Text Available In order to simulate the nanosecond pulsed laser ablation of aluminum, a novel model was presented for the target ablation and plume expansion. The simulation of the target ablation was based on one-dimensional heat conduction, taking into account temperature dependent material properties, phase transition, dielectric transition and phase explosion. While the simulation of the plume expansion was based on one-dimensional gas-dynamical equation, taking into account ionization, plume absorption and shielding. By coupling the calculations of the target ablation and plume expansion, the characteristics of the target and plume were obtained. And the calculated results were in good agreement with the experimental data, in terms of ablation threshold and depth within the fluence range of the tested laser. Subsequently, investigations were carried out to analyze the mechanisms of nanosecond pulsed laser ablation. The calculated results showed that the maximum surface temperature remained at about 90% of the critical temperature (0.9Tc due to phase explosion. Moreover, the plume shielding has significant effects on the laser ablation, and the plume shielding proportion increase as the laser fluence increasing. The ambient pressure belows 100 Pa is more suitable for laser ablation, which can obtained larger ablation depth.

  20. Radiofrequency (thermal) ablation versus no intervention or other interventions for hepatocellular carcinoma

    DEFF Research Database (Denmark)

    Weis, Sebastian; Franke, Annegret; Mössner, Joachim

    2013-01-01

    Hepatocellular carcinoma is the fifth most common cancer worldwide. Percutaneous interventional therapies, such as radiofrequency (thermal) ablation (RFA), have been developed for early hepatocellular carcinoma. RFA competes with other interventional techniques such as percutaneous ethanol...

  1. Planar strain analysis of liver undergoing microwave thermal ablation using x-ray CT.

    Science.gov (United States)

    Weiss, Noam; Goldberg, S Nahum; Nissenbaum, Yitzhak; Sosna, Jacob; Azhari, Haim

    2015-01-01

    To study the planar strain effects in liver during microwave (MW) thermal ablation as a means for tracking tissue expansion and contraction as a method for improving ablation monitoring. 1.4 mm circular metallic markers were inserted into 16 ex-vivo bovine fresh liver specimens, that were subsequently ablated (with the markers inside the specimen) by 40 W of microwave energy, for 1, 2, 3, 6, and 10 min. The markers were tracked during the ablation using an x-ray CT scanner. Images were acquired every 5-10 s enabling determination of the markers' coordinates over time. The 2D principal strains were calculated for triangles formed by subgroups of three markers, and their planar strain index, Ω, was plotted vs time. In addition, the radial distance of the markers from the antenna was measured at the end of each ablation. Subsequently, the tissue was sliced parallel to the imaged planes and the ablation zone was traced and digitized. The average ablation radius was then computed and compared to the radial distance. The planar strain, Ω(t), profile demonstrated an ascending pattern until reaching a maximum at about 180 s, with a mean peak value (Ω = 1.31 ± 0.04) indicating tissue expansion. Thereafter, Ω progressively declined over the remaining duration of the ablation treatment, indicating tissue contraction. Furthermore, when plotting the ablation size vs time and the markers' mean radial distance vs time, it was found that the two curves intercepted at a time corresponding to the time of peak planar strain. By detecting the point of maximal planar strain in tissues during MW application, it is possible to noninvasively identify the location of the ablation zone front. The fact that the liver tissue proximal to the ablated zone expands during the first part of the treatment and then contracts when the ablation front reaches it, may serve as an index for monitoring the thermal treatment.

  2. Rib fractures after percutaneous radiofrequency and microwave ablation of lung tumors: incidence and relevance.

    Science.gov (United States)

    Alexander, Erica S; Hankins, Carol A; Machan, Jason T; Healey, Terrance T; Dupuy, Damian E

    2013-03-01

    To retrospectively identify the incidence and probable risk factors for rib fractures after percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA) of neoplasms in the lung and to identify complications related to these fractures. Institutional review board approval was obtained for this HIPAA-compliant retrospective study. Study population was 163 patients treated with MWA and/or RFA for 195 lung neoplasms between February 2004 and April 2010. Follow-up computed tomographic images of at least 3 months were retrospectively reviewed by board-certified radiologists to determine the presence of rib fractures. Generalized estimating equations were performed to assess the effect that patient demographics, tumor characteristics, treatment parameters, and ablation zone characteristics had on development of rib fractures. Kaplan-Meier curve was used to estimate patients' probability of rib fracture after ablation as a function of time. Clinical parameters (ie, pain in ribs or chest, organ damage caused by fractured rib) were evaluated for patients with confirmed fracture. Rib fractures in proximity to the ablation zone were found in 13.5% (22 of 163) of patients. Estimated probability of fracture was 9% at 1 year and 22% at 3 years. Women were more likely than were men to develop fracture after ablation (P = .041). Patients with tumors closer to the chest wall were more likely to develop fracture (P = .0009), as were patients with ablation zones that involved visceral pleura (P = .039). No patients with rib fractures that were apparently induced by RFA and MWA had organ injury or damage related to fracture, and 9.1% (2 of 22) of patients reported mild pain. Rib fractures were present in 13.5% of patients after percutaneous RFA and MWA of lung neoplasms. Patients who had ablations performed close to the chest wall should be monitored for rib fractures.

  3. Heat Sink Effect on Tumor Ablation Characteristics as Observed in Monopolar Radiofrequency, Bipolar Radiofrequency, and Microwave, Using Ex Vivo Calf Liver Model

    Science.gov (United States)

    Pillai, Krishna; Akhter, Javid; Chua, Terence C.; Shehata, Mena; Alzahrani, Nayef; Al-Alem, Issan; Morris, David L.

    2015-01-01

    Abstract Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices. With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored. With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres. Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected. Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5. MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink. PMID:25738477

  4. A preoperative mathematic model for computed tomographic guided microwave ablation treatment of hepatic dome tumors.

    Science.gov (United States)

    Gao, Fei; Wang, Guo-Bao; Xiang, Zhan-Wang; Yang, Bin; Xue, Jing-Bing; Mo, Zhi-Qiang; Zhong, Zhi-Hui; Zhang, Tao; Zhang, Fu-Jun; Fan, Wei-Jun

    2016-05-03

    This study sought to prospectively evaluate the feasibility and safety of a preoperative mathematic model for computed tomographic(CT) guided microwave(MW) ablation treatment of hepatic dome tumors. This mathematic model was a regular cylinder quantifying appropriate puncture routes from the bottom up. A total of 103 patients with hepatic dome tumors were enrolled and randomly divided into 2 groups based on whether this model was used or not: Group A (using the model; n = 43) versus Group B (not using the model; n = 60). All tumors were treated by CT-guided MW ablation and follow-up contrast CT were reviewed. The average number of times for successful puncture, average ablation time, and incidence of right shoulder pain were less in Group A than Group B (1.4 vs. 2.5, P = 0.001; 8.8 vs. 11.1 minutes, P = 0.003; and 4.7% vs. 20%, P = 0.039). The technical success rate was higher in Group A than Group B (97.7% vs. 85.0%, P = 0.032). There were no significant differences between the two groups in primary and secondary technique efficacy rates (97.7% vs. 88.3%, P = 0.081; 90.0% vs. 72.7%, P = 0.314). No major complications occurred in both groups. The mathematic model of regular cylinder is feasible and safe for CT-guided MW ablation in treating hepatic dome tumors.

  5. Analysis of internal ablation for the thermal control of aerospace vehicles

    Science.gov (United States)

    Camberos, Jose A.; Roberts, Leonard

    1989-01-01

    A new method of thermal protection for transatmospheric vehicles is introduced. The method involves the combination of radiation, ablation and transpiration cooling. By placing an ablating material behind a fixed-shape, porous outer shield, the effectiveness of transpiration cooling is made possible while retaining the simplicity of a passive mechanism. A simplified one-dimensional approach is used to derive the governing equations. Reduction of these equations to non-dimensional form yields two parameters which characterize the thermal protection effectiveness of the shield and ablator combination for a given trajectory. The non-dimensional equations are solved numerically for a sample trajectory corresponding to glide re-entry. Four typical ablators are tested and compared with results obtained by using the thermal properties of water. For the present level of analysis, the numerical computations adequately support the analytical model.

  6. Characterisation of tissue shrinkage during microwave thermal ablation.

    Science.gov (United States)

    Farina, Laura; Weiss, Noam; Nissenbaum, Yitzhak; Cavagnaro, Marta; Lopresto, Vanni; Pinto, Rosanna; Tosoratti, Nevio; Amabile, Claudio; Cassarino, Simone; Goldberg, S Nahum

    2014-11-01

    The aim of this study was to characterise changes in tissue volume during image-guided microwave ablation in order to arrive at a more precise determination of the true ablation zone. The effect of power (20-80 W) and time (1-10 min) on microwave-induced tissue contraction was experimentally evaluated in various-sized cubes of ex vivo liver (10-40 mm ± 2 mm) and muscle (20 and 40 mm ± 2 mm) embedded in agar phantoms (N = 119). Post-ablation linear and volumetric dimensions of the tissue cubes were measured and compared with pre-ablation dimensions. Subsequently, the process of tissue contraction was investigated dynamically during the ablation procedure through real-time X-ray CT scanning. Overall, substantial shrinkage of 52-74% of initial tissue volume was noted. The shrinkage was non-uniform over time and space, with observed asymmetry favouring the radial (23-43 % range) over the longitudinal (21-29%) direction. Algorithmic relationships for the shrinkage as a function of time were demonstrated. Furthermore, the smallest cubes showed more substantial and faster contraction (28-40% after 1 min), with more considerable volumetric shrinkage (>10%) in muscle than in liver tissue. Additionally, CT imaging demonstrated initial expansion of the tissue volume, lasting in some cases up to 3 min during the microwave ablation procedure, prior to the contraction phenomenon. In addition to an asymmetric substantial shrinkage of the ablated tissue volume, an initial expansion phenomenon occurs during MW ablation. Thus, complex modifications of the tissue close to a radiating antenna will likely need to be taken into account for future methods of real-time ablation monitoring.

  7. Creation of a Tumor-Mimic Model Using a Muscle Paste for Radiofrequency Ablation of the Lung

    International Nuclear Information System (INIS)

    Kawai, T.; Kaminou, T.; Sugiura, K.; Hashimoto, M.; Ohuchi, Y.; Adachi, A.; Fujioka, S.; Ito, H.; Nakamura, K.; Ogawa, T.

    2009-01-01

    The purpose of this study was to develop an easily created tumor-mimic model and evaluate its efficacy for radiofrequency ablation (RFA) of the lung. The bilateral lungs of eight living adult swine were used. A tumor-mimic model was made by percutaneous injection of 1.0 ml muscle paste through the bone biopsy needle into the lung. An RFA probe was then inserted into the tumor mimics immediately after tumor creation. Ablation time, tissue impedance, and temperature were recorded. The tumor mimics and their coagulated regions were evaluated microscopically and macroscopically. The muscle paste was easily injected into the lung parenchyma through the bone biopsy needle and well visualized under fluoroscopy. In 10 of 12 sites the tumor mimics were oval shaped, localized, and homogeneous on gross specimens. Ten tumor mimics were successfully ablated, and four locations were ablated in the normal lung parenchyma as controls. In the tumor and normal lung parenchyma, ablation times were 8.9 ± 3.5 and 4.4 ± 1.6 min, respectively; tissue impedances at the start of ablation were 100.6 ± 16.6 and 145.8 ± 26.8 Ω, respectively; and temperatures at the end of ablation were 66.0 ± 7.9 and 57.5 ± 7.6 o C, respectively. The mean size of tumor mimics was 13.9 x 8.2 mm, and their coagulated area was 18.8 x 13.1 mm. In the lung parenchyma, the coagulated area was 15.3 x 12.0 mm. In conclusion, our tumor-mimic model using muscle paste can be easily and safely created and can be ablated using the ablation algorithm in the clinical setting.

  8. Thyroid tissue: US-guided percutaneous laser thermal ablation.

    Science.gov (United States)

    Pacella, Claudio Maurizio; Bizzarri, Giancarlo; Spiezia, Stefano; Bianchini, Antonio; Guglielmi, Rinaldo; Crescenzi, Anna; Pacella, Sara; Toscano, Vincenzo; Papini, Enrico

    2004-07-01

    To evaluate in vivo the safety and effectiveness of percutaneous laser thermal ablation (LTA) in the debulking of thyroid lesions. Twenty-five adult patients at poor surgical risk with cold nodules (n = 8), autonomously hyperfunctioning thyroid nodules (n = 16), or anaplastic carcinoma (n = 1) underwent LTA. One to four 21-gauge spinal needles were inserted with ultrasonographic (US) guidance into the thyroid lesions. A 300-microm-diameter quartz optical fiber was advanced through the sheath of the needle. Nd:YAG laser was used with output power of 3-5 W. Side effects, complications, and clinical and hormonal changes were evaluated at the end of LTA and during follow-up. Linear regression analysis was used to investigate the correlation between energy delivered and reduction in nodule volume. Volume of induced necrosis and reduction in nodule volume were assessed with US or computed tomography. LTA was performed without difficulties in 76 LTA sessions. After treatment with 5 W, two patients experienced mild dysphonia, which resolved after 48 hours and 2 months. Improvement of local compression symptoms was experienced by 12 of 14 (86%) patients. Thyroid-stimulating hormone (TSH) was detectable in five of 16 (31%) patients with hyperfunctioning nodules at 6 months after LTA. Volume of induced necrosis ranged from 0.8 to 3.9 mL per session. Anaplastic carcinoma treated with four fibers yielded 32.0 mL of necrosis. Echo structure and baseline volume did not influence response. Energy load and reduction in nodule volume were significantly correlated (r(2) =.75, P nodule volume reduction at 6 months in hyperfunctioning nodules was 3.3 mL +/- 2.8 (62% +/- 21.4 [SD]) and in cold nodules was 7.7 mL +/- 7.5 (63% +/- 13.8). LTA may be a therapeutic tool for highly selected problems in the treatment of thyroid lesions. Copyright RSNA, 2004

  9. Percutaneous Image-guided Radiofrequency Ablation of Tumors in Inoperable Patients - Immediate Complications and Overall Safety.

    Science.gov (United States)

    Sahay, Anubha; Sahay, Nishant; Kapoor, Ashok; Kapoor, Jyoti; Chatterjee, Abhishek

    2016-01-01

    Percutaneous destruction of cancer cells using a radiofrequency energy source has become an accepted part of the modern armamentarium for managing malignancies. Radiofrequency ablation (RFA) is a relatively novel procedure for treating recurrent and metastatic tumors. It is used for debulking tumors and as adjuvant therapy for palliative care apart from its role as a pain management tool. Its use in the third world countries is limited by various factors such as cost and expertise. In the remotest parts of India, where economic development has been slow, abject poverty with poor health care facilities advanced malignancies present a challenge to health care providers. We undertook this study to assess the safety of the percutaneous RFA tumor ablation as a therapeutic or palliative measure in patients where surgery was not possible. We observed that RFA may be an effective, alternative therapeutic modality for some inoperable tumors where other therapeutic modalities cannot be considered. Palliative and therapeutic image-guided RFAs of tumors may be the only treatment option in patients who are inoperable for a variety of reasons. To assess the safety and complications of RFA in such a patient population is important before embarking upon any interventions given their physically, mentally, and socially compromised status in a country such as India. To assess the safety of percutaneous image-guided radiofrequency tumor ablation and to note the various immediate and early complications of the intervention. This was a prospective, observational study conducted in Tata Main Hospital, Jamshedpur, Jharkhand, India. After approval by the Hospital Approval Committee all patients who consented for percutaneous RFA of their tumor admitted in the hospital were included after taking fully informed consent from patient/close relative keeping the following criteria in view. Patients who were likely to derive a direct benefit in the survival or as a palliative measure for relief

  10. Radiofrequency thermal ablation of a metastatic lung nodule

    Energy Technology Data Exchange (ETDEWEB)

    Highland, Adrian M. [Department of Clinical Radiology, Hull Royal Infirmary, Anlaby Road, Hull, HU3 2JZ (United Kingdom); Mack, Paul [Diana Princess of Wales Hospital, Scartho Road, Grimsby, DN33 2BA (United Kingdom); Breen, David J. [Department of Radiology, Southampton University Hospitals, Tremona Road, Southampton, SO16 6YD (United Kingdom)

    2002-07-01

    Pulmonary metastases are a common finding in patients with colonic adenocarcinoma. We report the treatment of a metastatic lung nodule with radiofrequency (RF) ablation under CT guidance. This case illustrates the use of RF ablation in a patient in whom surgical resection was no longer possible and where chemotherapy was unlikely to produce benefit. This technique may offer a viable method of cytoreduction when other treatments have not succeeded. (orig.)

  11. Radiofrequency thermal ablation of a metastatic lung nodule

    International Nuclear Information System (INIS)

    Highland, Adrian M.; Mack, Paul; Breen, David J.

    2002-01-01

    Pulmonary metastases are a common finding in patients with colonic adenocarcinoma. We report the treatment of a metastatic lung nodule with radiofrequency (RF) ablation under CT guidance. This case illustrates the use of RF ablation in a patient in whom surgical resection was no longer possible and where chemotherapy was unlikely to produce benefit. This technique may offer a viable method of cytoreduction when other treatments have not succeeded. (orig.)

  12. Composite Configuration Interventional Therapy Robot for the Microwave Ablation of Liver Tumors

    Science.gov (United States)

    Cao, Ying-Yu; Xue, Long; Qi, Bo-Jin; Jiang, Li-Pei; Deng, Shuang-Cheng; Liang, Ping; Liu, Jia

    2017-11-01

    The existing interventional therapy robots for the microwave ablation of liver tumors have a poor clinical applicability with a large volume, low positioning speed and complex automatic navigation control. To solve above problems, a composite configuration interventional therapy robot with passive and active joints is developed. The design of composite configuration reduces the size of the robot under the premise of a wide range of movement, and the robot with composite configuration can realizes rapid positioning with operation safety. The cumulative error of positioning is eliminated and the control complexity is reduced by decoupling active parts. The navigation algorithms for the robot are proposed based on solution of the inverse kinematics and geometric analysis. A simulation clinical test method is designed for the robot, and the functions of the robot and the navigation algorithms are verified by the test method. The mean error of navigation is 1.488 mm and the maximum error is 2.056 mm, and the positioning time for the ablation needle is in 10 s. The experimental results show that the designed robot can meet the clinical requirements for the microwave ablation of liver tumors. The composite configuration is proposed in development of the interventional therapy robot for the microwave ablation of liver tumors, which provides a new idea for the structural design of medical robots.

  13. Local recurrence after laparoscopic radiofrequency ablation of malignant liver tumors: Results of a contemporary series.

    Science.gov (United States)

    Takahashi, Hideo; Akyuz, Muhammet; Aksoy, Erol; Karabulut, Koray; Berber, Eren

    2017-06-01

    The aims of this study were to determine the incidence of Local recurrence (LR) in patients at long-term follow-up after laparoscopic RFA (LRFA) and also to determine the risk factors for LR from a contemporary series. Patients undergoing LRFA between 2005 and 2014 by a single surgeon were reviewed. Demographic and perioperative data were analyzed from a prospective database. LRFA was performed on 316 patients with 901 lesions. Median follow-up was 25 months, with 76% of whom completed at least one year of follow-up. The LR rate was 18.4%. The LR in patients followed for less than 12 months was 13.8%, 20.3% for 12 months, and 19.7% for 18 months (P = 0.02). One-fourth of the LRs developed after the 1st year. Morbidity was 8.9% and mortality 0.3%. Tumor type, size, ablation margin, and surgeon experience affected LR, with tumor type, size, and ablation margin being independent. This study shows that 14% of malignant liver tumors will develop LR within a year after LRFA. Additional 4% of the lesions will demonstrate recurrence within 1 cm of the ablation zone, mostly as part of a multifocal recurrence. Ablation margin is the only parameter that the surgeon can manipulate to decrease LR. © 2017 Wiley Periodicals, Inc.

  14. Effects of Androgen Ablation on Anti-Tumor Immunity

    National Research Council Canada - National Science Library

    Kast, Martin

    2004-01-01

    .... This AA induced autoimmune-like response exerts limited anti-tumor activity in a murine prostate cancer model, but could be synergistic with CTLA-4 blockade that promotes the development of autoreactive T cell...

  15. Feasibility of saline infusion on the liver surface during radiofrequency ablation of subcapsuIar hepatic tumor: an experimentaI study

    International Nuclear Information System (INIS)

    Lee, Young Rang; Kim, Young Sun; Rhim, Hyun Chul; Seo, Heung Suk; Cho, On Koo; Koh, Byung Hee; Kim, Yong Soo; Kim, Sung Kyu; Paik, Seung Sam

    2004-01-01

    The purpose of the study was to evaluate the feasibility of infusion of normal saline onto the surface of the liver capsule for minimizing thermal injury of the adjacent organs during radiofrequency ablation of subcapsular hepatic tumor in an ex-vivo porcine model. We used porcine small bowel with it's serosal surface spread onto the porcine liver as an experiment model. The puncturing electrode was inserted into a 6 Fr introducer sheath, and the introducer sheath was connected to the infusion pump for creating a saline flow over the liver surface. A total of 15 ablations were divided into the control group (n=5), intermittent saline infusion group (n=5) and continuous saline infusion (n=5) group. The ablations were done during 3 minutes, and the infusion was set at 2 ml/min and stopped every 30 seconds in the intermittent saline infusion group. After the ablation, we measured the size of the ablated lesion on the surface of bowel and liver, and we also measured the depth of hepatic lesion. Ablated areas of bowel and liver surface in the control group, intermittent saline infusion group and continuous infusion group were 210.7±89.1 mm 2 , 74.6±27.2 mm 2 and 35.8±43.4 mm 2 , respectively, and 312.6±73.6 mm 2 , 228.4±110.5 mm 2 , and 80.9±55.1 mm 2 , respectively. In contrast to the broad base of the ablated area on the surface of the liver in the control group, the shapes of the lesions became narrower approaching to the liver surface in all cases of the continuous saline infusion group, and the shapes of the lesions were broad based in 3 cases and narrow based in 2 cases of the intermittent saline infusion group. Continuous infusion of normaI saline onto the surface of the liver during radiofrequency ablation of subcapsular hepatic tumor is a feasible method for minimizing thermal injury of the adjacent organs. Further exploration of the optimal parameters or techniques to maximize the hepatic ablation and simultaneously to minimize the thermal injury of

  16. An image-guided system for optimized volumetric treatment planning and execution for radiofrequency ablation of liver tumors

    Energy Technology Data Exchange (ETDEWEB)

    Banovac, F.; Popa, T.; Cheng, P.; Cleary, K. [Computer Aided Interventions and Medical Robotics (CAIMR), Imaging Science and Information Systems (ISIS) Center, Georgetown Univ. Medical Center, Washington, DC (United States); Abeledo, H.; Campos-Nanez, E. [Dept. of Engineering Management and System Engineering, George Washington Univ., Washington, DC (United States); Wood, B.J. [Diagnostic Radiology Dept., NIH Clinical Center, Bethesda, MD (United States)

    2007-06-15

    Radiofrequency ablation of liver tumors is becoming an increasingly popular option for the treatment of cancer. However, the procedure has several technical challenges, mostly associated with precision targeting of the tumor and ensuring complete ablation coverage. In this paper we describe an image-guided system that we are developing for improved visualization and probe placement during these procedures. The system will include a pre-procedure optimization module and an intra-procedure guidance component. The system concept is explained and some preliminary results are given. While this system is designed for radiofrequency ablation of liver tumors, the methods are applicable to other organs and treatment methods. (orig.)

  17. [Regression and therapy-resistance of primary liver tumors and liver metastases after regional chemotherapy and local tumor ablation].

    Science.gov (United States)

    Fischer, H-P

    2005-05-01

    High dosage regional chemotherapy, chemoembolization and other methods of regional treatment are commonly used to treat unresectable primary liver malignancies and liver metastases. In liver malignancies of childhood neoadjuvant chemotherapy is successfully combined with surgical treatment. Chemotherapy and local tumor ablation lead to characteristic histomorphologic changes: Complete destruction of the tumor tissue and its vascular bed is followed by encapsulated necroses. After selective eradication of the tumor cells under preservation of the fibrovasular bed the tumor is replaced by hypocellular edematous and fibrotic tissue. If completely damaged tumor tissue is absorbed quickly, the tumor area is replaced by regenerating liver tissue. Obliterating fibrohyalinosis of tumor vessels, and perivascular edema or necrosis indicate tissue damage along the vascular bed. Degenerative pleomorphism of tumor cells, steatosis, hydropic swelling and Malloryhyalin in HCC can represent cytologic findings of cytotoxic cellular damage. Macroscopic type of HCC influences significantly the response to treatment. Multinodular HCC often contain viable tumor nodules close to destroyed nodules after treatment. Encapsulated uninodular tumors undergo complete necrosis much easier. Large size and a tumor capsule limitate the effect of percutaneous injection of ethanol into HCC. In carcinomas with an infiltrating border, especially in metastases of adenocarcinomas and hepatic cholangiocarcinoma cytostatic treatment damages the tumor tissue mainly in the periphery. Nevertheless the infiltrating rim, portal veins, lymphatic spaces and bile ducts as well as the angle between liver capsule, tumor nodule and bordering parenchyma are the main refugees of viable tumor tissue even after high dosage regional chemotherapy. This local resistance is caused by special local conditions of vascularization and perfusion. These residues are the source of local tumor progression and distant metastases

  18. Comprehensive preclinical evaluation of a multi-physics model of liver tumor radiofrequency ablation.

    Science.gov (United States)

    Audigier, Chloé; Mansi, Tommaso; Delingette, Hervé; Rapaka, Saikiran; Passerini, Tiziano; Mihalef, Viorel; Jolly, Marie-Pierre; Pop, Raoul; Diana, Michele; Soler, Luc; Kamen, Ali; Comaniciu, Dorin; Ayache, Nicholas

    2017-09-01

    We aim at developing a framework for the validation of a subject-specific multi-physics model of liver tumor radiofrequency ablation (RFA). The RFA computation becomes subject specific after several levels of personalization: geometrical and biophysical (hemodynamics, heat transfer and an extended cellular necrosis model). We present a comprehensive experimental setup combining multimodal, pre- and postoperative anatomical and functional images, as well as the interventional monitoring of intra-operative signals: the temperature and delivered power. To exploit this dataset, an efficient processing pipeline is introduced, which copes with image noise, variable resolution and anisotropy. The validation study includes twelve ablations from five healthy pig livers: a mean point-to-mesh error between predicted and actual ablation extent of 5.3 ± 3.6 mm is achieved. This enables an end-to-end preclinical validation framework that considers the available dataset.

  19. Image-guided radiofrequency ablation of Bosniak category III or IV cystic renal tumors: initial clinical experience

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byung Kwan; Kim, Chan Kyo [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Samsung Medical Center, Seoul (Korea); Lee, Hyun Moo [Sungkyunkwan University School of Medicine, Department of Urology, Samsung Medical Center, Seoul (Korea)

    2008-07-15

    The purpose of this study was to assess the efficacy of image-guided radiofrequency (RF) ablation of cystic renal tumors. Between November 2005 and August 2007, computed tomography (CT) or ultrasound-guided RF ablation was performed in nine patients with 14 Bosniak category III (n = 5) or IV (n = 9) cystic renal tumors using an internally cooled RF ablation system. We evaluated the number of sessions, cycles and duration of energy application, treatment results, lesion size change, and complications. Together the cystic renal tumors required 15 sessions and 23 cycles of energy application. The duration of energy application per one tumor ablation ranged from 1 to 12 min (mean 6 min). The last follow-up CT indicated complete coagulation of 14/14 (100%) lesions. None of these tumors had recurred within 1-19 months (mean 8 months). The maximum diameter of the cystic renal tumors was significantly reduced from 2.5 {+-} 0.6 cm before ablation to 1.7 {+-} 0.7 cm at the last follow-up CT (P < 0.01). Complications were pneumothorax (n = 2), inguinal paresthesia (n = 1), and arteriovenous fistula (n = 1). Image-guided RF ablation is an effective treatment for Bosniak category III or IV cystic renal tumors, which might need relatively shorter duration of energy application than purely solid renal tumors of the same size. (orig.)

  20. Image-guided radiofrequency ablation of Bosniak category III or IV cystic renal tumors: initial clinical experience

    International Nuclear Information System (INIS)

    Park, Byung Kwan; Kim, Chan Kyo; Lee, Hyun Moo

    2008-01-01

    The purpose of this study was to assess the efficacy of image-guided radiofrequency (RF) ablation of cystic renal tumors. Between November 2005 and August 2007, computed tomography (CT) or ultrasound-guided RF ablation was performed in nine patients with 14 Bosniak category III (n = 5) or IV (n = 9) cystic renal tumors using an internally cooled RF ablation system. We evaluated the number of sessions, cycles and duration of energy application, treatment results, lesion size change, and complications. Together the cystic renal tumors required 15 sessions and 23 cycles of energy application. The duration of energy application per one tumor ablation ranged from 1 to 12 min (mean 6 min). The last follow-up CT indicated complete coagulation of 14/14 (100%) lesions. None of these tumors had recurred within 1-19 months (mean 8 months). The maximum diameter of the cystic renal tumors was significantly reduced from 2.5 ± 0.6 cm before ablation to 1.7 ± 0.7 cm at the last follow-up CT (P < 0.01). Complications were pneumothorax (n = 2), inguinal paresthesia (n = 1), and arteriovenous fistula (n = 1). Image-guided RF ablation is an effective treatment for Bosniak category III or IV cystic renal tumors, which might need relatively shorter duration of energy application than purely solid renal tumors of the same size. (orig.)

  1. Heat Stress-Induced PI3K/mTORC2-Dependent AKT Signaling Is a Central Mediator of Hepatocellular Carcinoma Survival to Thermal Ablation Induced Heat Stress.

    Directory of Open Access Journals (Sweden)

    Scott M Thompson

    Full Text Available Thermal ablative therapies are important treatment options in the multidisciplinary care of patients with hepatocellular carcinoma (HCC, but lesions larger than 2-3 cm are plagued with high local recurrence rates and overall survival of these patients remains poor. Currently no adjuvant therapies exist to prevent local HCC recurrence in patients undergoing thermal ablation. The molecular mechanisms mediating HCC resistance to thermal ablation induced heat stress and local recurrence remain unclear. Here we demonstrate that the HCC cells with a poor prognostic hepatic stem cell subtype (Subtype HS are more resistant to heat stress than HCC cells with a better prognostic hepatocyte subtype (Subtype HC. Moreover, sublethal heat stress rapidly induces phosphoinositide 3-kinase (PI3K/mammalian target of rapamycin (mTOR dependent-protein kinase B (AKT survival signaling in HCC cells in vitro and at the tumor ablation margin in vivo. Conversely, inhibition of PI3K/mTOR complex 2 (mTORC2-dependent AKT phosphorylation or direct inhibition of AKT function both enhance HCC cell killing and decrease HCC cell survival to sublethal heat stress in both poor and better prognostic HCC subtypes while mTOR complex 1 (mTORC1-inhibition has no impact. Finally, we showed that AKT isoforms 1, 2 and 3 are differentially upregulated in primary human HCCs and that overexpression of AKT correlates with worse tumor biology and pathologic features (AKT3 and prognosis (AKT1. Together these findings define a novel molecular mechanism whereby heat stress induces PI3K/mTORC2-dependent AKT survival signaling in HCC cells and provide a mechanistic rationale for adjuvant AKT inhibition in combination with thermal ablation as a strategy to enhance HCC cell killing and prevent local recurrence, particularly at the ablation margin.

  2. Therapy of Pancreatic Neuroendocrine Tumors: Fine Needle Intervention including Ethanol and Radiofrequency Ablation

    Directory of Open Access Journals (Sweden)

    Sundeep Lakhtakia

    2017-11-01

    Full Text Available Pancreatic neuroendocrine tumors (PNETs are increasingly being detected, though usually as incidental findings. Majority of the PNETs are non-functional and surgical resection is the standard of care for most of them. However, in patients with small PNETs localized within the pancreas, who are unfit or unwilling for surgery, alternate methods of treatment are needed. Direct methods of ablation of PNETs, using either ethanol injection or radiofrequency ablation (RFA, are emerging as effective methods. The limited literature available as case reports or case series on endoscopic ultrasound (EUS-guided local ablation using either ethanol or RFA has demonstrated safety and efficacy along with short- to medium-term sustained relief. Long-term benefits with these local ablative therapies are awaited. Comparative studies are needed to show which of these two competing technologies is superior. Finally, comparative trials of EUS-guided ablation with surgical resection in terms of efficacy and safety will ensure their place in the management algorithm.

  3. Transluminal radio-frequency thermal ablation using a stent-type electrode: an experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Sun; Rhim, Hyun Chul [Hanyang University College of Medicine, Seoul (Korea, Republic of); Song, Ho Young [Asan Medical Center, Seoul (Korea, Republic of)] [and others

    2003-06-01

    To assess the feasibility of transluminal radiofrequency thermal ablation using a stent-type electrode and to determine, by means of in-vivo and in-vivo animal studies, the appropriate parameters. In-vivo: the radiofrequency electrode used was a self-expandable nitinol stent with 1cm insulated ends. A stent was placed in the portal vein of bovine liver, and ablations at target temperatures of 70, 80, 90, and 100 .deg. C were performed. Ablated sizes were measured longitudinally. In vivo: four mongrel dogs were anesthetized, and a stent was inserted in the common bile duct under fluoroscopic guidance through an ultrasound-guided gall bladder puncture site. The ablation temperature was set at 80 .deg. C, and each dog underwent proximal and distal esophageal ablations lasting 12 minutes. They were sacrificed immediately. In-vivo: ablated sizes showed significant correlation with target temperatures (r>0.04; p<0.05). Although most lesions were fusiform, dumbbell-shaped lesions with central thinning were found in two cases in the 70 .deg. C group. In all cases in the 70 .deg. C and 80 .deg. C group, the length of the insulated segment was less than 1cm. In-vivo: at microscopy, tissues at the center of the biliary stent showed more prominent pathological change than those at the periphery while those remote from the stent showed minimal or no change. In esophageal ablations, the mean highest temperature was 48.6 .deg. C. Microscopy demonstrated the destruction and shedding of mucosa, edema, and coagulation necrosis of submucosa, but in muscle layers no abnormalities were apparent. Transluminal radio-frequency thermal ablation using a stent-type electrode may be useful for elongating patency. The appropriate target temperature for biliary ablation is 80 .deg. C.

  4. Angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors in the liver: A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Il; Shin, Min Woo; Shin, Won Seon [Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); and others

    2016-09-15

    To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin. In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25–35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10–26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors' epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications. Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3–12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21–1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients. Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate.

  5. Angled Cool-Tip Electrode for Radiofrequency Ablation of Small Superficial Subcapsular Tumors in the Liver: A Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Il [Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of); Kim, Il Jung [Department of Radiology, Bucheon St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Bucheon 14647 (Korea, Republic of); Lee, Shin Jae [Department of Radiology, CHA Bundang Medical Center, CHA University, Seongnam 13496 (Korea, Republic of); Shin, Min Woo; Shin, Won Sun; Chung, Yong Eun; Kim, Gyoung Min; Kim, Man Deuk; Won, Jong Yun; Lee, Do Yun [Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of); Choi, Jin Sub [Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of); Han, Kwang-Hyub [Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of)

    2016-11-01

    To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin. In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25–35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10–26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors' epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications. Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3–12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21–1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients. Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate.

  6. Angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors in the liver: A feasibility study

    International Nuclear Information System (INIS)

    Park, Sung Il; Shin, Min Woo; Shin, Won Seon

    2016-01-01

    To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin. In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25–35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10–26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors' epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications. Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3–12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21–1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients. Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate

  7. Angled Cool-Tip Electrode for Radiofrequency Ablation of Small Superficial Subcapsular Tumors in the Liver: A Feasibility Study

    International Nuclear Information System (INIS)

    Park, Sung Il; Kim, Il Jung; Lee, Shin Jae; Shin, Min Woo; Shin, Won Sun; Chung, Yong Eun; Kim, Gyoung Min; Kim, Man Deuk; Won, Jong Yun; Lee, Do Yun; Choi, Jin Sub; Han, Kwang-Hyub

    2016-01-01

    To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin. In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25–35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10–26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors' epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications. Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3–12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21–1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients. Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate

  8. Endoscopic ultrasound-guided radiofrequency ablation for management of benign solid pancreatic tumors.

    Science.gov (United States)

    Choi, Jun-Ho; Seo, Dong-Wan; Song, Tae Jun; Park, Do Hyun; Lee, Sang Soo; Lee, Sung Koo; Kim, Myung-Hwan

    2018-05-04

     Radiofrequency ablation (RFA) has been increasingly employed in experimental and clinical settings for the management of pancreatic lesions. This study aimed to assess the safety and efficacy of endoscopic ultrasound (EUS)-guided RFA for benign solid pancreatic tumors.  In a single-center, prospective study, 10 patients with benign solid pancreatic tumors underwent EUS-RFA. After the RFA electrode had been inserted into the pancreatic mass, the radiofrequency generator was activated to deliver 50 W of ablation power.  Among the 10 patients, 16 sessions of EUS-RFA were successfully performed. Diagnoses included nonfunctioning neuroendocrine tumor (n = 7), solid pseudopapillary neoplasm (n = 2), and insulinoma (n = 1); the median largest diameter of the tumors was 20 mm (range 8 - 28 mm). During follow-up (median 13 months), radiologic complete response was achieved in seven patients. Two adverse events (12.4 %; 1 moderate and 1 mild) occurred.  EUS-RFA may be a safe and potentially effective treatment option in selected patients with benign solid pancreatic tumors. Multiple sessions may be required if there is a remnant tumor, and adverse events must be carefully monitored. © Georg Thieme Verlag KG Stuttgart · New York.

  9. Study of organic ablative thermal-protection coating for solid rocket motor

    Science.gov (United States)

    Hua, Zenggong

    1992-06-01

    A study is conducted to find a new interior thermal-protection material that possesses good thermal-protection performance and simple manufacturing possibilities. Quartz powder and Cr2O3 are investigated using epoxy resin as a binder and Al2O3 as the burning inhibitor. Results indicate that the developed thermal-protection coating is suitable as ablative insulation material for solid rocket motors.

  10. Laser-induced thermo ablation of hepatic tumors: an update review

    International Nuclear Information System (INIS)

    D'Ippolito, Giuseppe; Ribeiro, Marcelo

    2004-01-01

    Laser-induced thermo ablation has been used as a reliable method for producing coagulation necrosis in hepatic tumors in patients who are not suitable for surgical treatment. The procedure can be performed percutaneously, using image-guiding methods, by open laparotomy or laparoscopy. We review the current literature and discuss the principles, indications, complications and clinical results as well as the potential limitations and contraindications of this novel technique. (author)

  11. Multitriggered Tumor-Responsive Drug Delivery Vehicles Based on Protein and Polypeptide Coassembly for Enhanced Photodynamic Tumor Ablation.

    Science.gov (United States)

    Zhang, Ning; Zhao, Fenfang; Zou, Qianli; Li, Yongxin; Ma, Guanghui; Yan, Xuehai

    2016-11-01

    Tumor-responsive nanocarriers are highly valuable and demanded for smart drug delivery particularly in the field of photodynamic therapy (PDT), where a quick release of photosensitizers in tumors is preferred. Herein, it is demonstrated that protein-based nanospheres, prepared by the electrostatic assembly of proteins and polypeptides with intermolecular disulfide cross-linking and surface polyethylene glycol coupling, can be used as versatile tumor-responsive drug delivery vehicles for effective PDT. These nanospheres are capable of encapsulation of various photosensitizers including Chlorin e6 (Ce6), protoporphyrin IX, and verteporfin. The Chlorin e6-encapsulated nanospheres (Ce6-Ns) are responsive to changes in pH, redox potential, and proteinase concentration, resulting in multitriggered rapid release of Ce6 in an environment mimicking tumor tissues. In vivo fluorescence imaging results indicate that Ce6-Ns selectively accumulate near tumors and the quick release of Ce6 from Ce6-Ns can be triggered by tumors. In tumors the fluorescence of released Ce6 from Ce6-Ns is observed at 0.5 h postinjection, while in normal tissues the fluorescence appeared at 12 h postinjection. Tumor ablation is demonstrated by in vivo PDT using Ce6-Ns and the biocompatibility of Ce6-Ns is evident from the histopathology imaging, confirming the enhanced in vivo PDT efficacy and the biocompatibility of the assembled drug delivery vehicles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Use of High-Frequency Jet Ventilation for Percutaneous Tumor Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Denys, Alban, E-mail: alban.denys@chuv.ch; Lachenal, Yann; Duran, Rafael [Lausanne University Hospital, Department of Radiology and Interventional Radiology (Switzerland); Chollet-Rivier, Madeleine [Lausanne University Hospital, Department of Anesthesiology (Switzerland); Bize, Pierre [Lausanne University Hospital, Department of Radiology and Interventional Radiology (Switzerland)

    2013-05-02

    PurposeTo report feasibility and potential benefits of high-frequency jet ventilation (HFJV) in tumor ablations techniques in liver, kidney, and lung lesions.MethodsThis prospective study included 51 patients (14 women, mean age 66 years) bearing 66 tumors (56 hepatic, 5 pulmonary, 5 renal tumors) with a median size of 16 ± 8.7 mm, referred for tumor ablation in an intention-to-treat fashion before preoperative anesthesiology visit. Cancellation and complications of HFJV were prospectively recorded. Anesthesia and procedure duration, as well as mean CO{sub 2} capnea, were recorded. When computed tomography guidance was used, 3D spacial coordinates of an anatomical target <2 mm in diameter on 8 slabs of 4 slices of 3.75-mm slice thickness were registered.ResultsHFJV was used in 41 of 51 patients. Of the ten patients who were not candidate for HFJV, two patients had contraindication to HFJV (severe COPD), three had lesions invisible under HFJV requiring deep inspiration apnea for tumor targeting, and five patients could not have HFJV because of unavailability of a trained anesthetic team. No specific complication or hypercapnia related to HFJV were observed despite a mean anesthetic duration of 2 h and ventilation performed in procubitus (n = 4) or lateral decubitus (n = 6). Measured internal target movement was 0.3 mm in x- and y-axis and below the slice thickness of 3.75 mm in the z-axis in 11 patients.ConclusionsHFJV is feasible in 80 % of patients allowing for near immobility of internal organs during liver, kidney, and lung tumor ablation.

  13. Hyaluronic Acid Gel Injection to Prevent Thermal Injury of Adjacent Gastrointestinal Tract during Percutaneous Liver Radiofrequency Ablation

    International Nuclear Information System (INIS)

    Hasegawa, Takaaki; Takaki, Haruyuki; Miyagi, Hideki; Nakatsuka, Atsuhiro; Uraki, Junji; Yamanaka, Takashi; Fujimori, Masashi; Sakuma, Hajime; Yamakado, Koichiro

    2013-01-01

    This study evaluated the safety, feasibility, and clinical utility of hyaluronic acid gel injection to separate the gastrointestinal tract from the tumor during liver radiofrequency ablation (RFA). Eleven patients with liver tumors measuring 0.9–3.5 cm (mean ± standard deviation, 2.1 ± 0.8 cm) that were adjacent to the gastrointestinal tracts received RFA after the mixture of hyaluronic acid gel and contrast material (volume, 26.4 ± 14.5 mL; range, 10–60 mL) was injected between the tumor and the gastrointestinal tract under computed tomographic–fluoroscopic guidance. Each tumor was separated from the gastrointestinal tract by 1.0–1.5 cm (distance, 1.2 ± 0.2 cm) after injection of hyaluronic acid gel, and subsequent RFA was performed without any complications in all patients. Although tumor enhancement disappeared in all patients, local tumor progression was found in a patient (9.1 %, 1 of 11) during the follow-up of 5.5 ± 3.2 months (range, 0.4–9.9 months). In conclusion, hyaluronic acid gel injection is a safe and useful technique to avoid thermal injury of the adjacent gastrointestinal tract during liver RFA

  14. Hyaluronic Acid Gel Injection to Prevent Thermal Injury of Adjacent Gastrointestinal Tract during Percutaneous Liver Radiofrequency Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Takaaki, E-mail: hasegawat@clin.medic.mie-u.ac.jp; Takaki, Haruyuki; Miyagi, Hideki; Nakatsuka, Atsuhiro; Uraki, Junji; Yamanaka, Takashi; Fujimori, Masashi; Sakuma, Hajime; Yamakado, Koichiro [Mie University School of Medicine, Department of Radiology (Japan)

    2013-08-01

    This study evaluated the safety, feasibility, and clinical utility of hyaluronic acid gel injection to separate the gastrointestinal tract from the tumor during liver radiofrequency ablation (RFA). Eleven patients with liver tumors measuring 0.9-3.5 cm (mean {+-} standard deviation, 2.1 {+-} 0.8 cm) that were adjacent to the gastrointestinal tracts received RFA after the mixture of hyaluronic acid gel and contrast material (volume, 26.4 {+-} 14.5 mL; range, 10-60 mL) was injected between the tumor and the gastrointestinal tract under computed tomographic-fluoroscopic guidance. Each tumor was separated from the gastrointestinal tract by 1.0-1.5 cm (distance, 1.2 {+-} 0.2 cm) after injection of hyaluronic acid gel, and subsequent RFA was performed without any complications in all patients. Although tumor enhancement disappeared in all patients, local tumor progression was found in a patient (9.1 %, 1 of 11) during the follow-up of 5.5 {+-} 3.2 months (range, 0.4-9.9 months). In conclusion, hyaluronic acid gel injection is a safe and useful technique to avoid thermal injury of the adjacent gastrointestinal tract during liver RFA.

  15. Laser ablation characteristics of metallic materials: Role of Debye-Waller thermal parameter

    International Nuclear Information System (INIS)

    Butt, M Z

    2014-01-01

    The interaction of a high intensity laser pulse with a solid target results in the formation of a crater and a plasma plume. The characteristics of both depend on physical properties of target material, environmental conditions, and laser parameters (e.g. wavelength, pulse duration, energy, beam diameter) etc. It has been shown for numerous metals and their alloys that plasma threshold fluence, plasma threshold energy, ablation efficiency, ablation yield, angular distribution of laser produced plasma (LPP) ions, etc. are a unique function of the Debye-Waller thermal parameter B or the mean-square amplitude of atomic vibration of the target material for given experimental conditions. The FWHM of the angular distribution of LPP ions, ablation yield, and ablation efficiency increase whereas plasma threshold fluence and plasma threshold energy decrease as B-factor of the target material increases

  16. Mechanism and Natural Course of Tumor Involution in Hepatocellular Carcinoma Following Transarterial Ethanol Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Simon Chun Ho, E-mail: simonyu@cuhk.edu.hk; Lau, Tiffany Wing Wa; Tang, Peggy; Chan, Stephen Ka Chi; Chu, Charmant Cheuk Man; Hui, Joyce Wai Yi [The Chinese University of Hong Kong, Department of Imaging and Interventional Radiology, Prince of Wales Hospital (Hong Kong); Lee, Kit Fai [Prince of Wales Hospital, Department of Surgery (Hong Kong); Chan, Anthony [The Chinese University of Hong Kong, Department of Anatomical and Cellular Pathology (Hong Kong)

    2016-08-15

    PurposeTo evaluate the microvascular distribution of lipiodol–ethanol, the histological change of the tumor lesion, and the status of tumor involution over time in hepatocellular carcinoma (HCC) following transarterial ethanol ablation (TEA), in lesions that showed CT evidence of complete tumor response.Materials and methodsPatients with unresectable HCC were treated (183 patients, 242 lesions) with TEA using lipiodol–ethanol mixture (LEM) mixed in 2:1 ratio by volume and followed with CT at 3-month intervals for a median of 14.1 months. Liver tumors (n = 131) that showed CT evidence of complete tumor response, defined as the absence of any enhancing tumor throughout the follow-up period, were included. The surgical specimens of five patients who subsequently received partial hepatectomy were available for histological assessment. The microvascular distribution of LEM and the degree of tumor necrosis were analyzed. Tumor involution over time was assessed with CT in lesions that showed complete response.ResultsLipid stain revealed lipiodol infiltration throughout arterioles, intratumoral sinusoidal spaces, tumor capsule, and peritumoral portal venules. Complete tumor necrosis (100 %) occurred in all 5 surgical specimens. The median (IQR) percentage tumor volume compared to baseline volumes at 12, 36, and 60 months was 32 % (23.5–52.5 %), 22 % (8–31 %), and 13.5 % (6–21.5 %), respectively.ConclusionIntrahepatic HCC lesion that showed CT evidence of complete tumor response following TEA is associated with histological evidence of LEM infiltration throughout the intratumoral and peritumoral vasculature and complete tumor necrosis, as well as sustained reduction in tumor volume over time.

  17. A Spectrum of Nerve Injury after Thermal Ablation: A Report of Four Cases and Review of the Literature

    Energy Technology Data Exchange (ETDEWEB)

    Philip, Asher [The University of Texas Medical School (United States); Gupta, Sanjay, E-mail: sgupta@mdanderson.org; Ahrar, Kamran, E-mail: kahrar@mdanderson.org; Tam, Alda L., E-mail: alda.tam@di.mdacc.tmc.edu [The University of Texas, MD Anderson Cancer Center, Department of Diagnostic Radiology, Section of Interventional Radiology (United States)

    2013-10-15

    Thermal ablation is an accepted alternative for the palliation of pain from bone metastases. Although rare, neurologic complications after thermal ablation have been reported. We present four cases, including two cases of rapid reversal of postcryoablation neurapraxia after the administration of steroid therapy, and review the literature.

  18. An Approximate Ablative Thermal Protection System Sizing Tool for Entry System Design

    Science.gov (United States)

    Dec, John A.; Braun, Robert D.

    2006-01-01

    A computer tool to perform entry vehicle ablative thermal protection systems sizing has been developed. Two options for calculating the thermal response are incorporated into the tool. One, an industry-standard, high-fidelity ablation and thermal response program was integrated into the tool, making use of simulated trajectory data to calculate its boundary conditions at the ablating surface. Second, an approximate method that uses heat of ablation data to estimate heat shield recession during entry has been coupled to a one-dimensional finite-difference calculation that calculates the in-depth thermal response. The in-depth solution accounts for material decomposition, but does not account for pyrolysis gas energy absorption through the material. Engineering correlations are used to estimate stagnation point convective and radiative heating as a function of time. The sizing tool calculates recovery enthalpy, wall enthalpy, surface pressure, and heat transfer coefficient. Verification of this tool is performed by comparison to past thermal protection system sizings for the Mars Pathfinder and Stardust entry systems and calculations are performed for an Apollo capsule entering the atmosphere at lunar and Mars return speeds.

  19. On a computational study for investigating acoustic streaming and heating during focused ultrasound ablation of liver tumor

    International Nuclear Information System (INIS)

    Solovchuk, Maxim A.; Sheu, Tony W.H.; Thiriet, Marc; Lin, Win-Li

    2013-01-01

    The influences of blood vessels and focused location on temperature distribution during high-intensity focused ultrasound (HIFU) ablation of liver tumors are studied numerically. A three-dimensional acoustics-thermal-fluid coupling model is employed to compute the temperature field in the hepatic cancerous region. The model construction is based on the linear Westervelt and bioheat equations as well as the nonlinear Navier–Stokes equations for the liver parenchyma and blood vessels. The effect of acoustic streaming is also taken into account in the present HIFU simulation study. Different blood vessel diameters and focal point locations were investigated. We found from this three-dimensional numerical study that in large blood vessels both the convective cooling and acoustic streaming can considerably change the temperature field and the thermal lesion near blood vessels. If the blood vessel is located within the beam width, both acoustic streaming and blood flow cooling effects should be addressed. The temperature rise on the blood vessel wall generated by a 1.0 MHz focused ultrasound transducer with the focal intensity 327 W/cm 2 was 54% lower when acoustic streaming effect was taken into account. Subject to the applied acoustic power the streaming velocity in a 3 mm blood vessel is 12 cm/s. Thirty percent of the necrosed volume can be reduced, when taking into account the acoustic streaming effect. -- Highlights: • 3D three-field coupling physical model for focused ultrasound tumor ablation is presented. • Acoustic streaming and blood flow cooling effects on ultrasound heating are investigated. • Acoustic streaming can considerably affect the temperature distribution. • The lesion can be reduced by 30% due to the acoustic streaming effect. • Temperature on the blood vessel wall is reduced by 54% due to the acoustic streaming effect

  20. Radiofrequency thermal ablation of benign cystic lesion: an experimental pilot study in a porcine gallbladder model

    International Nuclear Information System (INIS)

    Song, Ho Taek; Rhim, Hyun Chul; Choi, Jung Bin; Oh, Jae Cheon; Cho, On Koo; Koh, Byung Hee; Kim, Yong Soo; Seo, Heung Suk; Joo, Kyung Bin

    2001-01-01

    To determine whether radiofrequency thermal ablation can be used to treat benign cystic lesions in a porcine gallbladder model. This experimental study of radiofrequency thermal ablation involved the use of 15 exvivo porcine gallbladders and 15-G expandable needle electrodes. To investigate optimal temperature parameters, three groups of five were designated according to target temperature:Group A: 70 deg C; Group B: 80 deg C; Group C: 90 deg C. After the target temperature was reached, ablation lasted for one minute. Gallbladder width, height and length were measured before and after ablation , and the estimated volume reduction ratios of the three groups were compared. Whether adjacent liver parenchyma around the gallbladder fossa was ablated by heat conducted from hot bile was also determined, and the thickness of the ablated area of the liver was measured. The volume reduction ratio in Group A, B and C was 42.7%, 41.7% and 42.9%, respectively (ρ>.05). In all 15 cases, gallbladder walls lost their transparency and elasticity at about 70 deg C. In nine of ten cases in Groups B and C, the hepatic capsule around the gallbladder fossa was retracted at about 80 deg C. The mean thickness of liver parenchymal damage adjacent to the gallbladder was 5.4 mm in Group B and 9.8 mm in Group C. In Group A livers, only one case showed minimal gradual parenchymal change. Microscopically, all three groups showed complete coagulation necrosis of the wall. On the basis of this feasibility study, radiofrequency thermal ablation is potentially suitable for the ultrasound-guided treatment of symptomatic cystic lesions including benign hepatic or renal cyst

  1. Prognostic Factors Influencing the Development of an Iatrogenic Pneumothorax for Computed Tomography-Guided Radiofrequency Ablation of Upper Renal Tumor

    International Nuclear Information System (INIS)

    Park, B.K.; Kim, C.K.

    2008-01-01

    Background: Percutaneous radiofrequency (RF) ablation of upper renal tumors is considered a minimally invasive treatment, but this technique may cause pneumothorax. Purpose: To assess retrospectively the prognostic factors influencing the development of iatrogenic pneumothorax for RF ablation of upper renal tumors. Material and Methods: Computed tomography (CT)-guided RF ablation was performed in 24 patients (21 men, three women; age range 31-77 years, mean age 53.3 years) with 28 upper renal tumors. Various factors for pneumothorax-complicated (PC) upper renal tumors and non-pneumothoracic (NP) upper renal tumors were compared during RF ablation to determine which of the factors were involved in the development of pneumothorax. Results: Among 28 upper renal tumors in 24 patients, a pneumothorax occurred accidentally in six patients with eight tumors and intentionally in two patients with two tumors. This complication was treated with conservative management, instead of tube drainage. PC upper renal tumors had shorter distance from the lung or from the costophrenic line to the tumor, a larger angle between the costophrenic line and the tumor, and a higher incidence of intervening lung tissue than NP upper renal tumors (P<0.01). Intervening lung tissue was more frequently detected on CT images obtained with the patient in the prone position than on CT images obtained with the patient in the supine position. Conclusion: The presence of intervening lung tissue and the close proximity between an upper renal tumor and the lung are high risk factors for developing an iatrogenic pneumothorax. Pre-ablation CT scan should be performed in the prone position to exactly evaluate intervening lung tissue

  2. Interest of Electrostimulation of Peripheral Motor Nerves during Percutaneous Thermal Ablation

    International Nuclear Information System (INIS)

    Tsoumakidou, Georgia; Garnon, Julien; Ramamurthy, Nitin; Buy, Xavier; Gangi, Afshin

    2013-01-01

    Purpose: We present our experience of utilizing peripheral nerve electrostimulation as a complementary monitoring technique during percutaneous thermal ablation procedures; and we highlight its utility and feasibility in the prevention of iatrogenic neurologic thermal injury. Methods: Peripheral motor nerve electrostimulation was performed in 12 patients undergoing percutaneous image-guided thermal ablations of spinal/pelvic lesions in close proximity to the spinal cord and nerve roots. Electrostimulation was used in addition to existing insulation (active warming/cooling with hydrodissection, passive insulation with CO 2 insufflation) and temperature monitoring (thermocouples) techniques. Impending neurologic deficit was defined as a visual reduction of muscle response or need for a stronger electric current to evoke muscle contraction, compared with baseline. Results: Significant reduction of the muscle response to electrostimulation was observed in three patients during the ablation, necessitating temporary interruption, followed by injection of warm/cool saline. This resulted in complete recovery of the muscle response in two cases, while for the third patient the response did not improve and the procedure was terminated. No patient experienced postoperative motor deficit. Conclusion: Peripheral motor nerve electrostimulation is a simple, easily accessible technique allowing early detection of impending neurologic injury during percutaneous image-guided thermal ablation. It complements existing monitoring techniques and provides a functional assessment along the whole length of the nerve

  3. Interest of Electrostimulation of Peripheral Motor Nerves during Percutaneous Thermal Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Tsoumakidou, Georgia, E-mail: gtsoumakidou@yahoo.com; Garnon, Julien, E-mail: juliengarnon@gmail.com; Ramamurthy, Nitin, E-mail: nitin_ramamurthy@hotmail.com; Buy, Xavier, E-mail: xbuy@ymail.com; Gangi, Afshin, E-mail: gangi@unistra.fr [University Hospital of Strasbourg (France)

    2013-12-15

    Purpose: We present our experience of utilizing peripheral nerve electrostimulation as a complementary monitoring technique during percutaneous thermal ablation procedures; and we highlight its utility and feasibility in the prevention of iatrogenic neurologic thermal injury. Methods: Peripheral motor nerve electrostimulation was performed in 12 patients undergoing percutaneous image-guided thermal ablations of spinal/pelvic lesions in close proximity to the spinal cord and nerve roots. Electrostimulation was used in addition to existing insulation (active warming/cooling with hydrodissection, passive insulation with CO{sub 2} insufflation) and temperature monitoring (thermocouples) techniques. Impending neurologic deficit was defined as a visual reduction of muscle response or need for a stronger electric current to evoke muscle contraction, compared with baseline. Results: Significant reduction of the muscle response to electrostimulation was observed in three patients during the ablation, necessitating temporary interruption, followed by injection of warm/cool saline. This resulted in complete recovery of the muscle response in two cases, while for the third patient the response did not improve and the procedure was terminated. No patient experienced postoperative motor deficit. Conclusion: Peripheral motor nerve electrostimulation is a simple, easily accessible technique allowing early detection of impending neurologic injury during percutaneous image-guided thermal ablation. It complements existing monitoring techniques and provides a functional assessment along the whole length of the nerve.

  4. Novel Percutaneous Radiofrequency Ablation of Portal Vein Tumor Thrombus: Safety and Feasibility

    Energy Technology Data Exchange (ETDEWEB)

    Mizandari, Malkhaz [High Technology Medical Center, Tbilisi State Medical University (Georgia); Ao, Guokun [The 309 Hospital of People' s Liberation Army, Department on Oncology (China); Zhang Yaojun; Feng Xi [Imperial College London, Department of Surgery and Cancer (United Kingdom); Shen Qiang [The First Minimally Invasive Department of Eastern Hepatobiliary Surgery Hospital (China); Chen Minshan [Cancer Centre of Sun Yat-Sen University, Department of Hepatobiliary Surgery (China); Lau, Wan Yee [Chinese University of Hong Kong, Department of Surgery, Faculty of Medicine (Hong Kong); Nicholls, Joanna; Jiao Long; Habib, Nagy, E-mail: nagy.habib@imperial.ac.uk [Imperial College London, Department of Surgery and Cancer (United Kingdom)

    2013-02-15

    We report our experience of the safety of partial recanalization of the portal vein using a novel endovascular radiofrequency (RF) catheter for portal vein tumor thrombosis. Six patients with liver cancer and tumor thrombus in the portal vein underwent percutaneous intravascular radiofrequency ablation (RFA) using an endovascular bipolar RF device. A 0.035-inch guidewire was introduced into a tributary of the portal vein and through which a 5G guide catheter was introduced into the main portal vein. After manipulation of the guide catheter over the thrombus under digital subtraction angiography, the endovascular RF device was inserted and activated around the thrombus. There were no observed technique specific complications, such as hemorrhage, vessel perforation, or infection. Post-RFA portography showed partial recanalization of portal vein. RFA of portal vein tumor thrombus in patients with hepatocellular carcinoma is technically feasible and warrants further investigation to assess efficacy compared with current recanalization techniques.

  5. Frequency and Risk Factors of Various Complications After Computed Tomography-Guided Radiofrequency Ablation of Lung Tumors

    International Nuclear Information System (INIS)

    Okuma, Tomohisa; Matsuoka, Toshiyuki; Yamamoto, Akira; Oyama, Yoshimasa; Toyoshima, Masami; Nakamura, Kenji; Inoue, Yuichi

    2008-01-01

    Objective. To retrospectively determine the frequency and risk factors of various side effects and complications after percutaneous computed tomography-guided radiofrequency (RF) ablation of lung tumors. Methods. We reviewed and analyzed records of 112 treatment sessions in 57 of our patients (45 men and 12 women) with unresectable lung tumors treated by ablation. Risk factors, including sex, age, tumor diameter, tumor location, history of surgery, presence of pulmonary emphysema, electrode gauge, array diameter, patient position, maximum power output, ablation time, and minimum impedance during ablation, were analyzed using univariate and multivariate analyses. Results. Total rates of side effects and minor and major complications occurred in 17%, 50%, and 8% of treatment sessions, respectively. Side effects, including pain during ablation (46% of sessions) and pleural effusion (13% of sessions), occurred with RF ablation. Minor complications, including pneumothorax not requiring chest tube drainage (30% of sessions), subcutaneous emphysema (16% of sessions), and hemoptysis (9% of sessions) also occurred after the procedure. Regarding major complications, three patients developed fever >38.5 deg. C; three patients developed abscesses; two patients developed pneumothorax requiring chest tube insertion; and one patient had air embolism and was discharged without neurologic deficit. Univariate and multivariate analyses suggested that a lesion located ≤1 cm of the chest wall was significantly related to pain (p < 0.01, hazard index 5.76). Risk factors for pneumothorax increased significantly with previous pulmonary surgery (p < 0.05, hazard index 6.1) and presence of emphysema (p <0.01, hazard index 13.6). Conclusion. The total complication rate for all treatment sessions was 58%, and 25% of patients did not have any complications after RF ablation. Although major complications can occur, RF ablation of lung tumors can be considered a safe and minimally invasive

  6. High-intensity interstitial ultrasound for thermal ablation of focal cancer targets in prostate

    Science.gov (United States)

    Salgaonkar, Vasant A.; Scott, Serena; Kurhanewicz, John; Diederich, Chris J.

    2017-03-01

    Recent advances in image based techniques such as multi-parametric MRI (MP-MRI) can provide precise targeting of focal disease in the prostate. Thermal ablation of such cancer targets while avoiding rectum, urethra, neurovascular bundles (NVB) and sphincter is clinically challenging. The approach described here employs multi-element ultrasound linear arrays designed for transperineal placement within prostate. They consist of independently powered sectored tubular transducers (6.5 - 8.0 MHz) that provide spatial control of energy deposition in angle and length. Volumetric ablation strategies were investigated through patient-specific biothermal models based on Pennes bioheat transfer equation. The acoustic and heat transfer models used here have been validated in several previous simulation and experimental studies. Focal disease sites in prostate were identified through multi-parametric MR images of representative patient cases (n=3). Focal cancer lesions and critical anatomy (prostate, urethra, rectum, bladder, seminal vesicles) were manually segmented (Mimics, Materialise) and converted to 3D finite element meshes (3-Matic, Materialise). The chosen test cases consisted of patients with medium and large sized glands and models of bulk tissue ablation covered volumes in a single quadrant in posterior prostate, hemi-gland targets and "hockey-stick" targets (lesions in three quadrants). Ultrasound applicator placement was determined such that devices were positioned along the prostate periphery while avoiding surrounding anatomy. Transducer sector angles were chosen based on applicator location within limits of fabrication practicability. Thermal models were numerically solved using finite element methods (FEM) in COMSOL Multiphysics. Temperature and thermal dose distributions were calculated to determine treated volumes (> 240 CEM43C, >52 °C) and safety profiles (<10 CEM43C, <45 °C) for nerve, rectal and urethral sparing. Modeling studies indicated that focal

  7. Conformal Ablative Thermal Protection Systems (CA-TPS) for Venus and Saturn Backshells

    Science.gov (United States)

    Beck, R.; Gasch, M.; Stackpoole, M.; Wilder, M.; Boghozian, T.; Chavez-Garcia, J.; Prabhu, Dinesh; Kazemba, Cole D.; Venkatapathy, E.

    2016-01-01

    This poster provides an overview of the work performed to date on the Conformal Ablative TPS (CA-TPS) element of the TPSM project out of GCDP. Under this element, NASA is developing improved ablative TPS materials based on flexible felt for reinforcement rather than rigid reinforcements. By replacing the reinforcements with felt, the resulting materials have much higher strain-to-failure and are much lower in thermal conductivity than their rigid counterparts. These characteristics should allow for larger tile sizes, direct bonding to aeroshells and even lower weight TPS. The conformal phenolic impregnated carbon felt (C-PICA) is a candidate for backshell TPS for both Venus and Saturn entry vehicles.

  8. Replacement of Ablators with Phase-Change Material for Thermal Protection of STS Elements

    Science.gov (United States)

    Kaul, Raj K.; Stuckey, Irvin; Munafo, Paul M. (Technical Monitor)

    2002-01-01

    As part of the research and development program to develop new Thermal Protection System (TPS) materials for aerospace applications at NASA's Marshall Space Flight Center (MSFC), an experimental study was conducted on a new concept for a non-ablative TPS material. Potential loss of TPS material and ablation by-products from the External Tank (ET) or Solid Rocket Booster (SRB) during Shuttle flight with the related Orbiter tile damage necessitates development of a non-ablative thermal protection system. The new Thermal Management Coating (TMC) consists of phase-change material encapsulated in micro spheres and a two-part resin system to adhere the coating to the structure material. The TMC uses a phase-change material to dissipate the heat produced during supersonic flight rather than an ablative material. This new material absorbs energy as it goes through a phase change during the heating portion of the flight profile and then the energy is slowly released as the phase-change material cools and returns to its solid state inside the micro spheres. The coating was subjected to different test conditions simulating design flight environments at the NASA/MSFC Improved Hot Gas Facility (IHGF) to study its performance.

  9. Time-resolved investigations of the non-thermal ablation process of graphite induced by femtosecond laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Kalupka, C., E-mail: christian.kalupka@llt.rwth-aachen.de; Finger, J. [Chair for Laser Technology LLT, RWTH Aachen University, Aachen 52074 (Germany); Reininghaus, M. [Chair for Laser Technology LLT, RWTH Aachen University, Aachen 52074 (Germany); Fraunhofer Institute for Laser Technology ILT, Steinbachstraße 15, Aachen 52074 (Germany)

    2016-04-21

    We report on the in-situ analysis of the ablation dynamics of the, so-called, laser induced non-thermal ablation process of graphite. A highly oriented pyrolytic graphite is excited by femtosecond laser pulses with fluences below the classic thermal ablation threshold. The ablation dynamics are investigated by axial pump-probe reflection measurements, transversal pump-probe shadowgraphy, and time-resolved transversal emission photography. The combination of the applied analysis methods allows for a continuous and detailed time-resolved observation of the non-thermal ablation dynamics from several picoseconds up to 180 ns. Formation of large, μm-sized particles takes place within the first 3.5 ns after irradiation. The following propagation of ablation products and the shock wave front are tracked by transversal shadowgraphy up to 16 ns. The comparison of ablation dynamics of different fluences by emission photography reveals thermal ablation products even for non-thermal fluences.

  10. CT-Guided Microwave Ablation of 45 Renal Tumors: Analysis of Procedure Complexity Utilizing a Percutaneous Renal Ablation Complexity Scoring System.

    Science.gov (United States)

    Mansilla, Alberto V; Bivins, Eugene E; Contreras, Francisco; Hernandez, Manuel A; Kohler, Nathan; Pepe, Julie W

    2017-02-01

    To develop a scoring system that stratifies complexity of percutaneous ablation of renal tumors. Analysis was performed of 36 consecutive patients (mean age, 64 y; range, 30-89 y) who underwent CT-guided microwave (MW) ablation of 45 renal tumors (mean tumor diameter, 2.4 cm; range, 1.2-4.0 cm). Technical success and effectiveness were determined based on intraprocedural and follow-up imaging studies. The RENAL score and the proposed percutaneous renal ablation complexity (P-RAC) score were calculated for each tumor. Technical success was 93.3% (n = 42). Biopsy of 38 of 45 renal tumors revealed 23 renal cell carcinomas. Median follow-up period was 9.7 months (range, 2.9-46.8 months). There were no tumor recurrences. One major complication, ureteropelvic junction stricture, occurred (2.6%). The P-RAC score was found to differ statistically from the RENAL score (t = 3.754, df = 44, P = .001). A positive correlation was found between the P-RAC score and number of antenna insertions (r = .378, n = 45, P = .011) and procedure duration (r = .328, n = 45, P = .028). No correlation was found between the RENAL score and number of MW antenna insertions (r = .110, n = 45, P = .472) or procedure duration (r = .263, n = 45, P = .081). Hydrodissection was significantly more common in the P-RAC high-complexity category than in low-complexity category (χ 2 = 12.073, df = 2, P = .002). The P-RAC score may be useful in stratifying percutaneous renal ablation complexity. Further studies with larger sample sizes are necessary to validate the P-RAC score and to determine if it can predict risk of complications. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.

  11. Intrabiliary growth of recurrent tumor after percutaneous RF ablation for treating liver metastasis from colon cancer: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youn Kyung; Kim, Seung Kwon; Hong, Hyun Pyo [Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2007-12-15

    A 64-year-old man who underwent right hemicolectomy 3.5 years ago for ascending colon cancer and then RF ablation for two metastatic nodules in the liver was admitted to our hospital with a new metastatic nodule in the S6/7 segment of the liver. The CT scan showed a low attenuating metastatic nodule 2.2 cm in diameter in the S6/7 segment of the liver, and the liver showed peripheral bile duct dilatation. This nodule was treated with percutaneous RF ablation. A follow-up CT seven months after RF ablation showed the presence of a viable tumor in the RF ablation zone, with tumor extension along the dilated bile duct. These findings were confirmed on the resected specimen.

  12. CBCT-Guided Rapid Arc for stereotactic ablative radiotherapy (SABR) in lung tumors

    Energy Technology Data Exchange (ETDEWEB)

    Fandino, J. M.; Silva, M. C.; Izquierdo, P.; Candal, A.; Diaz, I.; Fernandez, C.; Gesto, C.; Poncet, M.; Soto, M.; Triana, G.; Losada, C.; Marino, A.

    2013-07-01

    Stereotactic ablative radiotherapy has emerged as a standard treatment option for stage I non-small cell lung cancer in patients unfit for surgery, or who refuse surgery. An increasing number of prospective phase I/II trials, as well as large single and multicenter studies have reported local control rates to be in excess of 85% for early stage non-small cell lung cancer. Volumetric arc therapy RapidArc with tumor-based image guidance technique will be presented as well as our preliminary observations. (Author)

  13. Asian EUS Cup-05: Successful management of peripancreatic tumors by endoscopic ultrasound-guided radiofrequency ablation

    OpenAIRE

    Oh, Dongwook; Seo, Dong Wan

    2017-01-01

    Background: Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) could be used as an effective alternative treatment for peripancreatic tumor. Herein, we reported a case of adrenal adenoma which was treated by EUS-RFA. Case Report: A 38-year-old woman presented with ?moon face,? ?buffalo hump,? and weight gain of 9 kg in 12 months. Initial contrast-enhanced abdominal computed tomography showed a 2.8 cm left adrenal mass, and the patient was diagnosed with Cushing?s syndrome due to l...

  14. The thermal and mechanical properties of a low-density glass-fiber-reinforced elastomeric ablation material

    Science.gov (United States)

    Engelke, W. T.; Robertson, R. W.; Bush, A. L.; Pears, C. D.

    1974-01-01

    An evaluation of the thermal and mechanical properties was performed on a molded low-density elastomeric ablation material designated as Material B. Both the virgin and charred states were examined to provide meaningful inputs to the design of a thermal protection system. Chars representative of the flight chars formed during ablation were prepared in a laboratory furnace from 600 K to 1700 K and properties of effective thermal conductivity, heat capacity, porosity and permeability were determined on the furnace chars formed at various temperature levels within the range. This provided a boxing of the data which will enable the prediction of the transient response of the material during flight ablation.

  15. Coupled Aeroheating and Ablative Thermal Response Simulation Tool

    Data.gov (United States)

    National Aeronautics and Space Administration — The thermal protection system (TPS) performance requirements for atmospheric entry vehicles on current and future NASA missions preclude the use of heritage reusable...

  16. NDE for Ablative Thermal Protection Systems, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This program addresses the need for non-destructive evaluation (NDE) methods for quality assessment and defect evaluation of thermal protection systems (TPS),...

  17. NDE for Ablative Thermal Protection Systems, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This program addresses the need for non-destructive evaluation (NDE) methods for quality assessment and defect evaluation of thermal protection systems (TPS). Novel...

  18. Development of a high-field MR-guided HIFU setup for thermal and mechanical ablation methods in small animals

    NARCIS (Netherlands)

    Hoogenboom, M.; Amerongen, M.J. van; Eikelenboom, D.C.; Wassink, M.; Brok, M.H. den; Hulsbergen-van de Kaa, C.A.; Dumont, E.; Adema, G.J.; Heerschap, A.; Futterer, J.J.

    2015-01-01

    BACKGROUND: Thermal and mechanical high intensity focused ultrasound (HIFU) ablation techniques are in development for non-invasive treatment of cancer. However, knowledge of in vivo histopathologic and immunologic reactions after HIFU ablation is still limited. This study aims to create a setup for

  19. Assessment of liver tumor response by high-field (3 T) MRI after radiofrequency ablation: Short- and mid-term evolution of diffusion parameters within the ablation zone

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Tri-Linh, E-mail: tluonmac@gmail.com [Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Rue du Bugnon 46, 1011 Lausanne (Switzerland); Becce, Fabio; Bize, Pierre; Denys, Alban; Meuli, Reto; Schmidt, Sabine [Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Rue du Bugnon 46, 1011 Lausanne (Switzerland)

    2012-09-15

    Purpose: To compare the apparent diffusion coefficient (ADC) values of malignant liver lesions on diffusion-weighted MRI (DWI) before and after successful radiofrequency ablation (RF ablation). Materials and methods: Thirty-two patients with 43 malignant liver lesions (23/20: metastases/hepatocellular carcinomas (HCC)) underwent liver MRI (3.0 T) before (<1 month) and after RF ablation (at 1, 3 and 6 months) using T2-, gadolinium-enhanced T1- and DWI-weighted MR sequences. Jointly, two radiologists prospectively measured ADCs for each lesion by means of two different regions of interest (ROIs), first including the whole lesion and secondly the area with the visibly most restricted diffusion (MRDA) on ADC map. Changes of ADCs were evaluated with ANOVA and Dunnett tests. Results: Thirty-one patients were successfully treated, while one patient was excluded due to focal recurrence. In metastases (n = 22), the ADC in the whole lesion and in MRDA showed an up-and-down evolution. In HCC (n = 20), the evolution of ADC was more complex, but with significantly higher values (p = 0.013) at 1 and 6 months after RF ablation. Conclusion: The ADC values of malignant liver lesions successfully treated by RF ablation show a predictable evolution and may help radiologists to monitor tumor response after treatment.

  20. An in-vitro animal experiment on metal implants’ thermal effect on radiofrequency ablation

    Science.gov (United States)

    2013-01-01

    Background To explore metal implants’ thermal effect on radiofrequency ablation (RFA) and ascertain distance-thermal relationship between the metal implants and radiofrequency (RF) electrode. Methods Metal implants models were established in seven in-vitro porcine livers using silver clips or 125I seeds. RFA were conducted centering the RF electrode axis1 cm away from them, with one side containing a metal implants model the test group and the other side the control group. The thermometric needles were used to measure multi-point temperatures in order to compare the time-distance-temperature difference between the two groups. The gross scopes of the ablation of the two groups were measured and the tissues were analyzed for microscopic histology. Results At the ablation times of 8, 12, and 15 min, the average multi-point temperatures of the test group and the control group were 48.2±18.07°C, 51.5±19.57°C, 54.6±19.75°C, and 48.6±17.69°C, 52.2±19.73°C, 54.9±19.24°C, respectively, and the differences were not statistically significant (n=126, P>0.05). At the ablation times of 12 and 15 min, the ablation scopes of the test group and the control group were (horizontal/longitudinal diameter) 1.55/3.48 cm, 1.89/3.72 cm, and 1.56/3.48 cm, 1.89/3.72 cm, respectively, and the differences were not statistically significant (n=14, P>0.05). The two groups had the same manifestations in microscopy. Conclusions Metal implants do not cause significant thermal effect on RFA. PMID:23799942

  1. Radiofrequency ablation of hepatic tumors: simulation, planning, and contribution of virtual reality and haptics.

    Science.gov (United States)

    Villard, Caroline; Soler, Luc; Gangi, Afshin

    2005-08-01

    For radiofrequency ablation (RFA) of liver tumors, evaluation of vascular architecture, post-RFA necrosis prediction, and the choice of a suitable needle placement strategy using conventional radiological techniques remain difficult. In an attempt to enhance the safety of RFA, a 3D simulator, treatment planning, and training tool, that simulates the insertion of the needle, the necrosis of the treated area, and proposes an optimal needle placement, has been developed. The 3D scenes are automatically reconstructed from enhanced spiral CT scans. The simulator takes into account the cooling effect of local vessels greater than 3 mm in diameter, making necrosis shapes more realistic. Optimal needle positioning can be automatically generated by the software to produce complete destruction of the tumor, with maximum respect of the healthy liver and of all major structures to avoid. We also studied how the use of virtual reality and haptic devices are valuable to make simulation and training realistic and effective.

  2. A metastatic adrenal tumor from a hepatocellular carcinoma: combination therapy with transarterial chemoembolization and radiofrequency ablation

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hyun Jin; Cho, Yun Ku; Ahn, Yong Sik; Kim, Mi Young [Seoul Veterans Hospital, Seoul (Korea, Republic of)

    2007-07-15

    The adrenal gland is the second most common site of metastasis from a hepatocellular carcinoma (HCC). Radiofrequency ablation (RFA) for these tumors has been reported to be a potentially effective alternative to an adrenalectomy, especially for inoperable patients. However, for intermediate or large adrenal tumors, combination therapy of transarterial chemoembolization (TACE) and RFA can be attempted as it may reduce the heat sink effect. A 74-year-old patient presented with abdominal discomfort. Abdominal CT images revealed a 5.0 cm sized right adrenal mass. A percutaneous biopsy of the adrenal mass revealed a metastatic hepatocellular carcinoma. TACE was performed on the adrenal mass. However, a one-month follow-up CT image revealed a residual viable tumor. RFA was performed for the adrenal tumor six weeks after the TACE. No procedure-related major complications were noted. The serum alpha-fetoprotein level had also been normalized after the treatment, and 10-month follow-up CT images showed no definite evidence of viable adrenal tumor.

  3. Requirements and prototype for supporting the planning of patient specific thermal ablation interventions

    International Nuclear Information System (INIS)

    Schramm, W.

    2010-01-01

    Background Thermal ablation is the process of destroying pathological tissue by either high temperatures of approximately 105 o C as achieved in radiofrequency ablation or low temperatures of approximately - 40 o C as used in cryotherapy. Ablations are widely used in clinical practice and provide a safe and generally well tolerated minimal invasive treatment if surgery is not an option. Thermal ablations are usually performed under image guidance, either by ultrasound, CT or MR. Even though ablations are widely used, very little textbook knowledge is available. Because of the treatment complexity there is a need for a well defined process which can be followed by an experienced radiologist as well as an inexperienced one. There is also a need for a planning platform which is capable of supporting the physician in planning the intervention on the basis of the patient's anatomy. For additional benefit this platform should also provide the means for estimating the final coagulation zone by simulations based on the patient's anatomy. The most widely used method to simulate the extend of a coagulation zone is by the usage of finite element analysis (FEA). FEA uses a defined geometry with the physical properties of the tissue and the ablation modality to create a model which can then be solved to make estimations about the extend of the final coagulation zone. Method and Results To deal with the problem of ablation knowledge being only available in distributed form, a workflow was abstracted and translated into diagrams. These workflow diagrams visualize the required steps and decisions when performing thermal ablations. The workflow is split into a planning, applicator placement, ablation and result evaluation phase. The information gained from this knowledge is then used to define the requirements for a platform which is capable of helping the physician when performing the ablation. In the next step I examined the possibility to increase an ablation's coagulation zone

  4. Combined Therapies for the Treatment of Technically Unresectable Liver Malignancies: Bland Embolization and Radiofrequency Thermal Ablation within the Same Session

    International Nuclear Information System (INIS)

    Bonomo, Guido; Della Vigna, Paolo; Monfardini, Lorenzo; Orgera, Gianluigi; Chiappa, Antonio; Bianchi, Paolo Pietro; Zampino, Maria Giulia; Orsi, Franco

    2012-01-01

    Purpose: This retrospective study evaluated the feasibility, efficacy, and safety of combining transcatheter arterial embolization (TAE) with radiofrequency thermal ablation (RFA) in a single session for the treatment of technically unresectable liver-only malignancies. Methods: From May 2006 to January 2011, a total of 30 patients affected by liver metastases with single or multiple unresectable liver-only lesions underwent a combined treatment with TAE followed by RFA in the same session, for a total of 36 treated lesions. Patients were extrapolated from a cohort of patients discussed within the weekly institutional tumor board. TAE was performed by using 100 μm microspheres; RFA was performed immediately after TAE by positioning the electrode needle via ultrasound and/or computed tomographic guidance. Local tumor responses and procedure-related complications were evaluated. Results: Completion of both procedures was obtained in all patients for all 36 lesions. Liver lesions had a maximum axial diameter ranging 16–59 mm. Postintervention unenhanced ablated areas ranged 28–104 mm in maximum axial diameter. Safety margins ranged 1–30.5 mm. Complete response, defined as complete devascularization at computed tomography, was obtained in all treated lesions for a maximum period of 12 months. Tumor relapse was observed in one patient at 12 months. Sixteen patients developed new liver lesions or progressive systemic disease during follow-up. Nine patients were still disease-free. Seven patients died as a result of systemic progressive disease. One major treatment-related complication was observed. Conclusions: In patients with technically unresectable liver-only malignancies, single-session combined TAE-RFA is an effective and safe treatment.

  5. Gold Nanoparticles as a Photothermal Agent in Cancer Therapy: The Thermal Ablation Characteristic Length

    Directory of Open Access Journals (Sweden)

    Thomas Grosges

    2018-05-01

    Full Text Available In cancer therapy, the thermal ablation of diseased cells by embedded nanoparticles is one of the known therapies. It is based on the absorption of the energy of the illuminating laser by nanoparticles. The resulting heating of nanoparticles kills the cell where these photothermal agents are embedded. One of the main constraints of this therapy is preserving the surrounding healthy cells. Therefore, two parameters are of interest. The first one is the thermal ablation characteristic length, which corresponds to an action distance around the nanoparticles for which the temperature exceeds the ablation threshold. This critical geometric parameter is related to the expected conservation of the body temperature in the surroundings of the diseased cell. The second parameter is the temperature that should be reached to achieve active thermal agents. The temperature depends on the power of the illuminating laser, on the size of nanoparticles and on their physical properties. The purpose of this paper is to propose behavior laws under the constraints of both the body temperature at the boundary of the cell to preserve surrounding cells and an acceptable range of temperature in the target cell. The behavior laws are deduced from the finite element method, which is able to model aggregates of nanoparticles. We deduce sensitivities to the laser power and to the particle size. We show that the tuning of the temperature elevation and of the distance of action of a single nanoparticle is not significantly affected by variations of the particle size and of the laser power. Aggregates of nanoparticles are much more efficient, but represent a potential risk to the surrounding cells. Fortunately, by tuning the laser power, the thermal ablation characteristic length can be controlled.

  6. Percutaneous Lung Thermal Ablation of Non-surgical Clinical N0 Non-small Cell Lung Cancer: Results of Eight Years’ Experience in 87 Patients from Two Centers

    International Nuclear Information System (INIS)

    Palussiere, Jean; Lagarde, Philippe; Aupérin, Anne; Deschamps, Frédéric; Chomy, François; Baere, Thierry de

    2015-01-01

    PurposeTo evaluate the survival outcomes of percutaneous thermal ablation (RFA + microwaves) for patients presenting N0 non-small-cell lung cancer (NSCLC) ineligible for surgery.Materials and MethodsEighty-seven patients from two comprehensive cancer centers were included. Eighty-two patients were treated with RFA electrodes and five with microwave antenna. Overall survival (OS) and disease-free survival (DFS) were estimated and predictive factors of local tumor progression, OS and DFS identified and compared by univariate and multivariate analysesResultsMedian follow-up was 30.5 months (interquartile range 16.7–51) and tumor size was 21 mm (range 10–54 mm). Treatment was incomplete for 14 patients with a local tumor progression of 11.5, 18.3, and 21.1 % at 1, 2, and 3 years, respectively. Two patients presented with neurological (grade III or IV) complications, and one died of respiratory and multivisceral failure as a result of the procedure at 29 days. In univariate analysis, increasing tumor size (P = 0.003) was the only predictive factor related to risk of local tumor progression. 5-year OS and DFS were 58.1 and 27.9 %, respectively. Sex (P = 0.044), pathology (P = 0.032), and tumor size >2 cm (P = 0.046) were prognostic factors for DFS. In multivariate analysis, pathology (P = 0.033) and tumor size >2 cm (P = 0.032) were independent prognostic factors for DFS.ConclusionsOversized and overlapping ablation of N0 NSCLC was well tolerated, effective, with few local tumor progressions, even over long-term follow-up. Increasing tumor size was the main prognostic factor linked to OS, DFS, and local tumor progression

  7. Percutaneous Lung Thermal Ablation of Non-surgical Clinical N0 Non-small Cell Lung Cancer: Results of Eight Years’ Experience in 87 Patients from Two Centers

    Energy Technology Data Exchange (ETDEWEB)

    Palussiere, Jean, E-mail: J.Palussiere@bordeaux.unicancer.fr [Institut Bergonié, Comprehensive Cancer Centre, Department of Interventional Radiology (France); Lagarde, Philippe, E-mail: P.Lagarde@bordeaux.unicancer.fr [Institut Bergonié, Comprehensive Cancer Center, Radiation Oncology Department (France); Aupérin, Anne, E-mail: auperin@igr.fr [Institut Gustave-Roussy, Unit of Biostatistics and Epidemiology (France); Deschamps, Frédéric, E-mail: frederic.deschamps@igr.fr [Institut Gustave-Roussy, Department of Interventional Radiology (France); Chomy, François, E-mail: F.Chomy@bordeaux.unicancer.fr [Institut Bergonié, Comprehensive Cancer Center, Department of medical oncology (France); Baere, Thierry de, E-mail: debaere@igr.fr [Institut Gustave-Roussy, Department of Interventional Radiology (France)

    2015-02-15

    PurposeTo evaluate the survival outcomes of percutaneous thermal ablation (RFA + microwaves) for patients presenting N0 non-small-cell lung cancer (NSCLC) ineligible for surgery.Materials and MethodsEighty-seven patients from two comprehensive cancer centers were included. Eighty-two patients were treated with RFA electrodes and five with microwave antenna. Overall survival (OS) and disease-free survival (DFS) were estimated and predictive factors of local tumor progression, OS and DFS identified and compared by univariate and multivariate analysesResultsMedian follow-up was 30.5 months (interquartile range 16.7–51) and tumor size was 21 mm (range 10–54 mm). Treatment was incomplete for 14 patients with a local tumor progression of 11.5, 18.3, and 21.1 % at 1, 2, and 3 years, respectively. Two patients presented with neurological (grade III or IV) complications, and one died of respiratory and multivisceral failure as a result of the procedure at 29 days. In univariate analysis, increasing tumor size (P = 0.003) was the only predictive factor related to risk of local tumor progression. 5-year OS and DFS were 58.1 and 27.9 %, respectively. Sex (P = 0.044), pathology (P = 0.032), and tumor size >2 cm (P = 0.046) were prognostic factors for DFS. In multivariate analysis, pathology (P = 0.033) and tumor size >2 cm (P = 0.032) were independent prognostic factors for DFS.ConclusionsOversized and overlapping ablation of N0 NSCLC was well tolerated, effective, with few local tumor progressions, even over long-term follow-up. Increasing tumor size was the main prognostic factor linked to OS, DFS, and local tumor progression.

  8. Terminology and reporting criteria for radiofrequency ablation of tumors in the scientific literature: Systematic review of compliance with reporting standards

    International Nuclear Information System (INIS)

    Kang, Tae Wook; Rhim, Hyun Chul; Lee, Min Woo; Kim, Young Sun; Choi, Dongil; Lim, Hyo Keun

    2014-01-01

    To perform a systematic review of compliance with standardized terminology and reporting criteria for radiofrequency (RF) tumor ablation, proposed by the International Working Group on Image-Guided Tumor Ablation in 2003, in the published reports. Literature search in the PubMed database was performed using index keywords, PubMed limit system, and eligibility criteria. The entire content of each article was reviewed to assess the terminology used for procedure terms, imaging findings, therapeutic efficacy, follow-up, and complications. Accuracy of the terminology and the use of alternative terms instead of standard terminology were analyzed. In addition, disparities in accuracy of terminology in articles according to the medical specialty and the type of radiology journal were evaluated. Among the articles (n = 308) included in this study, the accuracy of the terms 'procedure or session', 'treatment', 'index tumor', 'ablation zone', 'technical success', 'primary technique effectiveness rate', 'secondary technique effectiveness rate', 'local tumor progression', 'major complication', and 'minor complication' was 97% (298/307), 97% (291/300), 8% (25/307), 65% (103/159), 55% (52/94), 33% (42/129), 94% (17/18), 45% (88/195), 99% (79/80), and 100% (77/77), respectively. The overall accuracy of each term showed a tendency to improve over the years. The most commonly used alternative terms for 'technical success' and 'local tumor progression' were 'complete ablation' and 'local (tumor) recurrence', respectively. The accuracy of terminology in articles published in radiology journals was significantly greater than that of terminology in articles published in non-radiology journals, especially in Radiology and The Journal of Vascular and Interventional Radiology. The proposal for standardization of terminology and reporting criteria for RF tumor ablation has been gaining support according to the recently published scientific reports, especially in the field of radiology

  9. Terminology and reporting criteria for radiofrequency ablation of tumors in the scientific literature: systematic review of compliance with reporting standards.

    Science.gov (United States)

    Kang, Tae Wook; Rhim, Hyunchul; Lee, Min Woo; Kim, Young-sun; Choi, Dongil; Lim, Hyo Keun

    2014-01-01

    To perform a systematic review of compliance with standardized terminology and reporting criteria for radiofrequency (RF) tumor ablation, proposed by the International Working Group on Image-Guided Tumor Ablation in 2003, in the published reports. Literature search in the PubMed database was performed using index keywords, PubMed limit system, and eligibility criteria. The entire content of each article was reviewed to assess the terminology used for procedure terms, imaging findings, therapeutic efficacy, follow-up, and complications. Accuracy of the terminology and the use of alternative terms instead of standard terminology were analyzed. In addition, disparities in accuracy of terminology in articles according to the medical specialty and the type of radiology journal were evaluated. Among the articles (n = 308) included in this study, the accuracy of the terms 'procedure or session', 'treatment', 'index tumor', 'ablation zone', 'technical success', 'primary technique effectiveness rate', 'secondary technique effectiveness rate', 'local tumor progression', 'major complication', and 'minor complication' was 97% (298/307), 97% (291/300), 8% (25/307), 65% (103/159), 55% (52/94), 33% (42/129), 94% (17/18), 45% (88/195), 99% (79/80), and 100% (77/77), respectively. The overall accuracy of each term showed a tendency to improve over the years. The most commonly used alternative terms for 'technical success' and 'local tumor progression' were 'complete ablation' and 'local (tumor) recurrence', respectively. The accuracy of terminology in articles published in radiology journals was significantly greater than that of terminology in articles published in non-radiology journals, especially in Radiology and The Journal of Vascular and Interventional Radiology. The proposal for standardization of terminology and reporting criteria for RF tumor ablation has been gaining support according to the recently published scientific reports, especially in the field of radiology

  10. Is percutaneous microwave ablation of liver tumor safe for patients with renal dysfunction

    International Nuclear Information System (INIS)

    Liu Cun; Wang Yang; Yu Xiaoling; Dong Baowei; Zhou Pei; Ren He; Liang Ping

    2011-01-01

    Purpose: To determine the safety of percutaneous microwave ablation of primary and metastatic liver tumor for patients with renal dysfunction. Materials and methods: Fifty primary and metastatic liver tumors in 23 patients with renal dysfunction were retrospectively reviewed at our institution. Renal function was determined by measuring serum creatinine and serum urea before MWA as baseline, within 1 week and at last follow-up. The mean creatinine was 1.69 ± 0.32 mg/dL, 1.71 ± 0.33 mg/dL, and 1.71 ± 0.26 mg/dL respectively, there was not a statistically significant difference between baseline and at last follow-up (P = 0.26). The mean serum urea was 52.52 ± 6.48 mg/dL, 56.55 ± 14.72 mg/dL, and 57.90 ± 16.39 mg/dL respectively, there was not a statistically significant difference between baseline and within 1 week (P = 0.119), between within baseline and at last follow-up (P = 0.090). At the last follow-up examination, all patients had adequately functioning kidneys and did not require any form of renal replacement therapy. This is a small retrospectively study including highly selected patients treated. Therefore, further study should to determine the safety of percutaneous MWA for patients with renal dysfunction in the future. Conclusions: Percutaneous microwave ablation of primary and metastatic liver tumor is no adverse influence on renal function for patients with renal dysfunction in this preliminary series, which can be a minimally invasive alternative therapy.

  11. Electrical conductivity measurement of excised human metastatic liver tumours before and after thermal ablation.

    Science.gov (United States)

    Haemmerich, Dieter; Schutt, David J; Wright, Andrew W; Webster, John G; Mahvi, David M

    2009-05-01

    We measured the ex vivo electrical conductivity of eight human metastatic liver tumours and six normal liver tissue samples from six patients using the four electrode method over the frequency range 10 Hz to 1 MHz. In addition, in a single patient we measured the electrical conductivity before and after the thermal ablation of normal and tumour tissue. The average conductivity of tumour tissue was significantly higher than normal tissue over the entire frequency range (from 4.11 versus 0.75 mS cm(-1) at 10 Hz, to 5.33 versus 2.88 mS cm(-1) at 1 MHz). We found no significant correlation between tumour size and measured electrical conductivity. While before ablation tumour tissue had considerably higher conductivity than normal tissue, the two had similar conductivity throughout the frequency range after ablation. Tumour tissue conductivity changed by +25% and -7% at 10 Hz and 1 MHz after ablation (0.23-0.29 at 10 Hz, and 0.43-0.40 at 1 MHz), while normal tissue conductivity increased by +270% and +10% at 10 Hz and 1 MHz (0.09-0.32 at 10 Hz and 0.37-0.41 at 1 MHz). These data can potentially be used to differentiate tumour from normal tissue diagnostically.

  12. Microwave Ablation of Lung Tumors Near the Heart: A Retrospective Review of Short-Term Procedural Safety in Ten Patients.

    Science.gov (United States)

    Maxwell, Aaron W P; Healey, Terrance T; Dupuy, Damian E

    2017-09-01

    To evaluate the rate of short-term complications associated with microwave ablation of lung tumors located near the heart. This HIPAA-compliant study was performed with a waiver for informed consent. Patients who underwent microwave ablation of lung tumors located 10 mm or less from the heart were identified by retrospective chart review. Both primary and metastatic tumors were included. Only tumors directly adjacent to one of the four cardiac chambers were included. All patients were treated in a single session using CT guidance with continuous electrocardiographic monitoring. Rates of new-onset arrhythmia and myocardial infarction (MI) within 90 days of the procedure were quantified, and evidence of cardiac or pericardiac injury was assessed for using post-ablation contrast-enhanced chest CT, electrocardiography (EKG), and-when available-echocardiography. Complications were graded using the Common Terminology Criteria for Adverse Events (CTCAE) system. Ten patients (four males, six females; mean age 73.1 ± 9.5 years) met all inclusion criteria. Mean tumor distance from the heart was 3 mm (range, 0-6 mm). New-onset arrhythmia was not observed during or following any of the microwave ablation treatments, and there were no documented 90-day MI events. CTCAE Grade 1 complications were observed by CT in eight patients, most commonly mild focal pericardial thickening. EKG and echocardiography were normal in all patients. No major complications (CTCAE Grade 3 or greater) were observed. Microwave ablation of lung tumors located 10 mm or less from the heart appears to have low associated short-term morbidity and may be appropriate in selected patients.

  13. Photothermal ablation of inflammatory breast cancer tumor emboli using plasmonic gold nanostars

    Directory of Open Access Journals (Sweden)

    Crawford BM

    2017-08-01

    Full Text Available Bridget M Crawford,1,2,* Ronnie L Shammas,3,* Andrew M Fales,1,2 David A Brown,4 Scott T Hollenbeck,4 Tuan Vo-Dinh,1,2,5 Gayathri R Devi6,7 1Fitzpatrick Institute for Photonics, Duke University, 2Department of Biomedical Engineering, Duke University, 3Duke University School of Medicine, 4Department of Surgery, Division of Plastic, Maxillofacial, and Oral Surgery, Duke University Medical Center, 5Department of Chemistry, Duke University, 6Department of Surgery, Division of Surgical Sciences, 7Duke Cancer Institute, Women’s Cancer Program, Duke University School of Medicine, Durham, NC, USA *These authors contributed equally to this work Abstract: Inflammatory breast cancer (IBC is rare, but it is the most aggressive subtype of breast cancer. IBC has a unique presentation of diffuse tumor cell clusters called tumor emboli in the dermis of the chest wall that block lymph vessels causing a painful, erythematous, and edematous breast. Lack of effective therapeutic treatments has caused mortality rates of this cancer to reach 20%–30% in case of women with stage III–IV disease. Plasmonic nanoparticles, via photothermal ablation, are emerging as lead candidates in next-generation cancer treatment for site-specific cell death. Plasmonic gold nanostars (GNS have an extremely large two-photon luminescence cross-section that allows real-time imaging through multiphoton microscopy, as well as superior photothermal conversion efficiency with highly concentrated heating due to its tip-enhanced plasmonic effect. To effectively study the use of GNS as a clinically plausible treatment of IBC, accurate three-dimensional (3D preclinical models are needed. Here, we demonstrate a unique in vitro preclinical model that mimics the tumor emboli structures assumed by IBC in vivo using IBC cell lines SUM149 and SUM190. Furthermore, we demonstrate that GNS are endocytosed into multiple cancer cell lines irrespective of receptor status or drug resistance and that

  14. Stereotactic Ablative Radiation Therapy for Subcentimeter Lung Tumors: Clinical, Dosimetric, and Image Guidance Considerations

    International Nuclear Information System (INIS)

    Louie, Alexander V.; Senan, Suresh; Dahele, Max; Slotman, Ben J.; Verbakel, Wilko F.A.R.

    2014-01-01

    Purpose: Use of stereotactic ablative radiation therapy (SABR) for subcentimeter lung tumors is controversial. We report our outcomes for tumors with diameter ≤1 cm and their visibility on cone beam computed tomography (CBCT) scans and retrospectively evaluate the planned dose using a deterministic dose calculation algorithm (Acuros XB [AXB]). Methods and Materials: We identified subcentimeter tumors from our institutional SABR database. Tumor size was remeasured on an artifact-free phase of the planning 4-dimensional (4D)-CT. Clinical plan doses were generated using either a pencil beam convolution or an anisotropic analytic algorithm (AAA). All AAA plans were recalculated using AXB, and differences among D95 and mean dose for internal target volume (ITV) and planning target volume (PTV) on the average intensity CT dataset, as well as for gross tumor volume (GTV) on the end respiratory phases were reported. For all AAA patients, CBCT scans acquired during each treatment fraction were evaluated for target visibility. Progression-free and overall survival rates were calculated using the Kaplan-Meier method. Results: Thirty-five patients with 37 subcentimeter tumors were eligible for analysis. For the 22 AAA plans recalculated using AXB, Mean D95 ± SD values were 2.2 ± 4.4% (ITV) and 2.5 ± 4.8% (PTV) lower using AXB; whereas mean doses were 2.9 ± 4.9% (ITV) and 3.7 ± 5.1% (PTV) lower. Calculated AXB doses were significantly lower in one patient (difference in mean ITV and PTV doses, as well as in mean ITV and PTV D95 ranged from 22%-24%). However, the end respiratory phase GTV received at least 95% of the prescription dose. Review of 92 CBCT scans from all AAA patients revealed that the tumor was visualized in 82 images, and its position could be inferred in other images. The 2-year local progression-free survival was 100%. Conclusions: Patients with subcentimeter lung tumors are good candidates for SABR, given the dosimetry, ability to localize

  15. Results of radiofrequency ablation of liver tumors: experience of 134 cases

    Directory of Open Access Journals (Sweden)

    Marcelo Augusto Fontenelle Ribeiro Junior

    2008-12-01

    Full Text Available Objective: To study radiofrequency ablation of primary and metastatic livertumors. Methods: The authors present a series of 134 cases, 63 femalesand 71 males with a mean age of 61.2 years, in whom radiofrequencyablation was used either by laparotomy or percutaneously to treat 203lesions. The group was composed of 51 cases of hepatocellular carcinoma,four cases of cholangiocarcinoma, and cases of hepatic metastases, asfollows: 64 of colorectal cancer, 6 of neuroendocrine tumors, 5 of breastcancer, 1 case of pancreas cancer, 1 of kidney cancer, 1 of endometrialcancer and 1 of leiomyosarcoma. Results: Procedure-associatedmorbidity/mortality was 24.8 and 3.7%, respectively. Recurrence wasobserved in 12.7% within a mean time of 10.5 months. Conclusions:Radiofrequency ablation is a safe procedure and can be used in patientswith impaired hepatic function. For metastatic diseases, it does notreplace surgery but it can be associated with other procedures, such assurgery and transarterial chemoembolization, or after recurrence, leadingto greater probability of remaining disease-free.

  16. Light Weight Ceramic Ablators for Mars Follow-on Mission Vehicle Thermal Protection System

    Science.gov (United States)

    Tran, Huy K.; Rasky, Daniel J.; Hsu, Ming-Ta; Turan, Ryan

    1994-01-01

    New Light Weight Ceramic Ablators (LCA) were produced by using ceramic and carbon fibrous substrates, impregnated with silicone and phenolic resins. The special infiltration techniques (patent pending) were developed to control the amount of organic resins in the highly porous fiber matrices so that the final densities of LCA's range from 0.22 to 0.24 g/cc. This paper presents the thermal and ablative performance of the Silicone Impregnated Reusable Ceramic Ablators (SIRCA) in simulated entry conditions for Mars-Pathfinder in the Ames 60 MW Interaction Heating Facility (I HF). Arc jet test results yielded no evidence of char erosion and mass loss at high stagnation pressures to 0.25 atm. Minimal silica melt was detected on surface char at a stagnation pressure of 0.31 atm. Four ceramic substrates were used in the production of SIRCA's to obtain the effective of boron oxide present in substrate so the thermal performance of SIRCA's. A sample of SIRCA was also exposed to the same heating condition for five cycles and no significant mass loss or recession was observed. Tensile testing established that the SIRCA tensile strength is about a factor of two higher than that of the virgin substrates. Thermogravimetric Analysis (TGA) of the char in nitrogen and air showed no evidence of free carbon in the char. Scanning Electron Microscopy of the post test sample showed that the char surface consists of a fibrous structure that was sealed with a thin layer of silicon oxide melt.

  17. Near-IR imaging of thermal changes in enamel during laser ablation

    Science.gov (United States)

    Maung, Linn H.; Lee, Chulsung; Fried, Daniel

    2010-02-01

    The objective of this work was to observe the various thermal-induced optical changes that occur in the near-infrared (NIR) during drilling in dentin and enamel with the laser and the high-speed dental handpiece. Tooth sections of ~ 3 mm-thickness were prepared from extracted human incisors (N=60). Samples were ablated with a mechanically scanned CO2 laser operating at a wavelength of 9.3-μm, a 300-Hz laser pulse repetition rate, and a laser pulse duration of 10-20 μs. An InGaAs imaging camera was used to acquire real-time NIR images at 1300-nm of thermal and mechanical changes (cracks). Enamel was rapidly removed by the CO2 laser without peripheral thermal damage by mechanically scanning the laser beam while a water spray was used to cool the sample. Comparison of the peripheral thermal and mechanical changes produced while cutting with the laser and the high-speed hand-piece suggest that enamel and dentin can be removed at high speed by the CO2 laser without excessive peripheral thermal or mechanical damage. Only 2 of the 15 samples ablated with the laser showed the formation of small cracks while 9 out of 15 samples exhibited crack formation with the dental hand-piece. The first indication of thermal change is a decrease in transparency due to loss of the mobile water from pores in the enamel which increase lightscattering. To test the hypothesis that peripheral thermal changes were caused by loss of mobile water in the enamel, thermal changes were intentionally induced by heating the surface. The mean attenuation coefficient of enamel increased significantly from 2.12 +/- 0.82 to 5.08 +/- 0.98 with loss of mobile water due to heating.

  18. Phrenic nerve injury after radiofrequency ablation of lung tumors: retrospective evaluation of the incidence and risk factors.

    Science.gov (United States)

    Matsui, Yusuke; Hiraki, Takao; Gobara, Hideo; Uka, Mayu; Masaoka, Yoshihisa; Tada, Akihiro; Toyooka, Shinichi; Mitsuhashi, Toshiharu; Mimura, Hidefumi; Kanazawa, Susumu

    2012-06-01

    To retrospectively investigate the incidence of and risk factors for phrenic nerve injury after radiofrequency (RF) ablation of lung tumors. The study included 814 RF ablation procedures of lung tumors. To evaluate the development of phrenic nerve injury, chest radiographs obtained before and after the procedure were examined. Phrenic nerve injury was assumed to have developed if the diaphragmatic level was elevated after the procedure. To identify risk factors for phrenic nerve injury, multiple variables were compared between cases of phrenic nerve injury and randomly selected controls by using univariate analyses. Multivariate analysis was then performed to identify independent risk factors. Evaluation of phrenic nerve injury from chest radiographs was possible after 786 procedures. Evidence of phrenic nerve injury developed after 10 cases (1.3%). Univariate analysis revealed that larger tumor size (≥ 20 mm; P = .014), proximity of the phrenic nerve to the tumor (phrenic nerve injury. Multivariate analysis demonstrated that the proximity of the phrenic nerve to the tumor (phrenic nerve injury after RF ablation was 1.3%. The proximity of the phrenic nerve to the tumor was an independent risk factor for phrenic nerve injury. Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.

  19. Optoacoustic monitoring of cutting efficiency and thermal damage during laser ablation.

    Science.gov (United States)

    Bay, Erwin; Douplik, Alexandre; Razansky, Daniel

    2014-05-01

    Successful laser surgery is characterized by a precise cut and effective hemostasis with minimal collateral thermal damage to the adjacent tissues. Consequently, the surgeon needs to control several parameters, such as power, pulse repetition rate, and velocity of movements. In this study we propose utilizing optoacoustics for providing the necessary real-time feedback of cutting efficiency and collateral thermal damage. Laser ablation was performed on a bovine meat slab using a Q-switched Nd-YAG laser (532 nm, 4 kHz, 18 W). Due to the short pulse duration of 7.6 ns, the same laser has also been used for generation of optoacoustic signals. Both the shockwaves, generated due to tissue removal, as well as the normal optoacoustic responses from the surrounding tissue were detected using a single broadband piezoelectric transducer. It has been observed that the rapid reduction in the shockwave amplitude occurs as more material is being removed, indicating decrease in cutting efficiency, whereas gradual decrease in the optoacoustic signal likely corresponds to coagulation around the ablation crater. Further heating of the surrounding tissue leads to carbonization accompanied by a significant shift in the optoacoustic spectra. Our results hold promise for real-time monitoring of cutting efficiency and collateral thermal damage during laser surgery. In practice, this could eventually facilitate development of automatic cut-off mechanisms that will guarantee an optimal tradeoff between cutting and heating while avoiding severe thermal damage to the surrounding tissues.

  20. Linearly chirped fiber Bragg grating response to thermal gradient: from bench tests to the real-time assessment during in vivo laser ablations of biological tissue

    Science.gov (United States)

    Saccomandi, Paola; Varalda, Ambra; Gassino, Riccardo; Tosi, Daniele; Massaroni, Carlo; Caponero, Michele A.; Pop, Raoul; Korganbayev, Sanzhar; Perrone, Guido; Diana, Michele; Vallan, Alberto; Costamagna, Guido; Marescaux, Jacques; Schena, Emiliano

    2017-09-01

    The response of a fiber optic sensor [linearly chirped fiber Bragg grating (LCFBG)] to a linear thermal gradient applied on its sensing length (i.e., 1.5 cm) has been investigated. After these bench tests, we assessed their feasibility for temperature monitoring during thermal tumor treatment. In particular, we performed experiments during ex vivo laser ablation (LA) in pig liver and in vivo thermal ablation in animal models (pigs). We investigated the following: (i) the relationship between the full width at half maximum of the LCFBG spectrum and the temperature difference among the extremities of the LCFBG and (ii) the relationship between the mean spectrum wavelength and the mean temperature acting on the LCFBG sensing area. These relationships showed a linear trend during both bench tests and LA in animal models. Thermal sensitivity was significant although different values were found with regards to bench tests and animal experiments. The linear trend and significant sensitivity allow hypothesizing a future use of this kind of sensor to monitor both temperature gradient and mean temperature within a tissue undergoing thermal treatment.

  1. Perioperative outcomes of zero ischemia radiofrequency ablation-assisted tumor enucleation for renal cell carcinoma: results of 182 patients.

    Science.gov (United States)

    Zhang, Chengwei; Zhao, Xiaozhi; Guo, Suhan; Ji, Changwei; Wang, Wei; Guo, Hongqian

    2018-05-15

    To evaluate the perioperative outcomes of zero ischemia radiofrequency ablation-assisted tumor enucleation. Patients undergoing zero ischemia radiofrequency ablation-assisted tumor enucleation were retrospectively identified from July 2008 to March 2013. The tumor was enucleated after RFA treatment. R.E.N.A.L., PADUA and centrality index (C-index) score systems were used to assess each tumor case. We analyzed the correlation of perioperative outcomes with these scores. Postoperative complications were graded with Clavien-Dindo system. Multivariate logistic regression analyses were used to assess risk of complications. Among 182 patients assessed, median tumor size, estimated blood loss, hospital stay and operative time were 3.2 cm (IQR 2.8-3.4), 80 ml (IQR 50-120), 7 days (IQR 6-8) and 100 min (IQR 90-120), respectively. All three scoring systems were strongly correlated with estimated blood loss, hospital stay and operative time. We found 3 (1.6%) intraoperative and 23 (12.6%, 13 [7.1%] Grade 1 and 10 [5.5%] Grade 2 & 3a) postoperative complications. The median follow-up was 55.5 months (IQR 45-70). Additionally, the complexities of R.E.N.A.L., PADUA and C-index scores were significantly correlated with complication grades (P radiofrequency ablation-assisted tumor enucleation is considered an effective nephron-sparing treatment. Scoring systems could be useful for predicting perioperative outcomes of radiofrequency ablation-assisted tumor enucleation.

  2. Heme products post-radiofrequency ablation obscure tumor recurrence on MR but not on PET-CT

    Energy Technology Data Exchange (ETDEWEB)

    Ehsan, Syed Ramisa; Gooden, Casey E.; Schuster, David M. [Emory Univ. Hospital, Atlanta (United States)

    2012-06-15

    A 76-year-old male with non-small-cell lung cancer, post lobectomy, presented with hepatic metastatic disease and underwent radiofrequency ablation (RFA), a minimally invasive and safe approach for treatment of liver tumors. Gadolinium-enhanced MRI of the patient performed at our institution 5 months post-RFA leads to palliation, increased T1 signal at the RFA site believed to be post-RFA blood products. RFA leads to palliation, increased survival, and is better tolerated than other ablative techniques. It has also been associated with a low rate of local recurrence. Post-RFA, the target, lesion typically has hyperintense signal with T1-weighting, low signal on T2-weighting, and is non-enhancing following post-gadolinium administration. Recurrent disease typically demonstrates new enhancement, increased size, and development of T1-weighted hypointense and T2-weighted hyperintense regions. Subsequent positron emission tomography (PET/CT) of the patient demonstrated focal FDG uptake on the corresponding sagittal image, at the border of the prior RFA ablation zone, with maximal SUV of 6.9, Characteristic for recurrent hepatic metastasis. The photopenic area was at the epicenter of the RFA site. PET/CT imaging is also used to monitor residual tumor or recurrence after RFA. Lesions that show increased 18-fluorodeoxyglucose (FDG) uptake on PET become photopenic immediately after RFA, suggestive of complete ablation. Focal areas of increased FDG uptake within the ablated zone are suspicious for residual or recurrent disease. Reactive tissue is typically present in the periphery of the ablated lesion and has uniform low-grade FDG uptake, unlike the focal nodular intense uptake observed with active tumor.

  3. Lightweight Ablative and Ceramic Thermal Protection System Materials for NASA Exploration Systems Vehicles

    Science.gov (United States)

    Valentine, Peter G.; Lawrence, Timothy W.; Gubert, Michael K.; Milos, Frank S.; Kiser, James D.; Ohlhorst, Craig W.; Koenig, John R.

    2006-01-01

    As a collaborative effort among NASA Centers, the "Lightweight Nonmetallic Thermal Protection Materials Technology" Project was set up to assist mission/vehicle design trade studies, to support risk reduction in thermal protection system (TPS) material selections, to facilitate vehicle mass optimization, and to aid development of human-rated TPS qualification and certification plans. Missions performing aerocapture, aerobraking, or direct aeroentry rely on advanced heatshields that allow reductions in spacecraft mass by minimizing propellant requirements. Information will be presented on candidate materials for such reentry approaches and on screening tests conducted (material property and space environmental effects tests) to evaluate viable candidates. Seventeen materials, in three classes (ablatives, tiles, and ceramic matrix composites), were studied. In additional to physical, mechanical, and thermal property tests, high heat flux laser tests and simulated-reentry oxidation tests were performed. Space environmental effects testing, which included exposures to electrons, atomic oxygen, and hypervelocity impacts, was also conducted.

  4. Ablation of EIF5A2 induces tumor vasculature remodeling and improves tumor response to chemotherapy via regulation of matrix metalloproteinase 2 expression.

    Science.gov (United States)

    Wang, Feng-Wei; Cai, Mu-Yan; Mai, Shi-Juan; Chen, Jie-Wei; Bai, Hai-Yan; Li, Yan; Liao, Yi-Ji; Li, Chang-Peng; Tian, Xiao-Peng; Kung, Hsiang-Fu; Guan, Xin-Yuan; Xie, Dan

    2014-08-30

    Hepatocellular carcinoma (HCC) is a highly vascularized tumor with poor clinical outcome. Our previous work has shown that eukaryotic initiation factor 5A2 (EIF5A2) over-expression enhances HCC cell metastasis. In this study, EIF5A2 was identified to be an independent risk factor for poor disease-specific survival among HCC patients. Both in vitro and in vivo assays indicated that ablation of endogenous EIF5A2 inhibited tumor angiogenesis by reducing matrix metalloproteinase 2 (MMP-2) expression. Given that MMP-2 degrades collagen IV, a main component of the vascular basement membrane (BM), we subsequently investigated the effect of EIF5A2 on tumor vasculature remodeling using complementary approaches, including fluorescent immunostaining, transmission electron microscopy, tumor perfusion assays and tumor hypoxia assays. Taken together, our results indicate that EIF5A2 silencing increases tumor vessel wall continuity, increases blood perfusion and improves tumor oxygenation. Additionally, we found that ablation of EIF5A2 enhanced the chemosensitivity of HCC cells to 5-Fluorouracil (5-FU). Finally, we demonstrated that EIF5A2 might exert these functions by enhancing MMP-2 activity via activation of p38 MAPK and JNK/c-Jun pathways. This study highlights an important role of EIF5A2 in HCC tumor vessel remodeling and indicates that EIF5A2 represents a potential therapeutic target in the treatment of HCC.

  5. Vascular thermal adaptation in tumors and normal tissue in rats

    International Nuclear Information System (INIS)

    Nah, Byung Sik; Choi, Ihl-Bohng; Oh, Won Young; Osborn, James L.; Song, Chang W.

    1996-01-01

    Purpose: The vascular thermal adaptation in the R3230 adenocarcinoma, skin and muscle in the legs of Fischer rats was studied. Methods and Materials: The legs of Fischer rats bearing the R3230 AC adenocarcinoma (subcutaneously) were heated once or twice with a water bath, and the blood flow in the tumor, skin and muscle of the legs was measured with the radioactive microsphere method. Results: The blood flow in control R3230 AC tumors was 23.9 ml/100 g/min. The tumor blood flow increased about 1.5 times in 30 min and then markedly decreased upon heating at 44.5 deg. C for 90 min. In the tumors preheated 16 h earlier at 42.5 deg. C for 60 min, reheating at 44.5 deg. C increased the tumor blood flow by 2.5-fold in 30 min. Contrary to the decline in blood flow following an initial increase during the 44.5 deg. C heating without preheating, the tumor blood flow remained elevated throughout the 90 min reheating at 44.5 deg. C. These results indicated that thermal adaptation or thermotolerance developed in the tumor vasculatures after the preheating at 42.5 deg. C for 60 min. The magnitude of vascular thermal adaptation in the tumors 24 h and 48 h after the preheating, as judged from the changes in blood flow, were smaller than that 16 h after the preheating. Heating at 42.5 deg. C for 60 min induced vascular thermal adaptation also in the skin and muscle, which peaked in 48 h and 24 h, respectively, after the heating. Conclusion: Heating at 42.5 deg. C for 1 h induced vascular thermal adaptation in the R3230 AC tumor, skin, and muscle of rats that peaked 16-48 h after the heating. When the tumor blood vessels were thermally adapted, the tumor blood flow increased upon heating at temperatures that would otherwise reduce the tumor blood flow. Such an increase in tumor blood flow may hinder raising the tumor temperature while it may increase tumor oxygenation.

  6. Stereotactic ablative radiotherapy for small lung tumors with a moderate dose. Favorable results and low toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Duncker-Rohr, V.; Nestle, U. [Universitaetsklinikum Freiburg (Germany); Momm, F. [Ortenau Klinikum Offenburg (Germany)] [and others

    2013-01-15

    Background: Stereotactic ablative body radiotherapy (SBRT, SABR) is being increasingly applied because of its high local efficacy, e.g., for small lung tumors. However, the optimum dosage is still under discussion. Here, we report data on 45 lung lesions [non-small cell lung cancer (NSCLC) or metastases] in 39 patients treated between 2009 and 2010 by SABR. Patients and methods: SABR was performed with total doses of 35 Gy (5 fractions) or 37.5 Gy (3 fractions) prescribed to the 60% isodose line encompassing the planning target volume. Three-monthly follow-up CT scans were supplemented by FDG-PET/CT if clinically indicated. Results: The median follow-up was 17 months. Local progression-free survival rates were 90.5% (all patients), 95.0% (NSCLC), and 81.8% (metastases) at 1 year. At 2 years, the respective local progression-free survival rates were 80.5%, 95.0%, and 59.7%. Overall survival rates were 71.1% (all patients), 65.4% (NSCLC), and 83.3% (metastases) at 1 year. Overall survival rates at 2 years were 52.7%, 45.9%, and 66.7%, respectively. Acute side effects were mild. Conclusion: With the moderate dose schedule used, well-tolerated SABR led to favorable local tumor control as in other published series. Standardization in reporting the dose prescription for SABR is needed to allow comparison of different series in order to determine optimum dosage. (orig.)

  7. Lung Volume Reduction After Stereotactic Ablative Radiation Therapy of Lung Tumors: Potential Application to Emphysema

    Energy Technology Data Exchange (ETDEWEB)

    Binkley, Michael S. [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Shrager, Joseph B. [Division of Thoracic Surgery, Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States); Leung, Ann N. [Department of Radiology, Stanford University School of Medicine, Stanford, California (United States); Popat, Rita [Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California (United States); Trakul, Nicholas [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Department of Radiation Oncology, University of Southern California Keck School of Medicine, Los Angeles, California (United States); Atwood, Todd F.; Chaudhuri, Aadel [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Maxim, Peter G. [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States); Diehn, Maximilian, E-mail: Diehn@Stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States); Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California (United States); Loo, Billy W., E-mail: BWLoo@Stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States)

    2014-09-01

    Purpose: Lung volume reduction surgery (LVRS) improves dyspnea and other outcomes in selected patients with severe emphysema, but many have excessive surgical risk for LVRS. We analyzed the dose-volume relationship for lobar volume reduction after stereotactic ablative radiation therapy (SABR) of lung tumors, hypothesizing that SABR could achieve therapeutic volume reduction if applied in emphysema. Methods and Materials: We retrospectively identified patients treated from 2007 to 2011 who had SABR for 1 lung tumor, pre-SABR pulmonary function testing, and ≥6 months computed tomographic (CT) imaging follow-up. We contoured the treated lobe and untreated adjacent lobe(s) on CT before and after SABR and calculated their volume changes relative to the contoured total (bilateral) lung volume (TLV). We correlated lobar volume reduction with the volume receiving high biologically effective doses (BED, α/β = 3). Results: 27 patients met the inclusion criteria, with a median CT follow-up time of 14 months. There was no grade ≥3 toxicity. The median volume reduction of the treated lobe was 4.4% of TLV (range, −0.4%-10.8%); the median expansion of the untreated adjacent lobe was 2.6% of TLV (range, −3.9%-11.6%). The volume reduction of the treated lobe was positively correlated with the volume receiving BED ≥60 Gy (r{sup 2}=0.45, P=.0001). This persisted in subgroups determined by high versus low pre-SABR forced expiratory volume in 1 second, treated lobe CT emphysema score, number of fractions, follow-up CT time, central versus peripheral location, and upper versus lower lobe location, with no significant differences in effect size between subgroups. Volume expansion of the untreated adjacent lobe(s) was positively correlated with volume reduction of the treated lobe (r{sup 2}=0.47, P<.0001). Conclusions: We identified a dose-volume response for treated lobe volume reduction and adjacent lobe compensatory expansion after lung tumor SABR, consistent across

  8. Thermal effect of laser ablation on the surface of carbon fiber reinforced plastic during laser processing

    Science.gov (United States)

    Ohkubo, Tomomasa; Sato, Yuji; Matsunaga, Ei-ichi; Tsukamoto, Masahiro

    2018-02-01

    Although laser processing is widely used for many applications, the cutting quality of carbon fiber reinforced plastic (CFRP) decreases around the heat-affected zone (HAZ) during laser processing. Carbon fibers are exposed around the HAZ, and tensile strength decreases with increasing length of the HAZ. Some theoretical studies of thermal conductions that do not consider fluid dynamics have been performed; however, theoretical considerations that include the dynamics of laser ablation are scarce. Using removed mass and depth observed from experiments, the dynamics of laser ablation of CFRP with high-temperature and high-pressure of compressive gas is simulated herein. In this calculation, the mushroom-like shape of laser ablation is qualitatively simulated compared with experiments using a high-speed camera. Considering the removal temperature of the resin and the temperature distribution at each point on the surface, the simulation results suggest that a wide area of the resin is removed when the processing depth is shallow, and a rounded kerf is generated as the processing depth increases.

  9. Thermal protection for hypervelocity flight in earth's atmosphere by use of radiation backscattering ablating materials

    Science.gov (United States)

    Howe, John T.; Yang, Lily

    1991-01-01

    A heat-shield-material response code predicting the transient performance of a material subject to the combined convective and radiative heating associated with the hypervelocity flight is developed. The code is dynamically interactive to the heating from a transient flow field, including the effects of material ablation on flow field behavior. It accomodates finite time variable material thickness, internal material phase change, wavelength-dependent radiative properties, and temperature-dependent thermal, physical, and radiative properties. The equations of radiative transfer are solved with the material and are coupled to the transfer energy equation containing the radiative flux divergence in addition to the usual energy terms.

  10. Lightning Strike Ablation Damage Influence Factors Analysis of Carbon Fiber/Epoxy Composite Based on Coupled Electrical-Thermal Simulation

    Science.gov (United States)

    Yin, J. J.; Chang, F.; Li, S. L.; Yao, X. L.; Sun, J. R.; Xiao, Y.

    2017-10-01

    According to the mathematical analysis model constructed on the basis of energy-balance relationship in lightning strike, and accompany with the simplified calculation strategy of composite resin pyrolysis degree dependent electrical conductivity, an effective three dimensional thermal-electrical coupling analysis finite element model of composite laminate suffered from lightning current was established based on ABAQUS, to elucidate the effects of lighting current waveform parameters and thermal/electrical properties of composite laminate on the extent of ablation damage. Simulated predictions agree well with the composite lightning strike directed effect experimental data, illustrating the potential accuracy of the constructed model. The analytical results revealed that extent of composite lightning strike ablation damage can be characterized by action integral validly, there exist remarkable power function relationships between action integral and visual damage area, projected damage area, maximum damage depth and damage volume of ablation damage, and enhancing the electrical conductivity and specific heat of composite, ablation damage will be descended obviously, power function relationships also exist between electrical conductivity, specific heat and ablation damage, however, the impact of thermal conductivity on the extent of ablation damage is not notable. The conclusions obtained provide some guidance for composite anti-lightning strike structure-function integration design.

  11. Endoscopic ultrasound guided radiofrequency ablation, for pancreatic cystic neoplasms and neuroendocrine tumors

    Science.gov (United States)

    Pai, Madhava; Habib, Nagy; Senturk, Hakan; Lakhtakia, Sundeep; Reddy, Nageshwar; Cicinnati, Vito R; Kaba, Iyad; Beckebaum, Susanne; Drymousis, Panagiotis; Kahaleh, Michel; Brugge, William

    2015-01-01

    AIM: To outline the feasibility, safety, adverse events and early results of endoscopic ultrasound (EUS)-radiofrequency ablation (RFA) in pancreatic neoplasms using a novel probe. METHODS: This is a multi-center, pilot safety feasibility study. The intervention described was radiofrequency ablation (RF) which was applied with an innovative monopolar RF probe (1.2 mm Habib EUS-RFA catheter) placed through a 19 or 22 gauge fine needle aspiration (FNA) needle once FNA was performed in patients with a tumor in the head of the pancreas. The Habib™ EUS-RFA is a 1 Fr wire (0.33 mm, 0.013”) with a working length of 190 cm, which can be inserted through the biopsy channel of an echoendoscope. RF power is applied to the electrode at the end of the wire to coagulate tissue in the liver and pancreas. RESULTS: Eight patients [median age of 65 (range 27-82) years; 7 female and 1 male] were recruited in a prospective multicenter trial. Six had a pancreatic cystic neoplasm (four a mucinous cyst, one had intraductal papillary mucinous neoplasm and one a microcystic adenoma) and two had a neuroendocrine tumors (NET) in the head of pancreas. The mean size of the cystic neoplasm and NET were 36.5 mm (SD ± 17.9 mm) and 27.5 mm (SD ± 17.7 mm) respectively. The EUS-RFA was successfully completed in all cases. Among the 6 patients with a cystic neoplasm, post procedure imaging in 3-6 mo showed complete resolution of the cysts in 2 cases, whilst in three more there was a 48.4% reduction [mean pre RF 38.8 mm (SD ± 21.7 mm) vs mean post RF 20 mm (SD ± 17.1 mm)] in size. In regards to the NET patients, there was a change in vascularity and central necrosis after EUS-RFA. No major complications were observed within 48 h of the procedure. Two patients had mild abdominal pain that resolved within 3 d. CONCLUSION: EUS-RFA of pancreatic neoplasms with a novel monopolar RF probe was well tolerated in all cases. Our preliminary data suggest that the procedure is straightforward and safe. The

  12. Measurement of thermally ablated lesions in sonoelastographic images using level set methods

    Science.gov (United States)

    Castaneda, Benjamin; Tamez-Pena, Jose Gerardo; Zhang, Man; Hoyt, Kenneth; Bylund, Kevin; Christensen, Jared; Saad, Wael; Strang, John; Rubens, Deborah J.; Parker, Kevin J.

    2008-03-01

    The capability of sonoelastography to detect lesions based on elasticity contrast can be applied to monitor the creation of thermally ablated lesion. Currently, segmentation of lesions depicted in sonoelastographic images is performed manually which can be a time consuming process and prone to significant intra- and inter-observer variability. This work presents a semi-automated segmentation algorithm for sonoelastographic data. The user starts by planting a seed in the perceived center of the lesion. Fast marching methods use this information to create an initial estimate of the lesion. Subsequently, level set methods refine its final shape by attaching the segmented contour to edges in the image while maintaining smoothness. The algorithm is applied to in vivo sonoelastographic images from twenty five thermal ablated lesions created in porcine livers. The estimated area is compared to results from manual segmentation and gross pathology images. Results show that the algorithm outperforms manual segmentation in accuracy, inter- and intra-observer variability. The processing time per image is significantly reduced.

  13. Terminology and reporting criteria for radiofrequency ablation of tumors in the scientific literature: Systematic review of compliance with reporting standards

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Tae Wook; Rhim, Hyun Chul; Lee, Min Woo; Kim, Young Sun; Choi, Dongil; Lim, Hyo Keun [Dept. of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2014-02-15

    To perform a systematic review of compliance with standardized terminology and reporting criteria for radiofrequency (RF) tumor ablation, proposed by the International Working Group on Image-Guided Tumor Ablation in 2003, in the published reports. Literature search in the PubMed database was performed using index keywords, PubMed limit system, and eligibility criteria. The entire content of each article was reviewed to assess the terminology used for procedure terms, imaging findings, therapeutic efficacy, follow-up, and complications. Accuracy of the terminology and the use of alternative terms instead of standard terminology were analyzed. In addition, disparities in accuracy of terminology in articles according to the medical specialty and the type of radiology journal were evaluated. Among the articles (n = 308) included in this study, the accuracy of the terms 'procedure or session', 'treatment', 'index tumor', 'ablation zone', 'technical success', 'primary technique effectiveness rate', 'secondary technique effectiveness rate', 'local tumor progression', 'major complication', and 'minor complication' was 97% (298/307), 97% (291/300), 8% (25/307), 65% (103/159), 55% (52/94), 33% (42/129), 94% (17/18), 45% (88/195), 99% (79/80), and 100% (77/77), respectively. The overall accuracy of each term showed a tendency to improve over the years. The most commonly used alternative terms for 'technical success' and 'local tumor progression' were 'complete ablation' and 'local (tumor) recurrence', respectively. The accuracy of terminology in articles published in radiology journals was significantly greater than that of terminology in articles published in non-radiology journals, especially in Radiology and The Journal of Vascular and Interventional Radiology. The proposal for standardization of terminology and reporting criteria for

  14. The ablated volume and the thermal field distribution in swine vertebral body created by multi-polar radiofrequency ablation: an experiment in vitro

    International Nuclear Information System (INIS)

    Peng Zhaohong; Zhao Wei; Shen Jin; Hu Jihong; Li Zhaopeng; Wang Tao

    2009-01-01

    Objective: To observe the extent of bone coagulation and the thermal field distribution created in ablating the swine vertebral bodies in vitro with multi-polar radiofrequency and to discuss the correlation between the electrode position in the vertebral body and the safety of the spinal cord as well as the soft tissue injury around the vertebral body. Methods: Thirty fresh adult porcine vertebrae were randomly and equally divided into two groups. The depth of the electrode needle was 10 mm or 20 mm.When the ablation process reached to a stable state, the temperature at the scheduled spots was estimated. Twenty minutes after ablation, the vertebral body was cut along the electrode needle plane and also along the plane perpendicular to the electrode needle to observe the extent of bone coagulation. Results: The temperature at the scheduled spots reached to a stable state in 3.5 minutes. The more close to the electrode the spot was, the more quickly the temperature rose. No soft tissue injury around the vertebral body was observed in both groups and no spinal cord injury occurred when the electrode needle was 10 mm or 20 mm deep in the vertebral body. Conclusion: In treating vertebral metastases, the radiofrequency ablation is safe and reliable if the posterior wall of the vertebral body remains intact. (authors)

  15. Laser ablation in CdZnTe crystal due to thermal self-focusing: Secondary phase hydrodynamic expansion

    Energy Technology Data Exchange (ETDEWEB)

    Medvid’, A., E-mail: mychko@latnet.lv [Riga Technical University, 3 Paula Valdena Str., LV-1048 Riga (Latvia); Mychko, A.; Dauksta, E. [Riga Technical University, 3 Paula Valdena Str., LV-1048 Riga (Latvia); Kosyak, V. [Sumy State University, 2, Rymskogo-Korsakova St., 40007 Sumy (Ukraine); Grase, L. [Riga Technical University, 3 Paula Valdena Str., LV-1048 Riga (Latvia)

    2016-06-30

    Highlights: • We found two laser induced threshold intensity for CdZnTe crystal. • The laser beam self-focusing lead to increase of intensity of laser radiation at exit surface. • Laser ablation is a result of Te inclusion hydrodynamic expansion. - Abstract: The present paper deals with the laser ablation in CdZnTe crystal irradiated by pulsed infrared laser. Two values of threshold intensities of the laser ablation were determined, namely of about 8.5 and 6.2 MW/cm{sup 2} for the incident and the rear surfaces, correspondingly. Lower intensity of the laser ablation for the rear surface is explained by thermal self-focusing of the laser beam in the CdZnTe crystal due to heating of Te inclusions with a following hydrodynamic expansion.

  16. Clinical Implementation of Intrafraction Cone Beam Computed Tomography Imaging During Lung Tumor Stereotactic Ablative Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ruijiang; Han, Bin; Meng, Bowen [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Maxim, Peter G.; Xing, Lei; Koong, Albert C. [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States); Diehn, Maximilian, E-mail: Diehn@Stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States); Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California (United States); Loo, Billy W., E-mail: BWLoo@Stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States)

    2013-12-01

    Purpose: To develop and clinically evaluate a volumetric imaging technique for assessing intrafraction geometric and dosimetric accuracy of stereotactic ablative radiation therapy (SABR). Methods and Materials: Twenty patients received SABR for lung tumors using volumetric modulated arc therapy (VMAT). At the beginning of each fraction, pretreatment cone beam computed tomography (CBCT) was used to align the soft-tissue tumor position with that in the planning CT. Concurrent with dose delivery, we acquired fluoroscopic radiograph projections during VMAT using the Varian on-board imaging system. Those kilovolt projections acquired during millivolt beam-on were automatically extracted, and intrafraction CBCT images were reconstructed using the filtered backprojection technique. We determined the time-averaged target shift during VMAT by calculating the center of mass of the tumor target in the intrafraction CBCT relative to the planning CT. To estimate the dosimetric impact of the target shift during treatment, we recalculated the dose to the GTV after shifting the entire patient anatomy according to the time-averaged target shift determined earlier. Results: The mean target shift from intrafraction CBCT to planning CT was 1.6, 1.0, and 1.5 mm; the 95th percentile shift was 5.2, 3.1, 3.6 mm; and the maximum shift was 5.7, 3.6, and 4.9 mm along the anterior-posterior, left-right, and superior-inferior directions. Thus, the time-averaged intrafraction gross tumor volume (GTV) position was always within the planning target volume. We observed some degree of target blurring in the intrafraction CBCT, indicating imperfect breath-hold reproducibility or residual motion of the GTV during treatment. By our estimated dose recalculation, the GTV was consistently covered by the prescription dose (PD), that is, V100% above 0.97 for all patients, and minimum dose to GTV >100% PD for 18 patients and >95% PD for all patients. Conclusions: Intrafraction CBCT during VMAT can provide

  17. Salient points in reconstruction of nasal skin after tumor ablation with local flaps

    Directory of Open Access Journals (Sweden)

    Ali Ebrahimi

    2016-01-01

    Full Text Available Objective: A variety of nasal skin reconstruction methods are available to meet the esthetic patient's needs. In this article, we review some of modifications of these procedures and share our experience in reconstruction of different parts of the nasal skin following skin tumor ablation. Patients and Methods : From January 2010 to January 2014, 171 patients underwent nasal skin reconstruction after excising cancerous lesions of the involved nasal skin. The patient's history, pre- and post-operation photographs, and the surgery data were collected and assessed. Demographic data related to the type of cancer, defect size and location, type of reconstruction were collected. Results: A variety of local flaps were used based on location and defect features. Nearly all flaps healed primarily without postsurgical significant complications. Conclusion: According to the results and the outcomes of the operations, we concluded that a certain flaps are more effective than others in nasal skin reconstruction. Local flap reconstruction of the nose has good esthetic result with low complication rate.

  18. RFA Guardian: Comprehensive Simulation of Radiofrequency Ablation Treatment of Liver Tumors.

    Science.gov (United States)

    Voglreiter, Philip; Mariappan, Panchatcharam; Pollari, Mika; Flanagan, Ronan; Blanco Sequeiros, Roberto; Portugaller, Rupert Horst; Fütterer, Jurgen; Schmalstieg, Dieter; Kolesnik, Marina; Moche, Michael

    2018-01-15

    The RFA Guardian is a comprehensive application for high-performance patient-specific simulation of radiofrequency ablation of liver tumors. We address a wide range of usage scenarios. These include pre-interventional planning, sampling of the parameter space for uncertainty estimation, treatment evaluation and, in the worst case, failure analysis. The RFA Guardian is the first of its kind that exhibits sufficient performance for simulating treatment outcomes during the intervention. We achieve this by combining a large number of high-performance image processing, biomechanical simulation and visualization techniques into a generalized technical workflow. Further, we wrap the feature set into a single, integrated application, which exploits all available resources of standard consumer hardware, including massively parallel computing on graphics processing units. This allows us to predict or reproduce treatment outcomes on a single personal computer with high computational performance and high accuracy. The resulting low demand for infrastructure enables easy and cost-efficient integration into the clinical routine. We present a number of evaluation cases from the clinical practice where users performed the whole technical workflow from patient-specific modeling to final validation and highlight the opportunities arising from our fast, accurate prediction techniques.

  19. Detection of thermal gradients through fiber-optic Chirped Fiber Bragg Grating (CFBG): Medical thermal ablation scenario

    Science.gov (United States)

    Korganbayev, Sanzhar; Orazayev, Yerzhan; Sovetov, Sultan; Bazyl, Ali; Schena, Emiliano; Massaroni, Carlo; Gassino, Riccardo; Vallan, Alberto; Perrone, Guido; Saccomandi, Paola; Arturo Caponero, Michele; Palumbo, Giovanna; Campopiano, Stefania; Iadicicco, Agostino; Tosi, Daniele

    2018-03-01

    In this paper, we describe a novel method for spatially distributed temperature measurement with Chirped Fiber Bragg Grating (CFBG) fiber-optic sensors. The proposed method determines the thermal profile in the CFBG region from demodulation of the CFBG optical spectrum. The method is based on an iterative optimization that aims at minimizing the mismatch between the measured CFBG spectrum and a CFBG model based on coupled-mode theory (CMT), perturbed by a temperature gradient. In the demodulation part, we simulate different temperature distribution patterns with Monte-Carlo approach on simulated CFBG spectra. Afterwards, we obtain cost function that minimizes difference between measured and simulated spectra, and results in final temperature profile. Experiments and simulations have been carried out first with a linear gradient, demonstrating a correct operation (error 2.9 °C); then, a setup has been arranged to measure the temperature pattern on a 5-cm long section exposed to medical laser thermal ablation. Overall, the proposed method can operate as a real-time detection technique for thermal gradients over 1.5-5 cm regions, and turns as a key asset for the estimation of thermal gradients at the micro-scale in biomedical applications.

  20. Magnetic Thermal Ablation Using Ferrofluids: Influence of Administration Mode on Biological Effect in Different Porcine Tissues

    International Nuclear Information System (INIS)

    Bruners, Philipp; Hodenius, Michael; Baumann, Martin; Oversohl, Jessica; Guenther, Rolf W.; Schmitz-Rode, Thomas; Mahnken, Andreas H.

    2008-01-01

    The purpose of this study was to compare the effects of magnetic thermal ablation in different porcine tissues using either a singular injection or a continuous infusion of superparamagnetic iron oxide nanoparticles. In the first setting samples of three ferrofluids containing different amounts of iron (1:171, 2:192, and 3:214 mg/ml) were singularly interstitially injected into specimens of porcine liver, kidney, and muscle (n = 5). Then the specimens were exposed to an alternating magnetic field (2.86 kA/m, 190 kHz) generated by a circular coil for 5 min. In the second experimental setup ferrofluid samples were continuously interstitially infused into the tissue specimens during the exposure to the magnetic field. To measure the temperature increase two fiber-optic temperature probes with a fixed distance of 0.5 cm were inserted into the specimens along the puncture tract of the injection needle and the temperature was measured every 15 s. Finally, the specimens were dissected, the diameters of the created thermal lesions were measured, and the volumes were calculated and compared. Compared to continuous infusion, a single injection of ferrofluids resulted in smaller coagulation volumes in all tissues. Significant differences regarding coagulation volume were found in kidney and muscle specimens. The continuous infusion technique led to more elliptically shaped coagulation volumes due to larger diameters along the puncture tract. Our data show the feasibility of magnetic thermal ablation using either a single interstitial injection or continuous infusion for therapy of lesions in muscle, kidney, and liver. Continuous infusion of ferrofluids results in larger zones of necrosis compared to a single injection technique.

  1. Percutaneous radiofrequency ablation for a recurrent metastasis after resection of liver metastases from an ileal clear-cell sarcoma: Long-term local tumor control.

    Science.gov (United States)

    Seo, Jung Wook

    2017-12-01

    Clear-cell sarcomas (CCSs) in the gastrointestinal tract are extremely rare and aggressive tumors. We present the first case of a CCS arising in the ileum and metastasizing to the liver; our patient was a 60-year-old man. After the resection of the CCS and the liver metastases, a new liver metastasis developed, which was treated via percutaneous radiofrequency ablation only. At the 5-year follow-up, the ablated region was stable without local tumor progression. Percutaneous radiofrequency ablation is a viable local treatment option for recurrent metastases from an ileal CCS if they are detected when small and at an early stage in follow-up studies.

  2. Ultrasound-guided laser thermal ablation in the treatment of autonomous hyperfunctioning thyroid nodules and compressive nontoxic nodular goiter.

    Science.gov (United States)

    Spiezia, Stefano; Vitale, Giovanni; Di Somma, Carolina; Pio Assanti, Angelo; Ciccarelli, Antonio; Lombardi, Gaetano; Colao, Annamaria

    2003-10-01

    Percutaneous laser thermal ablation (LTA) has been applied in several tumors. In this study we evaluated the safety and long-term efficacy of LTA in the treatment of benign thyroid nodules. Seven patients with autonomous hyperfunctioning thyroid nodule (group A) and five patients with compressive nodular goiter (group B) were treated with LTA. Up to three needles were positioned centrally in the thyroid nodule and laser fiber was placed in the lumen of the needle. Laser illumination was performed reaching a maximal energy deposition of 1800 J per fiber. Thyroid nodule volume, endocrinologic, and clinical evaluation were performed at baseline, 3, and 12 months after the treatment. Scintigraphy was performed at diagnosis and 12 months after the first session in group A. In group A, mean thyroid volume decreased from 3.15 +/- 1.26 mL to 0.83 +/- 0.49 mL (p thyroid volume decreased from 11.14 +/- 4.99 mL to 3.73 +/- 1.47 mL (p thyroid nodules.

  3. Use of Radiofrequency Ablation in Benign Thyroid Nodules: A Literature Review and Updates

    OpenAIRE

    Wong, KP; Lang, HHB

    2013-01-01

    Successful thermal ablation using radiofrequency has been reported in various tumors including liver or kidney tumors. Nonsurgical minimally invasive ablative therapy such as radiofrequency ablation (RFA) has been reported to be a safe and efficient treatment option in managing symptomatic cold thyroid nodules or hyperfunctioning thyroid nodules. Pressure and cosmetic symptoms have been shown to be significantly improved both in the short and long terms after RFA. For hyperfunctioning thyroid...

  4. [Application of TB type thermal balloon endometrial ablation for the treatment of abnormal uterine bleeding].

    Science.gov (United States)

    Wang, W; Zhai, Y; Zhang, Z H; Li, Y; Zhang, Z Y

    2016-11-08

    Objective: To investigate the clinical efficacy, safety and promotion value of TB type thermal balloon endometrial ablation in the treatment of abnormal uterine bleeding. Methods: Fourty three patients who had received TB type endometrial ablation system for treatment of abnormal uterine bleeding from January, 2015 to January, 2016 in theDepartment of gynecology, Beijing Chaoyang Hospital were enrolled in this study. The intra-operative and post-operative complications and improvement of abnormal uterine bleeding and dysmenorrhea were observed. Results: There were nointra-operative complication occurred, such as uterine perforation, massive hemorrhage or surrounding organ damage. At 6 months after operation, 32 patients developed amenorrhea, 6 developed menstrual spotting, 3 developed menstruation with a small volume and 1 had a normal menstruation. No menstruation with an increased volume occurred. The occurrence of amenorrhea was 76.19% and the response rate was 97.62%.At 6 months after operation, 1 case had no response, 2 cases had partial response and 11 cases had complete response among the 14 cases of pre-operative dysmenorrhea; only 3 cases still had anemia among the 23 cases of pre-operative anemia. Compared with before treatment, patients with dysmenorrhea and anemia both significantly reduced with a statistically significant difference( P abnormal uterine bleeding, which could have clinical promotion practice.

  5. Activity-based cost analysis of hepatic tumor ablation using CT-guided high-dose rate brachytherapy or CT-guided radiofrequency ablation in hepatocellular carcinoma.

    Science.gov (United States)

    Schnapauff, D; Collettini, F; Steffen, I; Wieners, G; Hamm, B; Gebauer, B; Maurer, M H

    2016-02-25

    To analyse and compare the costs of hepatic tumor ablation with computed tomography (CT)-guided high-dose rate brachytherapy (CT-HDRBT) and CT-guided radiofrequency ablation (CT-RFA) as two alternative minimally invasive treatment options of hepatocellular carcinoma (HCC). An activity based process model was created determining working steps and required staff of CT-RFA and CT-HDRBT. Prorated costs of equipment use (purchase, depreciation, and maintenance), costs of staff, and expenditure for disposables were identified in a sample of 20 patients (10 treated by CT-RFA and 10 by CT-HDRBT) and compared. A sensitivity and break even analysis was performed to analyse the dependence of costs on the number of patients treated annually with both methods. Costs of CT-RFA were nearly stable with mean overall costs of approximately 1909 €, 1847 €, 1816 € and 1801 € per patient when treating 25, 50, 100 or 200 patients annually, as the main factor influencing the costs of this procedure was the single-use RFA probe. Mean costs of CT-HDRBT decreased significantly per patient ablation with a rising number of patients treated annually, with prorated costs of 3442 €, 1962 €, 1222 € and 852 € when treating 25, 50, 100 or 200 patients, due to low costs of single-use disposables compared to high annual fix-costs which proportionally decreased per patient with a higher number of patients treated annually. A break-even between both methods was reached when treating at least 55 patients annually. Although CT-HDRBT is a more complex procedure with more staff involved, it can be performed at lower costs per patient from the perspective of the medical provider when treating more than 55 patients compared to CT-RFA, mainly due to lower costs for disposables and a decreasing percentage of fixed costs with an increasing number of treatments.

  6. A framework for continuous target tracking during MR-guided high intensity focused ultrasound thermal ablations in the abdomen

    NARCIS (Netherlands)

    Zachiu, Cornel; Denis de Senneville, Baudouin; Dmitriev, Ivan D.; Moonen, Chrit T.W.; Ries, Mario

    2017-01-01

    Background: During lengthy magnetic resonance-guided high intensity focused ultrasound (MRg-HIFU) thermal ablations in abdominal organs, the therapeutic work-flow is frequently hampered by various types of physiological motion occurring at different time-scales. If left un-addressed this can lead to

  7. Thermal Ablation of the Pancreas With Intraoperative High-Intensity Focused Ultrasound: Safety and Efficacy in a Porcine Model.

    Science.gov (United States)

    Dupré, Aurélien; Melodelima, David; Pflieger, Hannah; Chen, Yao; Vincenot, Jérémy; Kocot, Anthony; Langonnet, Stéphan; Rivoire, Michel

    2017-02-01

    New focal destruction technologies such as high-intensity focused ultrasound (HIFU) may improve the prognosis of pancreatic ductal adenocarcinoma. Our objectives were to demonstrate the safety and efficacy of intraoperative pancreatic HIFU ablation in a porcine model. In a porcine model (N = 12), a single HIFU ablation was performed in either the body or tail of the pancreas, distant to superior mesenteric vessels. All animals were sacrificed on the eighth day. The primary objective was to obtain an HIFU ablation measuring at least 1 cm without premature death. In total, 12 HIFU ablations were carried out. These ablations were performed within 160 seconds and on average measured 20 (15-27) × 16 (8-26) mm. The primary objective was fulfilled in all but 1 pig. There were no premature deaths or severe complications. High-intensity focused ultrasound treatment was associated with a transitory increase in amylase and lipase levels, and pseudocysts were observed in half of the pigs without being clinically apparent. All ablations were well delimited at both gross and histological examinations. Intraoperative thermal destruction of porcine pancreas with HIFU is feasible. Reproducibility and safety have to be confirmed when applied close to mesenteric vessels and in long-term preclinical studies.

  8. Diagnostic Ability of Percutaneous Needle Biopsy Immediately After Radiofrequency Ablation for Malignant Lung Tumors: An Initial Experience

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Takaaki, E-mail: t-hasegawa@aichi-cc.jp [Aichi Cancer Center Hospital, Department of Diagnostic and Interventional Radiology (Japan); Kondo, Chiaki [Aichi Cancer Center Hospital, Department of Pathology and Molecular Diagnosis (Japan); Sato, Yozo; Inaba, Yoshitaka; Yamaura, Hidekazu; Kato, Mina; Murata, Shinichi; Onoda, Yui [Aichi Cancer Center Hospital, Department of Diagnostic and Interventional Radiology (Japan); Kuroda, Hiroaki; Sakao, Yukinori [Aichi Cancer Center Hospital, Department of Thoracic Surgery (Japan); Yatabe, Yasushi [Aichi Cancer Center Hospital, Department of Pathology and Molecular Diagnosis (Japan)

    2016-08-15

    PurposeTo evaluate the safety and diagnostic ability of percutaneous needle biopsy performed immediately after lung radiofrequency ablation (RFA).Materials and MethodsFrom May 2013 to April 2014, percutaneous needle biopsy was performed immediately after RFA for 3 patients (2 men and 1 woman, aged 57–76 years) who had lung tumors measuring 1.3–2.6 cm in diameter. All patients had prior history of malignancy, and all tumors were radiologically diagnosed as malignant. Obtained specimens were pathologically classified using standard hematoxylin and eosin staining.ResultsWe completed three planned sessions of RFA followed by percutaneous needle biopsy, all of which obtained tumor tissue that could be pathologically diagnosed. Two tumors were metastatic from renal clear cell carcinoma and rectal adenocarcinoma, respectively; one tumor was primary lung adenocarcinoma. There was no death or major complication related to the procedures. Although pneumothorax occurred in two patients, these resolved without the need for aspiration or chest tube placement. Tumor seeding was not observed, but 21 months after the procedure, one case developed local tumor progression that was treated by additional RFA.ConclusionPathologic diagnosis was possible by needle biopsy immediately after RFA for lung tumors. This technique may reduce the risks and efforts of performing biopsy and RFA on separate occasions.

  9. Conformal Ablative Thermal Protection Systems (CA-TPS) for Venus and Saturn Backshells

    Science.gov (United States)

    Beck, R.; Gasch, M.; Stackpoole, M.; Wilder, M.; Boghozian, T.; Chavez-Garcia, J.; Prabhu, D.; Kazemba, C.; Venkatapathy, E.

    2015-01-01

    The new conformal ablator C-PICA, which was developed under STMD GCD, is an optimal candidate for use on the backshells for high velocity entry vehicles at both Venus and Saturn. The material has been tested at heat fluxes up to 400 Wcm2 in shear and over 1800 Wcm2 and 1.5 atm in stagnation with good results. C-PICA has similar density to PICA, but shows half the thermal penetration and similar recession at the same conditions, allowing for a lighter weight TPS to be flown. This poster for VEXAG will show the progress made in the development of the material and why it should be considered for use.

  10. Studying the thermal performance of a bipolar radiofrequency ablation with an improved electrode matrix system: In vitro experiments and modelling

    International Nuclear Information System (INIS)

    Shao, Y.L.; Leo, H.L.; Chua, K.J.

    2017-01-01

    Highlights: • We made judicious modification to the Penne’s equation in the process of developing our model. We consider the liver to consist of tumor and health tissue. The model has been validated with experimental data. • The proposed electrode system can reduce the tissue volume damage outside the electrodes. The designed building unit with 10 mm inter-electrode distance is the optimal choice to achieve desired ablation zone. • The influence of blood vessel is relatively small for using this electrode system. A spatial distance of 13 mm is deemed as the safe distance between the wall of the central probe and the large vessel. • This proposed electrode system demonstrated higher ablation stability even for tissue regions that are close to blood vessels. The system is better suited for matrix-type RFA. - Abstract: Radiofrequency ablation (RFA) is becoming an effective treatment method for both primary tumors and tumors that have metastasized. Large tumors in difficult anatomic locations can be treated by RFA technologies. However, constant size and regular shape of damage zones cannot be obtained by recent RFA technologies. The aim of this study is to optimize the stability of RFA treatment by employing a newly proposed bipolar electrode system. A hepatic RFA mathematical model is developed by the finite element method approach. The model is validated with the experimental data. This model is then used to verify the reliability and stability of the proposed electrode system. Simulated results showed the cross section of the ablation zone utilizing designed electrode system approximates a square. In addition, the fraction of the necrosed tissue with this electrode pattern turned out to be larger than the fraction with single-probe RFA techniques. This system demonstrated higher ablation stability even for tissue regions that are close to blood vessels. The proposed electrode system is better suited for matrix-type RFA.

  11. Tumour eradication using synchronous thermal ablation and Hsp90 chemotherapy with protein engineered triblock biopolymer-geldanamycin conjugates.

    Science.gov (United States)

    Chen, Yizhe; Youn, Pilju; Pysher, Theodore J; Scaife, Courtney L; Furgeson, Darin Y

    2014-12-01

    Hepatocellular carcinoma (HCC) suffers high tumour recurrence rate after thermal ablation. Heat shock protein 90 (Hsp90) induced post-ablation is critical for tumour survival and progression. A combination therapy of thermal ablation and polymer conjugated Hsp90 chemotherapy was designed and evaluated for complete tumour eradication of HCC. A thermo-responsive, elastin-like polypeptide (ELP)-based tri-block biopolymer was developed and conjugated with a potent Hsp90 inhibitor, geldanamycin (GA). The anti-cancer efficacy of conjugates was evaluated in HCC cell cultures with and without hyperthermia (43 °C). The conjugates were also administered twice weekly in a murine HCC model as a single treatment or in combination with single electrocautery as the ablation method. ELP-GA conjugates displayed enhanced cytotoxicity in vitro and effective heat shock inhibition under hyperthermia. The conjugates alone significantly slowed the tumour growth without systemic toxicity. Four doses of thermo-responsive ELP-GA conjugates with concomitant simple electrocautery accomplished significant Hsp90 inhibition and sustained tumour suppression. Hsp90 inhibition plays a key role in preventing the recurrence of HCC, and the combination of ablation with targeted therapy holds great potential to improve prognosis and survival of HCC patients.

  12. Ablation of musculoskeletal metastases: pain palliation, fracture risk reduction, and oligometastatic disease.

    Science.gov (United States)

    Kurup, Anil Nicholas; Callstrom, Matthew R

    2013-12-01

    Thermal ablation is an effective, minimally invasive alternative to conventional therapies in the palliation of painful musculoskeletal metastases and an emerging approach to obtain local tumor control in the setting of limited metastatic disease. Various thermal ablation technologies have been applied to bone and soft tissue tumors and may be used in combination with percutaneous cement instillation for skeletal lesions with or at risk for pathologic fracture. This article reviews current practices of percutaneous ablation of musculoskeletal metastases with an emphasis on radiofrequency ablation and cryoablation of painful skeletal metastases. © 2013 Elsevier Inc. All rights reserved.

  13. Thermal and Ablative Properties of Ipns and Composites of High Ortho Resole Resin and Difurfurylidene Acetone

    Directory of Open Access Journals (Sweden)

    Tariq S. NAJIM

    2008-12-01

    Full Text Available High ortho resole resin was prepared by condensation of phenol with excess of formaldehyde in the presence of magnesium oxide as catalyst. Reaction of furfuraldehyde with acetone in basic medium led to difurfurylidene acetone (DFA. Their interpenetrating polymer network (IPNS were obtained by the reaction of predetermined quantities of difurfurylidene acetone and high ortho resole using p-toluene sulphonic acid (PTSA as curing agent. The thermal behavior of the resins was studied using thermogravimetry (TG under ambient and nitrogen atmospheres over a temperature range of (25-1000 Cº. It was observed that the IPN of 20% DFA – 80% resole has higher thermal stability than that of resole alone and the decomposition temperature was higher by 80 Cº. This behavior was attributed to highly cross linked structure and thermally stable backbone of ploy difurfurylidene acetone due to formation of ladder structure.Impregnation of chopped fiber glass type (E with the polymeric solutions was used to prepare their composites, and the ablative properties were investigated according to ASTM E-285 –80. It was observed that the IPN of (DFA- resol perform better than the resole composite alone.

  14. Radiofrequency ablation of liver metastases-software-assisted evaluation of the ablation zone in MDCT: tumor-free follow-up versus local recurrent disease.

    Science.gov (United States)

    Keil, Sebastian; Bruners, Philipp; Schiffl, Katharina; Sedlmair, Martin; Mühlenbruch, Georg; Günther, Rolf W; Das, Marco; Mahnken, Andreas H

    2010-04-01

    The purpose of this study was to investigate differences in change of size and CT value between local recurrences and tumor-free areas after CT-guided radiofrequency ablation (RFA) of hepatic metastases during follow-up by means of dedicated software for automatic evaluation of hepatic lesions. Thirty-two patients with 54 liver metastases from breast or colorectal cancer underwent triphasic contrast-enhanced multidetector-row computed tomography (MDCT) to evaluate hepatic metastatic spread and localization before CT-guided RFA and for follow-up after intervention. Sixteen of these patients (65.1 + or - 10.3 years) with 30 metastases stayed tumor-free (group 1), while the other group (n = 16 with 24 metastases; 62.0 + or - 13.8 years) suffered from local recurrent disease (group 2). Applying an automated software tool (SyngoCT Oncology; Siemens Healthcare, Forchheim, Germany), size parameters (volume, RECIST, WHO) and attenuation were measured within the lesions before, 1 day after, and 28 days after RFA treatment. The natural logarithm (ln) of the quotient of the volume 1 day versus 28 days after RFA treament was computed: lnQ1//28/0(volume). Analogously, ln ratios of RECIST, WHO, and attenuation were computed and statistically evaluated by repeated-measures ANOVA. One lesion in group 2 was excluded from further evaluation due to automated missegmentation. Statistically significant differences between the two groups were observed with respect to initial volume, RECIST, and WHO (p free and local-recurrent ablation zones with respect to the corresponding size parameters. A new parameter (lnQ1//28/0(volume/RECIST/WHO/attenuation)) was introduced, which appears to be of prognostic value at early follow-up CT.

  15. Biliary obstruction caused by intra-biliary tumor growth from recurred hepatocellular carcinoma after radiofrequency ablation: Case report

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Ji Hyun; Kim, Jae Won [Dept. of Radiology, Yeungnam University College of Medicine, Daegu (Korea, Republic of)

    2014-04-15

    A 59-year-old man with a known central hepatocellular carcinoma (HCC) underwent a trans-arterial-chemo-embolization (TACE) and a post-TACE percutaneous radiofrequency ablation (PRFA). Two months after the PRFA, the patient presented jaundice and an abdominal computed tomography was obtained. An arterial enhancing mass adjacent to the ablated necrotic lesion with a continuously coexisting mass inside the right hepatic duct, suggestive of a HCC recurrence with a direct extension to the biliary tract was found. Finally a biliary tumor obstruction has been developed and a percutaneous transhepatic biliary drainage was performed. This case of biliary obstruction caused by directly invaded recurred HCC after PRFA will be reported because of its rare occurrence.

  16. Image-guided ablation of painful metastatic bone tumors: a new and effective approach to a difficult problem

    International Nuclear Information System (INIS)

    Callstrom, Matthew R.; Charboneau, J. William; Atwell, Thomas D.; Farrell, Michael A.; Welch, Timothy J.; Maus, Timothy P.; Goetz, Matthew P.; Rubin, Joseph

    2006-01-01

    Painful skeletal metastases are a common problem in cancer patients. Although external beam radiation therapy is the current standard of care for cancer patients who present with localized bone pain, 20-30% of patients treated with this modality do not experience pain relief, and few further options exist for these patients. For many patients with painful metastatic skeletal disease, analgesics remain the only alternative treatment option. Recently, image-guided percutaneous methods of tumor destruction have proven effective for treatment of this difficult problem. This review describes the application, limitations, and effectiveness of percutaneous ablative methods including ethanol, methyl methacrylate, laser-induced interstitial thermotherapy (LITT), cryoablation, and percutaneous radiofrequency ablation (RFA) for palliation of painful skeletal metastases. (orig.)

  17. [Thermal balloon endometrial ablation for dysfunctional uterine bleeding: technical aspects and results. A prospective cohort study of 152 cases].

    Science.gov (United States)

    Kdous, Moez; Jacob, Denis; Gervaise, Amélie; Risk, Elie; Sauvanet, Eric

    2008-05-01

    Thermal balloon endometrial ablation is a new operative technique recently proposed in the treatment of dysfunctional uterine bleeding. To evaluate the efficacy of thermal balloon endometrial ablation in the treatment of dysfunctional uterine bleeding, and to identify the possible predictive factors for a successful outcome. A prospective study was conducted including 152 patients with chronic abnormal uterine bleeding refractory to medical treatment. All patients were treated by thermal balloon endometrial ablation (Thermachoice, Gynecare) between January 1, 1996 and December 31, 2003. patients were included if their uterine cavities sounded to less than 12 cm and had undergone hysteroscopy, pelvic ultrasound and endometrial biopsie showing no structural or (pre) malignant endometrial abnormalities. A balloon catheter was placed through the cervix and after inflation in the endometrial cavity with 5% dextrose in water, was heated to 87 +/- 5 degrees C. No one required cervical dilatation. Balloon pressures were 160 to 170 mm Hg. All patients underwent 8 minutes of therapy. The average patient was 47 years (range: 30-62 years) and was followed for a mean of 3 years and 7 months (range: 6 months - 8 years). 31.6% of women reported amennorhea, 16.5% hypomenorrhea and 21% eumenorrhea. Menorrhagea persisted in 11.2% of patients. No intraoperative complications and minor postoperative morbidity occured in 10.5% of patients. Three prgnancy complicated by spontaneous abortions were reported after the treatment. A total of 78% of women reported overall satisfaction with the endometrial ablation procedure and 18% were dissatisfied. 17.8% of patients underwent hysterectomy within 1 to 5 years of balloon endometrial ablation. Increasing age and menopause were significantly associated with increased odds of success (p < 0.05). Thermal balloon endometrial ablation is a simple, easy, effective, and minimally invasive procedure in menhorragic women with no desire for further

  18. Heterogeneity in induced thermal resistance of rat tumor cell clones

    International Nuclear Information System (INIS)

    Tomasovic, S.P.; Rosenblatt, P.L.; Heitzman, D.

    1983-01-01

    Four 13762NF rat mammary adenocarcinoma clones were examined for their survival response to heating under conditions that induced transient thermal resistance (thermotolerance). Clones MTC and MTF7 were isolated from the subcutaneous locally growing tumor, whereas clones MTLn2 and MTLn3 were derived from spontaneous lung metastases. There was heterogeneity among these clones in thermotolerance induced by either fractionated 45 0 C or continuous 42 0 C heating, but the order of sensitivity was not necessarily the same. The clones developed thermal resistance at different rates and to different degrees within the same time intervals. There was heterogeneity between clones isolated from within either the primary site or metastatic lesions. However, clones derived from metastatic foci did not intrinsically acquire more or less thermotolerance to fractionated 45 0 C or continuous 42 0 C heating than did clones from the primary tumor. Further, there was no apparent relationship between any phenotypic properties that conferred more or less thermotolerance in vitro and any phenotypic properties that conferred enhanced metastatic success of these same clones by spontaneous (subcutaneous) or experimental (intravenous) routes in vivo. These tumor clones also differ in their karyotype, metastatic potential, cell surface features, sensitivity to x-irradiation and drugs, and ability to repair sublethal radiation damage. These results provide further credence to the concept that inherent heterogeneity within tumors may be as important in therapeutic success as other known modifiers of outcome such as site and treatment heterogeneity

  19. Thermal Ablation of Lung Tissue: In Vivo Experimental Comparison of Microwave and Radiofrequency

    International Nuclear Information System (INIS)

    Crocetti, Laura; Bozzi, Elena; Faviana, Pinuccia; Cioni, Dania; Della Pina, Clotilde; Sbrana, Alberto; Fontanini, Gabriella; Lencioni, Riccardo

    2010-01-01

    This study was designed to compare feasibility, safety, and effectiveness of microwave (MW) ablation versus radiofrequency (RF) ablation of lung tissue in a rabbit model. Twenty New Zealand White rabbits were submitted to MW (n = 10, group A) or RF ablation (n = 10, group B). The procedures were performed with a prototype MW ablation device with a 1.6-cm radiating section antenna (Valleylab MW Ablation System) and with a 2-cm exposed-tip RF electrode (Cool-tip RF Ablation System). At immediate computed tomography increase in density, maximum diameters (D1-D3) of ablation zones were measured and ablation volume was calculated. Histopathologic assessment was performed 3 and 7 days after the procedure. Technical success was achieved in nine of 10 rabbits in each group. One death occurred in group B. Complications included pneumothorax (group A, n = 4; group B, n = 4), abscess (group A, n = 1; group B, n = 1), and thoracic wall burn (group A, n = 4). No significant differences were demonstrated in attenuation increase (P = 0.73), dimensions (P = 0.28, 0.86, 0.06, respectively, comparing D1-D3) and volume (P = 0.17). At histopathology, ablation zones were similar, with septal necrosis, edema, hemorrhage, and peripheral lymphocytic infiltrate. Complete thrombosis of more than 90% of vessels up to 2 mm in diameter was depicted at the periphery of the ablation zone in group A specimens. In group B specimens, complete thrombosis was depicted in 20% of vessels. Feasibility and safety of MW and RF ablation are similar in a lung rabbit model. MW ablation produces a greater damage to peripheral small vessels inducing thrombosis.

  20. 3.0 T MR diffusion weighted imaging in the evaluation of radio-frequency ablation of the liver VX2 tumors

    International Nuclear Information System (INIS)

    Liu Yubao; Liang Changhong; Wang Qiushi; Xie Shufei; Yu Yuanxin; Liu Zaiyi; Zhang Zhonglin

    2010-01-01

    Objective: To evaluate 3.0 T MR DWI techniques in detecting the lesions of pre and post-radiofrequency ablation of the rabbit liver VX2 tumors. Methods: Twenty two New Zealand white rabbits were used in this experiment. Twenty tumor fragments were implanted into the livers of 20 rabbits respectively. Two normal rabbits were used as controls for radiofrequency ablation of the normal liver. 3. 0 T MR DWI was performed 14 to 21 days after tumor implantation (mean, 17 days) in the tumor-bearing animals. Radiofrequency ablation was performed in the 18 tumor-bearing animals and in the two healthy animals. 3.0 T MRI and DWI were performed 7 to 10 days after radiofrequency ablation (mean, 8 days). Pathology was obtained immediately after the completion of post radiofrequency ablation MR imaging. The MRI features and ADC values of pre- and post -radiofrequency ablation lesions in the livers with VX2 tumors and normal rabbits were analyzed and correlation was made with histopathologic findings. Analysis of variance repeated measures were performed in analyzing the differences among the ADC values of different tissues with the same b value. Results: All 20 rabbit liver models of VX2 tumors were constructed successfully. One rabbit died of anesthetic overdose, another one showed necrosis within the implanted tumor. All 18 untreated VX2 tumors had predominantly low or iso-signal intensity on T 1 WI and high signal intensity on T 2 WI. All 18 VX2 tumors and 2 normal rabbits were treated by radiofrequency ablation successfully. Lesions treated by Radiofrequency ablation displayed low signal intensity on T 1 WI, and high signal intensity on T 2 WI. Seven to 10 days after radiofrequency ablation, lesions varied from having low signal intensity to slightly increased signal intensity on T 1 WI, with areas of mixed (high, intermediate, and low) signal intensity. A peripheral rim of high signal intensity with varying thickness on T 2 WI correlated with granulation tissue, which

  1. Conformal Ablative Thermal Protection System for Planetary and Human Exploration Missions

    Science.gov (United States)

    Beck, R.; Arnold, J.; Gasch, M.; Stackpole, M.; Wercinski, R.; Venkatapathy, E.; Fan, W.; Thornton, J; Szalai, C.

    2012-01-01

    interest. The entry environment is not always guaranteed with a direct entry, and improving the entry systems robustness to a variety of environmental conditions could aid in reaching more varied landing sites. The National Research Council (NRC) Space Technology Roadmaps and Priorities report highlights six challenges and they are: 1) Mass to Surface, 2) Surface Access, 3) Precision Landing, 4) Surface Hazard Detection and Avoidance, 5) Safety and Mission Assurance, and 6) Affordability. In order for NASA to meet these challenges, the report recommends immediate focus on Rigid and Flexible Thermal Protection Systems. Rigid TPS systems such as Avcoat or SLA are honeycomb based and PICA is in the form of tiles. The honeycomb systems is manufactured using techniques that require filling of each (3/8 cell) by hand and within a limited amount of time once the ablative compound is mixed, all of the cells have to be filled and the entire heat-shield has to be cured. The tile systems such as PICA pose a different challenge as the mechanical strength characteristic and the manufacturing limitations require large number of small tiles with gap-fillers between the tiles. Recent investments in flexible ablative systems have given rise to the potential for conformal ablative TPS> A conformal TPS over a rigid aeroshell has the potential to solve a number of challenges faced by traditional rigid TPS materials.

  2. Near-real-time feedback control system for liver thermal ablations based on self-referenced temperature imaging

    International Nuclear Information System (INIS)

    Keserci, Bilgin M.; Kokuryo, Daisuke; Suzuki, Kyohei; Kumamoto, Etsuko; Okada, Atsuya; Khankan, Azzam A.; Kuroda, Kagayaki

    2006-01-01

    Our challenge was to design and implement a dedicated temperature imaging feedback control system to guide and assist in a thermal liver ablation procedure in a double-donut 0.5T open MR scanner. This system has near-real-time feedback capability based on a newly developed 'self-referenced' temperature imaging method using 'moving-slab' and complex-field-fitting techniques. Two phantom validation studies and one ex vivo experiment were performed to compare the newly developed self-referenced method with the conventional subtraction method and evaluate the ability of the feedback control system in the same MR scanner. The near-real-time feedback system was achieved by integrating the following primary functions: (1) imaging of the moving organ temperature; (2) on-line needle tip tracking; (3) automatic turn-on/off the heating devices; (4) a Windows operating system-based novel user-interfaces. In the first part of the validation studies, microwave heating was applied in an agar phantom using a fast spoiled gradient recalled echo in a steady state sequence. In the second part of the validation and ex vivo study, target visualization, treatment planning and monitoring, and temperature and thermal dose visualization with the graphical user interface of the thermal ablation software were demonstrated. Furthermore, MR imaging with the 'self-referenced' temperature imaging method has the ability to localize the hot spot in the heated region and measure temperature elevation during the experiment. In conclusion, we have demonstrated an interactively controllable feedback control system that offers a new method for the guidance of liver thermal ablation procedures, as well as improving the ability to assist ablation procedures in an open MR scanner

  3. Saline-enhanced radiofrequency thermal ablation of the lung: a feasibility study in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Min; Kim, Sang Won; Li, Chun Ai; Youk, Ji Hyun; Kim, Young Kon; Jin, Zhewu; Chung, Myoung Ja [Chonbuk National University Medical School, Jeonju (Korea, Republic of); Lee, Mi Suk [Yangi Hospital, Seoul (Korea, Republic of)

    2002-12-01

    To assess the feasibility and safety of CT-guided percutaneous transthoracic radiofrequency ablation (RFA) with saline infusion of pulmonary tissue in rabbits. Twenty-eight New Zealand White rabbits were divided into two groups: an RFA group (n=10) and a saline-enhanced RFA (SRFA) group (n=18). In the RFA group, percutaneous RFA of the lung was performed under CT guidance and using a 17-gauge internally cooled electrode. In the SRFA group, 1.5 ml of 0.9% saline was infused slowly through a 21-gauge, polyteflon-coated Chiba needle prior to and during RFA. Lesion size and the healing process were studied in rabbits sacrificed at times from the day following treatment to three weeks after, and any complications were noted. In the SRFA group, the mean diameter (12.5{+-}1.6 mm) of acute RF lesions was greater than that of RFA lesions (8.5{+-}1.4 mm) (p < .05). The complications arising in 12 cases were pneumothorax (n=8), thermal injury to the chest wall (n=2), hemothorax (n=1), and lung abscess (n=1). Although procedure-related complications tended to occur more frequently in the SRFA group (55.6%) than in the RFA group (20%), the difference was not statistically significant (p .11). Saline-enhanced RFA of pulmonary tissue in rabbits produces more extensive coagulation necrosis than conventional RFA procedures, without adding substantial risk of serious complications.

  4. Standard Test Method for Oxyacetylene Ablation Testing of Thermal Insulation Materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method covers the screening of ablative materials to determine the relative thermal insulation effectiveness when tested as a flat panel in an environment of a steady flow of hot gas provided by an oxyacetylene burner. 1.2 This test method should be used to measure and describe the properties of materials, products, or assemblies in response to heat and flame under controlled laboratory conditions and should not be used to describe or appraise the fire hazard of materials, products, or assemblies under actual fire conditions. However, results of this test method may be used as elements of a fire risk assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard of a particular end use. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limi...

  5. Laser thermal ablation of multidrug-resistant bacteria using functionalized gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Mocan L

    2017-03-01

    Full Text Available Lucian Mocan,1,2 Flaviu A Tabaran,3 Teodora Mocan,2,4 Teodora Pop,5 Ofelia Mosteanu,5 Lucia Agoston-Coldea,6 Cristian T Matea,2 Diana Gonciar,2 Claudiu Zdrehus,1,2 Cornel Iancu1 13rd Department of General Surgery, “Iuliu Hatieganu” University of Medicine and Pharmacy, 2Department of Nanomedicine, “Octavian Fodor” Gastroenterology Institute, 3Department of Pathology, University of Agricultural Sciences and Veterinary Medicine, Faculty of Veterinary Medicine, 4Department of Physiology, 53rd Gastroenterology Department, 6Department of Internal Medicine, “Iuliu Hatieganu” University of Medicine and Pharmacy, Cluj-Napoca, Romania Abstract: The issue of multidrug resistance (MDR has become an increasing threat to public health. One alternative strategy against MDR bacteria would be to construct therapeutic vectors capable of physically damaging these microorganisms. Gold nanoparticles hold great promise for the development of such therapeutic agents, since the nanoparticles exhibit impressive properties, of which the most important is the ability to convert light into heat. This property has scientific significance since is exploited to develop nano-photothermal vectors to destroy bacteria at a molecular level. The present paper summarizes the latest advancements in the field of nanotargeted laser hyperthermia of MDR bacteria mediated by gold nanoparticles. Keywords: bacteria, photo-thermal ablation, gold nanoparticles, antibiotic resistance

  6. Stress (Tako-Tsubo) Cardiomyopathy Following Radiofrequency Ablation of a Liver Tumor: A Case Report

    International Nuclear Information System (INIS)

    Joo, Ijin; Lee, Jeong Min; Han, Joon Koo; Choi, Byung Ihn; Park, Eun-Ah

    2011-01-01

    Stress cardiomyopathy is characterized by transient left ventricular dysfunction occurring in the absence of obstructive coronary disease. It is precipitated by acute emotional or physical stress. We present a case of stress cardiomyopathy which developed during hepatic radiofrequency ablation of hepatocellular carcinoma.

  7. US-guided percutaneous radiofrequency thermal ablation for the treatment of solid benign hyperfunctioning or compressive thyroid nodules.

    Science.gov (United States)

    Deandrea, Maurilio; Limone, Paolo; Basso, Edoardo; Mormile, Alberto; Ragazzoni, Federico; Gamarra, Elena; Spiezia, Stefano; Faggiano, Antongiulio; Colao, Annamaria; Molinari, Filippo; Garberoglio, Roberto

    2008-05-01

    The aim of the study was to define the effectiveness and safety of ultrasound-guided percutaneous radiofrequency (RF) thermal ablation in the treatment of compressive solid benign thyroid nodules. Thirty-one patients not eligible for surgery or radioiodine (131I) treatment underwent RF ablation for benign nodules; a total of 33 nodules were treated (2 patients had 2 nodules treated in the same session): 10 cold nodules and 23 hyperfunctioning. Fourteen patients complained of compressive symptoms. Nodule volume, thyroid function and compressive symptoms were evaluated before treatment and at 1, 3 and 6 mo. Ultrasound-guided RF ablation was performed using a Starbust RITA needle, with nine expandable prongs; total exposure time was 6 to 10 min at 95 degrees C in one area or more of the nodule. Baseline volume (measured at the time of RF ablation) was 27.7 +/- 21.5 mL (mean +/- SD), but significantly decreased during follow-up: 19.2 +/- 16.2 at 1 mo (-32.7%; p nodules remained euthyroid: five patients with hot nodules normalized thyroid function, and the remaining sixteen showed a partial remission of hyperthyroidism. Besides a sensation of heat and mild swelling of the neck, no major complications were observed. Improvement in compressive symptoms was reported by 13 patients, with a reduction on severity scale from 6.1 +/- 1.4 to 2.2 +/- 1.9 (p nodules. Hyperfunction was fully controlled in 24% of patients and partially reduced in the others.

  8. Dual-energy computed tomography to assess tumor response to hepatic radiofrequency ablation: potential diagnostic value of virtual noncontrast images and iodine maps.

    Science.gov (United States)

    Lee, Su Hyun; Lee, Jeong Min; Kim, Kyung Won; Klotz, Ernst; Kim, Se Hyung; Lee, Jae Young; Han, Joon Koo; Choi, Byung Ihn

    2011-02-01

    to determine the value of dual-energy (DE) scanning with virtual noncontrast (VNC) images and iodine maps in the evaluation of therapeutic response to radiofrequency ablation (RFA) for hepatic tumors. a total of 75 patients with hepatic tumors and who underwent DE computed tomography (CT) after RFA, were enrolled in this study. Our DE CT protocol included precontrast, arterial, and portal phase scans. VNC images and iodine maps were created from 80 to 140 kVp images during the arterial and portal phases. VNC images were then compared with true, noncontrast (TNC) images, and iodine maps were compared with linearly blended images, both qualitatively and quantitatively. For the former comparison, image quality and acceptability of the VNC images as a replacement for TNC images were both rated. The CT numbers of the hepatic parenchyma, ablation zone, and image noise were measured. For the latter comparison, lesion conspicuity of the ablation zone and the additional benefit of integrating the iodine map into the routine protocol, were assessed. Contrast-to-noise ratios (CNR) of the ablation zone-to-liver and aorta-to-liver as well as the CT number differences between the center and the periphery of the ablation zone were calculated. The image quality of the VNC images was rated as good (mean grading score, 1.88) and the level of acceptance was 90% (68/75). The mean CT numbers of the hepatic parenchyma and ablation zone did not differ significantly between the TNC and the VNC images (P > 0.05). The lesion conspicuity of the ablation zone was rated as excellent or good in 97% of the iodine map (73/75), and the additional benefits of the iodine maps were positively rated as better to the same (mean 1.5). The CNR of the aorta-to-liver parenchyma was significantly higher on the iodine map (P = 0.002), and the CT number differences between the center and the periphery of the ablation zone were significantly lower on the iodine map (P VNC images can be an alternative to TNC

  9. Nanodrug-enhanced radiofrequency tumor ablation: effect of micellar or liposomal carrier on drug delivery and treatment efficacy.

    Directory of Open Access Journals (Sweden)

    Marwan Moussa

    Full Text Available To determine the effect of different drug-loaded nanocarriers (micelles and liposomes on delivery and treatment efficacy for radiofrequency ablation (RFA combined with nanodrugs.Fischer 344 rats were used (n = 196. First, single subcutaneous R3230 tumors or normal liver underwent RFA followed by immediate administration of i.v. fluorescent beads (20, 100, and 500 nm, with fluorescent intensity measured at 4-24 hr. Next, to study carrier type on drug efficiency, RFA was combined with micellar (20 nm or liposomal (100 nm preparations of doxorubicin (Dox; targeting HIF-1α or quercetin (Qu; targeting HSP70. Animals received RFA alone, RFA with Lipo-Dox or Mic-Dox (1 mg i.v., 15 min post-RFA, and RFA with Lipo-Qu or Mic-Qu given 24 hr pre- or 15 min post-RFA (0.3 mg i.v.. Tumor coagulation and HIF-1α or HSP70 expression were assessed 24 hr post-RFA. Third, the effect of RFA combined with i.v. Lipo-Dox, Mic-Dox, Lipo-Qu, or Mic-Qu (15 min post-RFA compared to RFA alone on tumor growth and animal endpoint survival was evaluated. Finally, drug uptake was compared between RFA/Lipo-Dox and RFA/Mic-Dox at 4-72 hr.Smaller 20 nm beads had greater deposition and deeper tissue penetration in both tumor (100 nm/500 nm and liver (100 nm (p<0.05. Mic-Dox and Mic-Qu suppressed periablational HIF-1α or HSP70 rim thickness more than liposomal preparations (p<0.05. RFA/Mic-Dox had greater early (4 hr intratumoral doxorubicin, but RFA/Lipo-Dox had progressively higher intratumoral doxorubicin at 24-72 hr post-RFA (p<0.04. No difference in tumor growth and survival was seen between RFA/Lipo-Qu and RFA/Mic-Qu. Yet, RFA/Lipo-Dox led to greater animal endpoint survival compared to RFA/Mic-Dox (p<0.03.With RF ablation, smaller particle micelles have superior penetration and more effective local molecular modulation. However, larger long-circulating liposomal carriers can result in greater intratumoral drug accumulation over time and reduced tumor growth. Accordingly

  10. Percutaneous Thermal Ablation with Ultrasound Guidance. Fusion Imaging Guidance to Improve Conspicuity of Liver Metastasis

    Energy Technology Data Exchange (ETDEWEB)

    Hakime, Antoine, E-mail: thakime@yahoo.com; Yevich, Steven; Tselikas, Lambros; Deschamps, Frederic [Gustave Roussy - Cancer Campus, Interventional Radiology Department (France); Petrover, David [Imagerie Médicale Paris Centre, IMPC (France); Baere, Thierry De [Gustave Roussy - Cancer Campus, Interventional Radiology Department (France)

    2017-05-15

    PurposeTo assess whether fusion imaging-guided percutaneous microwave ablation (MWA) can improve visibility and targeting of liver metastasis that were deemed inconspicuous on ultrasound (US).Materials and MethodsMWA of liver metastasis not judged conspicuous enough on US was performed under CT/US fusion imaging guidance. The conspicuity before and after the fusion imaging was graded on a five-point scale, and significance was assessed by Wilcoxon test. Technical success, procedure time, and procedure-related complications were evaluated.ResultsA total of 35 patients with 40 liver metastases (mean size 1.3 ± 0.4 cm) were enrolled. Image fusion improved conspicuity sufficiently to allow fusion-targeted MWA in 33 patients. The time required for image fusion processing and tumors’ identification averaged 10 ± 2.1 min (range 5–14). Initial conspicuity on US by inclusion criteria was 1.2 ± 0.4 (range 0–2), while conspicuity after localization on fusion imaging was 3.5 ± 1 (range 1–5, p < 0.001). Technical success rate was 83% (33/40) in intention-to-treat analysis and 100% in analysis of treated tumors. There were no major procedure-related complications.ConclusionsFusion imaging broadens the scope of US-guided MWA to metastasis lacking adequate conspicuity on conventional US. Fusion imaging is an effective tool to increase the conspicuity of liver metastases that were initially deemed non visualizable on conventional US imaging.

  11. Radiofrequency ablation, an effective modality of treatment in tumor-induced osteomalacia: a case series of three patients.

    Science.gov (United States)

    Jadhav, Swati; Kasaliwal, Rajeev; Shetty, Nitin S; Kulkarni, Suyash; Rathod, Krantikumar; Popat, Bhavesh; Kakade, Harshal; Bukan, Amol; Khare, Shruti; Budyal, Sweta; Jagtap, Varsha S; Lila, Anurag R; Bandgar, Tushar; Shah, Nalini S

    2014-09-01

    Tumor-induced osteomalacia is curable if the tumors can be totally excised. However, when the tumors are present in locations that make surgery disproportionately risky, the need for less invasive strategies like radiofrequency ablation (RFA) is realized. We describe three patients with suspected tumor-induced osteomalacia who were treated in our department between 2006 and 2013 with tumors in surgically difficult locations and were subjected to single or multiple sessions of RFA. The response was documented in terms of symptomatic improvement, phosphorus normalization, and follow-up (99m)Technitium-labelled hydrazinonicotinyl-Tyr3-octreotide ((99m)Tc HYNIC TOC) scan. Two of the three individuals, patient A (with a 1.5 × 1.2-cm lesion in the head of the right femur) and patient B (with a 1.3 × 1.2-cm lesion on the endosteal surface of the shaft of the left femur), achieved complete remission with single sessions of RFA. Three months after the procedure, (99m)Tc HYNIC TOC scans revealed the absence of uptake at the previous sites, corroborating with the clinical improvement and phosphorus normalization. Patient C had a large 5.6 × 6.5-cm complex lesion in the lower end of the left femur with irregular margins, loculations, and bone grafts placed in previous surgery. He failed to achieve remission after multiple sessions of RFA due to the complex nature of the lesion, although the tumor burden was reduced significantly as documented on serial (99m)Tc HYNIC TOC scans. Although surgery remains the treatment of choice, RFA could be an effective, less invasive, and safe modality of treatment in judiciously selected patients.

  12. Experimental and clinical studies with radiofrequency-induced thermal endometrial ablation for functional menorrhagia

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, J.H.; Lewis, B.V.; Prior, M.V.; Roberts, T. (Watford General Hospital, Herts (England))

    1990-11-01

    A method of ablating the endometrium has been introduced into clinical practice that uses radiofrequency electromagnetic energy to heat the endometrium, using a probe inserted through the cervix. Preliminary studies suggest that over 80% of patients treated will develop either amenorrhea or a significant reduction in flow. The advantages of radiofrequency endometrial ablation over laser ablation or resection are the avoidance of intravascular fluid absorption, simplicity (no special operative hysteroscopic skills are required), speed of operation, and reduced cost compared with the Nd:YAG laser. In this paper, we describe the experimental studies performed during development of this new technique.

  13. Radiofrequency thermal ablation for pain control in patients with single painful bone metastasis from hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Carrafiello, Gianpaolo [Department of Radiology, Vascular and Interventional Radiology, University of Insubria, 21100 Varese (Italy)], E-mail: gcarraf@tin.it; Lagana, Domenico [Department of Radiology, Vascular and Interventional Radiology, University of Insubria, 21100 Varese (Italy)], E-mail: donlaga@gmail.com; Ianniello, Andrea [Department of Radiology, Vascular and Interventional Radiology, University of Insubria, 21100 Varese (Italy)], E-mail: ianand@libero.it; Nicotera, Paolo [Department of Radiology, Vascular and Interventional Radiology, University of Insubria, 21100 Varese (Italy)], E-mail: paolonicotera@virgilio.it; Fontana, Federico [Department of Radiology, Vascular and Interventional Radiology, University of Insubria, 21100 Varese (Italy)], E-mail: fede.fontana@libero.it; Dizonno, Massimiliano [Department of Radiology, Vascular and Interventional Radiology, University of Insubria, 21100 Varese (Italy)], E-mail: massimilianodizonno@libero.it; Cuffari, Salvatore [Service of Anaesthesiology and Palliative Care, University of Insubria, 21100 Varese (Italy)], E-mail: salvatore.cuffari@libero.it; Fugazzola, Carlo [Department of Radiology, Vascular and Interventional Radiology, University of Insubria, 21100 Varese (Italy)], E-mail: carlo.fugazzola@ospedale.varese.it

    2009-08-15

    Objective: The aim of this study was to assess the safety and the efficacy of radiofrequency thermal ablation (RFA) for pain relief and analgesics use reduction in two patients with painful bone metastases from hepatocellular carcinoma (HCC). Materials and methods: Two patients with lytic metastases from HCC located at the left superior ileo-pubic branch and at the middle arch of VII rib, performed RFA displacing a LeVeen Needle (3.5 and 4.0 cm diameter) under US (ultrasonography) and fluoroscopic guidance. Two methods were used to determine the response of both patients: the first method was to measure patient's worst pain with a Brief Pain Inventory (BPI) 1 day after the procedure, every week for 1 month, and thereafter at week 8 and 12 (total follow-up 3 months); Second method was to evaluate patient's analgesics use recorded at week 1, 4, 8 and 12. Analgesic medication use was translated into a morphine-equivalent dose. Results: The RFA were well tolerated by the patients who did not develop any complication. Both patients obtained substantial reduction of pain, which decreased from a mean score of 8 to approximately 2 in 4 weeks. In both patients we observed a reduction in the use of morphine dose-equivalent after a peak at week 1. CT (computed tomography) imaging, performed at 1 month after RFA, demonstrated that both procedures were technically successful and safe because consistent necrosis and no evidence for complications were observed. Conclusion: RFA provides a potential alternative method for palliation of painful osteolytic metastases from HCC; the procedure is safe, and the pain relief is substantial.

  14. Radiofrequency thermal ablation for pain control in patients with single painful bone metastasis from hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Carrafiello, Gianpaolo; Lagana, Domenico; Ianniello, Andrea; Nicotera, Paolo; Fontana, Federico; Dizonno, Massimiliano; Cuffari, Salvatore; Fugazzola, Carlo

    2009-01-01

    Objective: The aim of this study was to assess the safety and the efficacy of radiofrequency thermal ablation (RFA) for pain relief and analgesics use reduction in two patients with painful bone metastases from hepatocellular carcinoma (HCC). Materials and methods: Two patients with lytic metastases from HCC located at the left superior ileo-pubic branch and at the middle arch of VII rib, performed RFA displacing a LeVeen Needle (3.5 and 4.0 cm diameter) under US (ultrasonography) and fluoroscopic guidance. Two methods were used to determine the response of both patients: the first method was to measure patient's worst pain with a Brief Pain Inventory (BPI) 1 day after the procedure, every week for 1 month, and thereafter at week 8 and 12 (total follow-up 3 months); Second method was to evaluate patient's analgesics use recorded at week 1, 4, 8 and 12. Analgesic medication use was translated into a morphine-equivalent dose. Results: The RFA were well tolerated by the patients who did not develop any complication. Both patients obtained substantial reduction of pain, which decreased from a mean score of 8 to approximately 2 in 4 weeks. In both patients we observed a reduction in the use of morphine dose-equivalent after a peak at week 1. CT (computed tomography) imaging, performed at 1 month after RFA, demonstrated that both procedures were technically successful and safe because consistent necrosis and no evidence for complications were observed. Conclusion: RFA provides a potential alternative method for palliation of painful osteolytic metastases from HCC; the procedure is safe, and the pain relief is substantial.

  15. Non-thermal effects on femtosecond laser ablation of polymers extracted from the oscillation of time-resolved reflectivity

    Energy Technology Data Exchange (ETDEWEB)

    Kumada, Takayuki, E-mail: kumada.takayuki@jaea.go.jp; Akagi, Hiroshi; Itakura, Ryuji; Otobe, Tomohito; Nishikino, Masaharu; Yokoyama, Atsushi [Kansai Photon Science Institute, Japan Atomic Energy Agency, Umemidai, Kizugawa, Kyoto 619-0215 (Japan)

    2015-06-01

    The dynamics of femtosecond laser ablation of transparent polymers were examined using time-resolved reflectivity. When these polymers were irradiated by a pump pulse with fluence above the ablation threshold of 0.8–2.0 J/cm{sup 2}, we observed the oscillation of the reflectivity caused by the interference between the reflected probe pulses from the sample surface and the thin layer due to the non-thermal photomechanical effects of spallation. As the fluence of the pump pulse increased, the separation velocity of the thin layer increased from 6 km/s to the asymptotic value of 11 km/s. It is suggested that the velocities are determined by shock-wave velocities of the photo-excited layer.

  16. Phase I/II Study of Radiofrequency Ablation for Malignant Renal Tumors: Japan Interventional Radiology in Oncology Study Group 0701

    Energy Technology Data Exchange (ETDEWEB)

    Mimura, Hidefumi, E-mail: mimura@marianna-u.ac.jp [St. Marianna University School of Medicine, Department of Radiology (Japan); Arai, Yasuaki, E-mail: arai-y3111@mvh.biglobe.ne.jp [National Cancer Center Hospital, Department of Diagnostic Radiology (Japan); Yamakado, Koichiro, E-mail: yama@clin.medic.mie-u.ac.jp [Mie University School of Medicine, Department of Interventional Radiology (Japan); Sone, Miyuki, E-mail: msone@me.com; Takeuchi, Yoshito, E-mail: yotake62@qg8.so-net.ne.jp [National Cancer Center Hospital, Department of Diagnostic Radiology (Japan); Miki, Tsuneharu, E-mail: tmiki@koto.kpu-m.ac.jp [Kyoto Prefectural University of Medicine, Department of Urology (Japan); Gobara, Hideo, E-mail: gobara@cc.okayama-u.ac.jp [Okayama University Medical School, Department of Radiology (Japan); Sakuhara, Yusuke, E-mail: yusaku@med.hokudai.ac.jp [Hokkaido University School of Medicine, Department of Diagnostic and Interventional Radiology (Japan); Yamamoto, Takanobu, E-mail: tyamamot@tcc.pref.tochigi.lg.jp [Tochigi Cancer Center, Department of Radiology (Japan); Sato, Yozo, E-mail: ysato@aichi-cc.jp [Aichi Cancer Center Hospital, Department of Diagnostic and Interventional Radiology (Japan); Kanazawa, Susumu, E-mail: susumu@cc.okayama-u.ac.jp [Okayama University Medical School, Department of Radiology (Japan)

    2016-05-15

    PurposeThis multicenter phase I/II study evaluated the safety, feasibility, and initial efficacy of radiofrequency ablation (RFA) for small malignant renal tumors.MethodsThirty-three patients were enrolled in the study. A single session of RFA was performed in patients with a renal tumor of 1–3 cm in greatest diameter, with the exception of lesions adjacent to the renal hilum. The primary endpoint was the safety of renal RFA, and the secondary endpoints were its feasibility and initial efficacy for local control, as well as the incidence and grade of adverse events. Clinical efficacy was evaluated by CT scans within 1 week and at a further 4 weeks after the procedure using the criteria adapted from the Response Evaluation Criteria in Solid Tumors.ResultsThe RFA procedure was completed in 100 % (95 % confidence interval [CI] 89–100 %) of all 33 patients. There were no severe adverse events (0 % [95 % CI 0–11 %]). Among the 33 patients, a complete response, partial response, progressive disease, and stable disease were seen in 28 (85 %), 0 (0 %), one (3 %), and one (3 %) patient(s), respectively, with a tumor response rate of 85 % [95 % CI 68–95 %]). Three patients (9 %), including one ineligible patient (3 %), were not evaluable. Out of 30 evaluable patients, a complete response was achieved in 28 (93 %).ConclusionThe current multicenter trial revealed that RFA is a safe, feasible, and effective treatment for small malignant renal tumors in patients who are not candidates for surgery.

  17. Phase I/II Study of Radiofrequency Ablation for Malignant Renal Tumors: Japan Interventional Radiology in Oncology Study Group 0701

    International Nuclear Information System (INIS)

    Mimura, Hidefumi; Arai, Yasuaki; Yamakado, Koichiro; Sone, Miyuki; Takeuchi, Yoshito; Miki, Tsuneharu; Gobara, Hideo; Sakuhara, Yusuke; Yamamoto, Takanobu; Sato, Yozo; Kanazawa, Susumu

    2016-01-01

    PurposeThis multicenter phase I/II study evaluated the safety, feasibility, and initial efficacy of radiofrequency ablation (RFA) for small malignant renal tumors.MethodsThirty-three patients were enrolled in the study. A single session of RFA was performed in patients with a renal tumor of 1–3 cm in greatest diameter, with the exception of lesions adjacent to the renal hilum. The primary endpoint was the safety of renal RFA, and the secondary endpoints were its feasibility and initial efficacy for local control, as well as the incidence and grade of adverse events. Clinical efficacy was evaluated by CT scans within 1 week and at a further 4 weeks after the procedure using the criteria adapted from the Response Evaluation Criteria in Solid Tumors.ResultsThe RFA procedure was completed in 100 % (95 % confidence interval [CI] 89–100 %) of all 33 patients. There were no severe adverse events (0 % [95 % CI 0–11 %]). Among the 33 patients, a complete response, partial response, progressive disease, and stable disease were seen in 28 (85 %), 0 (0 %), one (3 %), and one (3 %) patient(s), respectively, with a tumor response rate of 85 % [95 % CI 68–95 %]). Three patients (9 %), including one ineligible patient (3 %), were not evaluable. Out of 30 evaluable patients, a complete response was achieved in 28 (93 %).ConclusionThe current multicenter trial revealed that RFA is a safe, feasible, and effective treatment for small malignant renal tumors in patients who are not candidates for surgery.

  18. Is Antibiotic Prophylaxis for Percutaneous Radiofrequency Ablation (RFA) of Primary Liver Tumors Necessary? Results From a Single-Center Experience

    International Nuclear Information System (INIS)

    Bhatia, Shivank S.; Spector, Seth; Echenique, Ana; Froud, Tatiana; Suthar, Rekha; Lawson, Ivy; Dalal, Ravi; Dinh, Vy; Yrizarry, Jose; Narayanan, Govindarajan

    2015-01-01

    PurposeThe purpose of this study was to evaluate need for antibiotic prophylaxis for radiofrequency ablation (RFA) of liver tumors in patients with no significant co-existing risk factors for infection.Materials and MethodsFrom January 2004 to September 2013, 83 patients underwent 123 percutaneous RFA procedures for total of 152 hepatocellular carcinoma (HCC) lesions. None of the patients had pre-existing biliary enteric anastomosis (BEA) or any biliary tract abnormality predisposing to ascending biliary infection or uncontrolled diabetes mellitus. No pre- or post-procedure antibiotic prophylaxis was provided for 121 procedures. Data for potential risk factors were reviewed retrospectively and analyzed for the frequency of infectious complications, including abscess formation.ResultsOne patient (1/121 (0.8 %) RFA sessions) developed a large segment 5 liver abscess/infected biloma communicating with the gallbladder 7 weeks after the procedure, successfully treated over 10 weeks with IV and PO antibiotic therapy and percutaneous catheter drainage. This patient did not receive any antibiotics prior to RFA. During the procedure, there was inadvertent placement of RFA probe tines into the gallbladder. No other infectious complications were documented.ConclusionThese data suggest that the routine use of prophylactic antibiotics for liver RFA is not necessary in majority of the patients undergoing liver ablation for HCC and could be limited to patients with high-risk factors such as the presence of BEA or other biliary abnormalities, uncontrolled diabetes mellitus, and large centrally located tumors in close proximity to central bile ducts. Larger randomized studies are needed to confirm this hypothesis

  19. Is Antibiotic Prophylaxis for Percutaneous Radiofrequency Ablation (RFA) of Primary Liver Tumors Necessary? Results From a Single-Center Experience

    Energy Technology Data Exchange (ETDEWEB)

    Bhatia, Shivank S., E-mail: sbhatia1@med.miami.edu [University of Miami, Vascular/Interventional Radiology, Department of Radiology, Miller School of Medicine (United States); Spector, Seth, E-mail: sspector@med.miami.edu [University of Miami, Department of Surgery, VA Hospital (Veterans Affairs Medical Center) (United States); Echenique, Ana, E-mail: aechenique@med.miami.edu; Froud, Tatiana, E-mail: tfroud@med.miami.edu; Suthar, Rekha, E-mail: rsuthar@med.miami.edu; Lawson, Ivy, E-mail: i.lawson1@med.miami.edu; Dalal, Ravi, E-mail: rdalal@med.miami.edu [University of Miami, Vascular/Interventional Radiology, Department of Radiology, Miller School of Medicine (United States); Dinh, Vy, E-mail: vdinh@med.miami.edu [VA Hospital (Veterans Affairs Medical Center), Department of Medicine (United States); Yrizarry, Jose, E-mail: jyrizarr@med.miami.edu; Narayanan, Govindarajan, E-mail: gnarayanan@med.miami.edu [University of Miami, Vascular/Interventional Radiology, Department of Radiology, Miller School of Medicine (United States)

    2015-08-15

    PurposeThe purpose of this study was to evaluate need for antibiotic prophylaxis for radiofrequency ablation (RFA) of liver tumors in patients with no significant co-existing risk factors for infection.Materials and MethodsFrom January 2004 to September 2013, 83 patients underwent 123 percutaneous RFA procedures for total of 152 hepatocellular carcinoma (HCC) lesions. None of the patients had pre-existing biliary enteric anastomosis (BEA) or any biliary tract abnormality predisposing to ascending biliary infection or uncontrolled diabetes mellitus. No pre- or post-procedure antibiotic prophylaxis was provided for 121 procedures. Data for potential risk factors were reviewed retrospectively and analyzed for the frequency of infectious complications, including abscess formation.ResultsOne patient (1/121 (0.8 %) RFA sessions) developed a large segment 5 liver abscess/infected biloma communicating with the gallbladder 7 weeks after the procedure, successfully treated over 10 weeks with IV and PO antibiotic therapy and percutaneous catheter drainage. This patient did not receive any antibiotics prior to RFA. During the procedure, there was inadvertent placement of RFA probe tines into the gallbladder. No other infectious complications were documented.ConclusionThese data suggest that the routine use of prophylactic antibiotics for liver RFA is not necessary in majority of the patients undergoing liver ablation for HCC and could be limited to patients with high-risk factors such as the presence of BEA or other biliary abnormalities, uncontrolled diabetes mellitus, and large centrally located tumors in close proximity to central bile ducts. Larger randomized studies are needed to confirm this hypothesis.

  20. A prospective development study of software-guided radio-frequency ablation of primary and secondary liver tumors: Clinical intervention modelling, planning and proof for ablation cancer treatment (ClinicIMPPACT

    Directory of Open Access Journals (Sweden)

    Martin Reinhardt

    2017-12-01

    Discussion: This unique multicenter clinical trial aims at the clinical integration of a dedicated software solution to accurately predict lesion size and shape after radiofrequency ablation of liver tumors. Accelerated and optimized workflow integration, and real-time intraoperative image processing, as well as inclusion of patient specific information, e.g. organ perfusion and registration of the real RFA needle position might make the introduced software a powerful tool for interventional radiologists to optimize patient outcomes.

  1. Investigation of the wavelength dependence of laser stratigraphy on Cu and Ni coatings using LIBS compared to a pure thermal ablation model

    Science.gov (United States)

    Paulis, Evgeniya; Pacher, Ulrich; Weimerskirch, Morris J. J.; Nagy, Tristan O.; Kautek, Wolfgang

    2017-12-01

    In this study, galvanic coatings of Cu and Ni, typically applied in industrial standard routines, were investigated. Ablation experiments were carried out using the first two harmonic wavelengths of a pulsed Nd:YAG laser and the resulting plasma spectra were analysed using a linear Pearson correlation method. For both wavelengths the absorption/ablation behaviour as well as laser-induced breakdown spectroscopy (LIBS) depth profiles were studied varying laser fluences between 4.3-17.2 J/cm^2 at 532 nm and 2.9-11.7 J/cm^2 at 1064 nm. The LIBS-stratigrams were compared with energy-dispersive X-ray spectroscopy of cross-sections. The ablation rates were calculated and compared to theoretical values originating from a thermal ablation model. Generally, higher ablation rates were obtained with 532 nm light for both materials. The light-plasma interaction is suggested as possible cause of the lower ablation rates in the infrared regime. Neither clear evidence of the pure thermal ablation, nor correlation with optical properties of investigated materials was obtained.

  2. Predictive factors of symptomatic radiation pneumonitis in primary and metastatic lung tumors treated with stereotactic ablative body radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kang Pyo; Lee, Jeong Shim; Cho, Yeona; Chung, Seung Yeun; Lee, Jason Joon Bock; Lee, Chang Geol; Cho, Jae Ho [Dept. of Radiation Oncology, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2017-06-15

    Although stereotactic ablative body radiotherapy (SABR) is widely used therapeutic technique, predictive factors of radiation pneumonitis (RP) after SABR remain undefined. We aimed to investigate the predictive factors affecting RP in patients with primary or metastatic lung tumors who received SABR. From 2012 to 2015, we reviewed 59 patients with 72 primary or metastatic lung tumors treated with SABR, and performed analyses of clinical and dosimetric variables related to symptomatic RP. SABR was delivered as 45–60 Gy in 3–4 fractions, which were over 100 Gy in BED when the α/β value was assumed to be 10. Tumor volume and other various dose volume factors were analyzed using median value as a cutoff value. RP was graded per the Common Terminology Criteria for Adverse Events v4.03. At the median follow-up period of 11 months, symptomatic RP was observed in 13 lesions (12 patients, 18.1%), including grade 2 RP in 11 lesions and grade 3 in 2 lesions. Patients with planning target volume (PTV) of ≤14.35 mL had significantly lower rates of symptomatic RP when compared to others (8.6% vs. 27%; p = 0.048). Rates of symptomatic RP in patients with internal gross tumor volume (iGTV) >4.21 mL were higher than with ≤4.21 mL (29.7% vs. 6.1%; p = 0.017). The incidence of symptomatic RP following treatment with SABR was acceptable with grade 2 RP being observed in most patients. iGTV over 4.21 mL and PTV of over 14.35 mL were significant predictive factors related to symptomatic RP.

  3. Magnetic resonance imaging after radiofrequency ablation in a rodent model of liver tumor: tissue characterization using a novel necrosis-avid contrast agent

    International Nuclear Information System (INIS)

    Ni, Yicheng; Yu, Jie; Marchal, Guy; Chen, Feng; Mulier, Stefaan; Sun, Xihe; Landuyt, Willy; Verbruggen, Alfons

    2006-01-01

    We exploited a necrosis-avid contrast agent ECIV-7 for magnetic resonance imaging (MRI) in rodent liver tumors after radiofrequency ablation (RFA). Rats bearing liver rhabdomyosarcoma (R1) were randomly allocated to three groups: group I, complete RFA, group II, incomplete RFA, and group III, sham ablation. Within 24 h after RFA, T1-weighted (T1-w) MRI was performed before and after injection of ECIV-7 at 0.05 mmol/kg and followed up from 6-24 h. Signal intensities (SIs) were measured with relative enhancement (RE) and contrast ratio (CR) calculated. The MRI findings were verified histomorphologically. On plain T1-w MRI the contrasts between normal liver, RFA lesion, residual and/or intact tumor were vague. Early after administration of ECIV-7, the liver SI was strongly enhanced (RE=40-50%), leaving the RFA lesion as a hypointense region in groups I and II. At delayed phase, two striking peri-ablational enhancement patterns appeared (RE=90% and CR=1.89%), i.e., ''O'' type of hyperintense rim in group I and ''C'' type of incomplete rim in group II. These MRI manifestations could be proven histologically. In this study, tissue components after RFA could be characterized with discernable contrasts by necrosis-avid contrast agent (NACA)-enhanced MRI, especially at delayed phase. This approach may prove useful for defining the ablated area and identifying residual tumor after RFA. (orig.)

  4. Percutaneous Image-guided radiofrequency ablation of tumors in inoperable patients - immediate complications and overall safety

    Directory of Open Access Journals (Sweden)

    Anubha Sahay

    2016-01-01

    Conclusions: Percutaneous image-guided RFA is an option in patients where most other tumor management modalities have been exhausted or rejected. RFA may not be free from side effects such as postablation syndrome, pain, and there may be other serious complications such as bleeding, but based on our observations, percutaneous image-guided RFA of tumors is a safe palliative and therapeutic treatment option.

  5. Percutaneous radiofrequency ablation of lung tumors: evaluation of the literature using evidence-based techniques.

    LENUS (Irish Health Repository)

    Chan, Victoria O

    2012-02-01

    PURPOSE: The aim of this study was to evaluate the literature for articles assessing radiofrequency ablation (RFA) for pulmonary malignancy. MATERIALS AND METHODS: The "bottom-up" approach to evidence-based practice was applied by 2 reviewers to the retrieval and appraisal of original research articles published on pulmonary RFA between 2002 and 2009. Primary lung cancer and pulmonary metastases data were analyzed separately. The relationship between the percentage of local recurrence rate and lesion size, patient age, follow-up duration, and time to local recurrence was assessed using Spearman\\'s rank correlation. Discrete time series were used to evaluate time trends. RESULTS: Secondary evidence yielded 1 review of 26 observational studies. Primary evidence yielded 46 studies that seemed suitable for detailed appraisal. A total of 2905 ablations were performed in 1584 patients. Eight studies evaluated primary lung cancers alone, 11 evaluated pulmonary metastases alone, 25 evaluated both, and 2 did not specify the histology. Results revealed trends toward increasing use of conscious sedation over general anesthesia, increasing use of multitined probes, decreasing size of nodule selection, and use of positron emission tomography\\/computed tomography as the optimal follow-up tool. Mean morbidity was 24.6%. The most prevalent side effects included pneumothorax (28.3%), pleural effusions (14.8%), and pain (14.1%). Procedure-related mortality ranged from 0 to 5.6, with an overall procedure-related mortality rate of 0.21%. There were 282 (12.2%) local recurrences occurring at a mean of 13 months. The mean overall survival rate was 59.4%, and the cancer-specific survival rate was 82.6%. CONCLUSIONS: This evidence-based practice review of pulmonary RFA shows it to be a promising treatment for pulmonary malignancy in carefully selected patient populations. Studies with higher levels of evidence, including case-control, prospective nonrandomized and randomized trials

  6. Comparing renal function preservation after laparoscopic radio frequency ablation assisted tumor enucleation and laparoscopic partial nephrectomy for clinical T1a renal tumor: using a 3D parenchyma measurement system.

    Science.gov (United States)

    Zhu, Liangsong; Wu, Guangyu; Huang, Jiwei; Wang, Jianfeng; Zhang, Ruiyun; Kong, Wen; Xue, Wei; Huang, Yiran; Chen, Yonghui; Zhang, Jin

    2017-05-01

    To compare the renal function preservation between laparoscopic radio frequency ablation assisted tumor enucleation and laparoscopic partial nephrectomy. Data were analyzed from 246 patients who underwent laparoscopic radio frequency ablation assisted tumor enucleation and laparoscopic partial nephrectomy for solitary cT1a renal cell carcinoma from January 2013 to July 2015. To reduce the intergroup difference, we used a 1:1 propensity matching analysis. The functional renal parenchyma volume preservation were measured preoperative and 12 months after surgery. The total renal function recovery and spilt GFR was compared. Multivariable logistic analysis was used for predictive factors for renal function decline. After 1:1 propensity matching, each group including 100 patients. Patients in the laparoscopic radio frequency ablation assisted tumor enucleation had a smaller decrease in estimate glomerular filtration rate at 1 day (-7.88 vs -20.01%, p renal parenchyma volume preservation (89.19 vs 84.27%, p renal parenchyma volume preservation, warm ischemia time and baseline renal function were the important independent factors in determining long-term functional recovery. The laparoscopic radio frequency ablation assisted tumor enucleation technology has unique advantage and potential in preserving renal parenchyma without ischemia damage compared to conventional laparoscopic partial nephrectomy, and had a better outcome, thus we recommend this technique in selected T1a patients.

  7. Use of radiofrequency ablation in benign thyroid nodules: a literature review and updates.

    Science.gov (United States)

    Wong, Kai-Pun; Lang, Brian Hung-Hin

    2013-01-01

    Successful thermal ablation using radiofrequency has been reported in various tumors including liver or kidney tumors. Nonsurgical minimally invasive ablative therapy such as radiofrequency ablation (RFA) has been reported to be a safe and efficient treatment option in managing symptomatic cold thyroid nodules or hyperfunctioning thyroid nodules. Pressure and cosmetic symptoms have been shown to be significantly improved both in the short and long terms after RFA. For hyperfunctioning thyroid nodules, RFA is indicated for whom surgery or radioiodine are not indicated or ineffective or for those who refuse surgery or radio-iodine. Improvement of thyroid function with decreased need for antithyroid medications has been reported. Complication rate is relatively low. By reviewing the current literature, we reported its efficacy and complications and compared the efficacy of RFA relative to other ablative options such as ethanol ablation and laser ablation.

  8. Use of Radiofrequency Ablation in Benign Thyroid Nodules: A Literature Review and Updates

    Directory of Open Access Journals (Sweden)

    Kai-Pun Wong

    2013-01-01

    Full Text Available Successful thermal ablation using radiofrequency has been reported in various tumors including liver or kidney tumors. Nonsurgical minimally invasive ablative therapy such as radiofrequency ablation (RFA has been reported to be a safe and efficient treatment option in managing symptomatic cold thyroid nodules or hyperfunctioning thyroid nodules. Pressure and cosmetic symptoms have been shown to be significantly improved both in the short and long terms after RFA. For hyperfunctioning thyroid nodules, RFA is indicated for whom surgery or radioiodine are not indicated or ineffective or for those who refuse surgery or radio-iodine. Improvement of thyroid function with decreased need for antithyroid medications has been reported. Complication rate is relatively low. By reviewing the current literature, we reported its efficacy and complications and compared the efficacy of RFA relative to other ablative options such as ethanol ablation and laser ablation.

  9. A prospective development study of software-guided radio-frequency ablation of primary and secondary liver tumors: Clinical intervention modelling, planning and proof for ablation cancer treatment (ClinicIMPPACT).

    Science.gov (United States)

    Reinhardt, Martin; Brandmaier, Philipp; Seider, Daniel; Kolesnik, Marina; Jenniskens, Sjoerd; Sequeiros, Roberto Blanco; Eibisberger, Martin; Voglreiter, Philip; Flanagan, Ronan; Mariappan, Panchatcharam; Busse, Harald; Moche, Michael

    2017-12-01

    Radio-frequency ablation (RFA) is a promising minimal-invasive treatment option for early liver cancer, however monitoring or predicting the size of the resulting tissue necrosis during the RFA-procedure is a challenging task, potentially resulting in a significant rate of under- or over treatments. Currently there is no reliable lesion size prediction method commercially available. ClinicIMPPACT is designed as multicenter-, prospective-, non-randomized clinical trial to evaluate the accuracy and efficiency of innovative planning and simulation software. 60 patients with early liver cancer will be included at four European clinical institutions and treated with the same RFA system. The preinterventional imaging datasets will be used for computational planning of the RFA treatment. All ablations will be simulated simultaneously to the actual RFA procedure, using the software environment developed in this project. The primary outcome measure is the comparison of the simulated ablation zones with the true lesions shown in follow-up imaging after one month, to assess accuracy of the lesion prediction. This unique multicenter clinical trial aims at the clinical integration of a dedicated software solution to accurately predict lesion size and shape after radiofrequency ablation of liver tumors. Accelerated and optimized workflow integration, and real-time intraoperative image processing, as well as inclusion of patient specific information, e.g. organ perfusion and registration of the real RFA needle position might make the introduced software a powerful tool for interventional radiologists to optimize patient outcomes.

  10. Nanopulse Stimulation (NPS Induces Tumor Ablation and Immunity in Orthotopic 4T1 Mouse Breast Cancer: A Review

    Directory of Open Access Journals (Sweden)

    Stephen J. Beebe

    2018-03-01

    Full Text Available Nanopulse Stimulation (NPS eliminates mouse and rat tumor types in several different animal models. NPS induces protective, vaccine-like effects after ablation of orthotopic rat N1-S1 hepatocellular carcinoma. Here we review some general concepts of NPS in the context of studies with mouse metastatic 4T1 mammary cancer showing that the postablation, vaccine-like effect is initiated by dynamic, multilayered immune mechanisms. NPS eliminates primary 4T1 tumors by inducing immunogenic, caspase-independent programmed cell death (PCD. With lower electric fields, like those peripheral to the primary treatment zone, NPS can activate dendritic cells (DCs. The activation of DCs by dead/dying cells leads to increases in memory effector and central memory T-lymphocytes in the blood and spleen. NPS also eliminates immunosuppressive cells in the tumor microenvironment and blood. Finally, NPS treatment of 4T1 breast cancer exhibits an abscopal effect and largely prevents spontaneous metastases to distant organs. NPS with fast rise–fall times and pulse durations near the plasma membrane charging time constant, which exhibits transient, high-frequency components (1/time = Hz, induce responses from mitochondria, endoplasmic reticulum, and nucleus. Such effects may be responsible for release of danger-associated molecular patterns, including ATP, calreticulin, and high mobility group box 1 (HMBG1 from 4T1-Luc cells to induce immunogenic cell death (ICD. This likely leads to immunity and the vaccine-like response. In this way, NPS acts as a unique onco-immunotherapy providing distinct therapeutic advantages showing possible clinical utility for breast cancers as well as for other malignancies.

  11. Moldable cork ablation material

    Science.gov (United States)

    1977-01-01

    A successful thermal ablative material was manufactured. Moldable cork sheets were tested for density, tensile strength, tensile elongation, thermal conductivity, compression set, and specific heat. A moldable cork sheet, therefore, was established as a realistic product.

  12. [Radiofrequency ablation as a palliative therapy option in ENT tumors: in vivo and in vitro testing].

    Science.gov (United States)

    Bucher, S; Hornung, J; Bonkowsky, V; Iro, H; Zenk, J

    2010-04-01

    High frequency thermotherapy (HFTT) is an established palliative therapy for hepatic malignancies. An in vivo and in vitro trial examined the preconditions for the application of HFTT with liquid-cooled wet electrodes for minimally invasive palliation of head and neck tumors. HFTT was applied with needle electrodes, cooled with isotonic saline solution, and a high-frequency generator (Elektrotom HiTT 106, Berchtold, Tuttlingen) to porcine tongue and narcotized, juvenile domestic pigs to the tongue and neck, and monitored in realtime by B-mode ultrasound. The direction of spread of the hyperthermic zone is well observed using ultrasound. Determining the direction of spread is not possible with cooled-tip electrode needles. Severe complications were not observed during the application. RFA with liquid-cooled needle applicators is not safely applicable for the therapy of head and neck tumors.

  13. Pulmonary ablation: a primer.

    Science.gov (United States)

    Roberton, Benjamin J; Liu, David; Power, Mark; Wan, John M C; Stuart, Sam; Klass, Darren; Yee, John

    2014-05-01

    Percutaneous image-guided thermal ablation is safe and efficacious in achieving local control and improving outcome in the treatment of both early stage non-small-cell lung cancer and pulmonary metastatic disease, in which surgical treatment is precluded by comorbidity, poor cardiorespiratory reserve, or unfavorable disease distribution. Radiofrequency ablation is the most established technology, but new thermal ablation technologies such as microwave ablation and cryoablation may offer some advantages. The use of advanced techniques, such as induced pneumothorax and the popsicle stick technique, or combining thermal ablation with radiotherapy, widens the treatment options available to the multidisciplinary team. The intent of this article is to provide the reader with a practical knowledge base of pulmonary ablation by concentrating on indications, techniques, and follow-up. Copyright © 2014 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

  14. The effect of pre-vertebroplasty tumor ablation using laser-induced thermotherapy on biomechanical stability and cement fill in the metastatic spine

    OpenAIRE

    Ahn, Henry; Mousavi, Payam; Chin, Lee; Roth, Sandra; Finkelstein, Joel; Vitken, Alex; Whyne, Cari

    2007-01-01

    A biomechanical study comparing simulated lytic vertebral metastases treated with laser-induced thermotherapy (LITT) and vertebroplasty versus vertebroplasty alone. To investigate the effect of tumor ablation using LITT prior to vertebroplasty on biomechanical stability and cement fill patterns in a standardized model of spinal metastatic disease. Vertebroplasty in the metastatic spine is aimed at reducing pain, but is associated with risk of cement extravasation in up to 10%. Six pairs of fr...

  15. Ball-in-ball ZrO2 nanostructure for simultaneous CT imaging and highly efficient synergic microwave ablation and tri-stimuli-responsive chemotherapy of tumors.

    Science.gov (United States)

    Long, Dan; Niu, Meng; Tan, Longfei; Fu, Changhui; Ren, Xiangling; Xu, Ke; Zhong, Hongshan; Wang, Jingzhuo; Li, Laifeng; Meng, Xianwei

    2017-06-29

    Combined thermo-chemotherapy displays outstanding synergically therapeutic efficiency when compared with standalone thermotherapy and chemotherapy. Herein, we developed a smart tri-stimuli-responsive drug delivery system involving X@BB-ZrO 2 NPs (X represents loaded IL, DOX, keratin and tetradecanol) based on novel ball-in-ball-structured ZrO 2 nanoparticles (BB-ZrO 2 NPs). The microwave energy conversion efficiency of BB-ZrO 2 NPs was 41.2% higher than that of traditional single-layer NPs due to the cooperative action of self-reflection and spatial confinement effect of the special two-layer hollow nanostructure. The tri-stimuli-responsive controlled release strategy indicate that integrated pH, redox and microwaves in single NPs based on keratin and tetradecanol could effectively enhance the specific controlled release of DOX. The release of DOX was only 8.1% in PBS with pH = 7.2 and GSH = 20 μM. However, the release could reach about 50% at the tumor site (pH = 5.5, GSH = 13 mM) under microwave ablation. The as-made X@BB-ZrO 2 NPs exhibited perfect synergic therapy effect of chemotherapy and microwave ablation both in subcutaneous tumors (H22 tumor-bearing mice) and deep tumors (liver transplantation VX2 tumor-bearing rabbit model). There was no recurrence and death in the X@BB-ZrO 2 + MW group during the therapy of subcutaneous tumors even on the 42 nd day. The growth rates in the deep tumor of the control, MW and X@BB-ZrO 2 + MW groups were 290.1%, 14.1% and -42% 6 days after ablation, respectively. Dual-source CT was used to monitor the metabolism behavior of the as-made BB-ZrO 2 NPs and traditional CT was utilized to monitor the tumor growth in rabbits. Frozen section examination and ICP results indicated the precise control of drug delivery and enhanced cytotoxicity by the tri-stimuli-responsive controlled release strategy. The ball-in-ball ZrO 2 NPs with high microwave energy conversion efficiency were first developed for synergic microwave ablation and

  16. Functional Outcomes of Multiple Sural Nerve Grafts for Facial Nerve Defects after Tumor-Ablative Surgery

    Directory of Open Access Journals (Sweden)

    Myung Chul Lee

    2015-07-01

    Full Text Available BackgroundFunctional restoration of the facial expression is necessary after facial nerve resection to treat head and neck tumors. This study was conducted to evaluate the functional outcomes of patients who underwent facial nerve cable grafting immediately after tumor resection.MethodsPatients who underwent cable grafting from April 2007 to August 2011 were reviewed, in which a harvested branch of the sural nerve was grafted onto each facial nerve division. Twelve patients underwent facial nerve cable grafting after radical parotidectomy, total parotidectomy, or schwannoma resection, and the functional facial expression of each patient was evaluated using the Facial Nerve Grading Scale 2.0. The results were analyzed according to patient age, follow-up duration, and the use of postoperative radiation therapy.ResultsAmong the 12 patients who were evaluated, the mean follow-up duration was 21.8 months, the mean age at the time of surgery was 42.8 years, and the mean facial expression score was 14.6 points, indicating moderate dysfunction. Facial expression scores were not influenced by age at the time of surgery, follow-up duration, or the use of postoperative radiation therapy.ConclusionsThe results of this study indicate that facial nerve cable grafting using the sural nerve can restore facial expression. Although patients were provided with appropriate treatment, the survival rate for salivary gland cancer was poor. We conclude that immediate facial nerve reconstruction is a worthwhile procedure that improves quality of life by allowing the recovery of facial expression, even in patients who are older or may require radiation therapy.

  17. Radiofrequency Thermal Ablation Heat Energy Transfer in an Ex-Vivo Model.

    Science.gov (United States)

    Thakur, Shivani; Lavito, Sandi; Grobner, Elizabeth; Grobner, Mark

    2017-12-01

    Little work has been done to consider the temperature changes and energy transfer that occur in the tissue outside the vein with ultrasound-guided vein ablation therapy. In this experiment, a Ex-Vivo model of the human calf was used to analyze heat transfer and energy degradation in tissue surrounding the vein during endovascular radiofrequency ablation (RFA). A clinical vein ablation protocol was used to determine the tissue temperature distribution in 10 per cent agar gel. Heat energy from the radiofrequency catheter was measured for 140 seconds at fixed points by four thermometer probes placed equidistant radially at 0.0025, 0.005, and 0.01 m away from the RFA catheter. The temperature rose 1.5°C at 0.0025 m, 0.6°C at 0.005 m, and 0.0°C at 0.01 m from the RFA catheter. There was a clinically insignificant heat transfer at the distances evaluated, 1.4 ± 0.2 J/s at 0.0025 m, 0.7 ± 0.3 J/s at 0.0050 m, and 0.3 ± 0.0 J/s at 0.01 m. Heat degradation occurred rapidly: 4.5 ± 0.5 J (at 0.0025 m), 4.0 ± 1.6 J (at 0.0050 m), and 3.9 ± 3.6 J (at 0.01 m). Tumescent anesthesia injected one centimeter around the vein would act as a heat sink to absorb the energy transferred outside the vein to minimize tissue and nerve damage and will help phlebologists strategize options for minimizing damage.

  18. Conformal Ablative Thermal Protection System for Planetary and Human Exploration Missions:An Overview of the Technology Maturation Effort

    Science.gov (United States)

    Beck, Robin A S.; Arnold, James O.; Gasch, Matthew J.; Stackpoole, Margaret M.; Prabhu, Dinesh K.; Szalai, Christine E.; Wercinski, Paul F.; Venkatapathy, Ethiraj

    2013-01-01

    The Office of Chief Technologist, NASA identified the need for research and technology development in part from NASAs Strategic Goal 3.3 of the NASA Strategic Plan to develop and demonstrate the critical technologies that will make NASAs exploration, science, and discovery missions more affordable and more capable. Furthermore, the Game Changing Development Program is a primary avenue to achieve the Agencys 2011 strategic goal to Create the innovative new space technologies for our exploration, science, and economic future. The National Research Council (NRC) Space Technology Roadmaps and Priorities report highlights six challenges and they are: Mass to Surface, Surface Access, Precision Landing, Surface Hazard Detection and Avoidance, Safety and Mission Assurance, and Affordability. In order for NASA to meet these challenges, the report recommends immediate focus on Rigid and Flexible Thermal Protection Systems. Rigid TPS systems such as Avcoat or SLA are honeycomb based and PICA is in the form of tiles. The honeycomb systems are manufactured using techniques that require filling of each (38 cell) by hand, and in a limited amount of time all of the cells must be filled and the heatshield must be cured. The tile systems such as PICA pose a different challenge as the low strain-to-failure and manufacturing size limitations require large number of small tiles with gap-fillers between the tiles. Recent investments in flexible ablative systems have given rise to the potential for conformal ablative TPS. A conformal TPS over a rigid aeroshell has the potential to solve a number of challenges faced by traditional rigid TPS materials. The high strain-to-failure nature of the conformal ablative materials will allow integration of the TPS with the underlying aeroshell structure much easier and enable monolithic-like configuration and larger segments (or parts) to be used. By reducing the overall part count, the cost of installation (based on cost comparisons between blanket

  19. Irreversible electroporation ablation (IRE of unresectable soft tissue tumors: learning curve evaluation in the first 150 patients treated.

    Directory of Open Access Journals (Sweden)

    Prejesh Philips

    Full Text Available BACKGROUND: Irreversible electroporation (IRE is a novel technology that uses peri-target discrete probes to deliver high-voltage localized electric current to induce cell death without thermal-induced coagulative necrosis. "Learnability" and consistently effective results by novice practitioners is essential for determining acceptance of novel techniques. This multi-center prospectively-collected database study evaluates the learning curve of IRE. METHODS: Analysis of 150 consecutive patients over 7 institutions from 9/2010-7/2012 was performed with patients treated divided into 3 groups A (1(st 50 patients treated, B (2(nd 50 and C (3(rd 50 patients treated chronologically and analyzed for outcomes. RESULTS: A total of 167 IRE procedures were performed, with a majority being liver(39.5% and pancreatic(35.5% lesions. The three groups were similar with respect to co-morbidities and demographics. Group C had larger lesions (3.9 vs 3 cm,p=0.001, more numerous lesions (3.2 vs 2.2,p=0.07, more vascular invasion(p=0.001, underwent more associated procedures(p=0.001 and had longer operative times(p<0.001. Despite this, they had similar complication and high-grade complication rates(p=0.24. Attributable morbidity rate was 13.3%(total 29.3% and high-grade complications were seen in 4.19%(total 12.6%. Pancreatic lesions(p=0.001 and laparotomy(p=0.001 were associated with complications. CONCLUSION: The review represents that single largest review of IRE soft tissue ablation demonstrating initial patient selection and safety. Over time, complex treatments of larger lesions and lesions with greater vascular involvement were performed without a significant increase in adverse effects or impact on local relapse free survival. This evolution demonstrates the safety profile of IRE and speed of graduation to more complex lesions, which was greater than 5 cases by institution. IRE is a safe and effective alternative to conventional ablation with a demonstrable

  20. Determinants of Local Progression After Computed Tomography-Guided Percutaneous Radiofrequency Ablation for Unresectable Lung Tumors: 9-Year Experience in a Single Institution

    International Nuclear Information System (INIS)

    Okuma, Tomohisa; Matsuoka, Toshiyuki; Yamamoto, Akira; Oyama, Yoshimasa; Hamamoto, Shinichi; Toyoshima, Masami; Nakamura, Kenji; Miki, Yukio

    2010-01-01

    The purpose of this study was to retrospectively determine the local control rate and contributing factors to local progression after computed tomography (CT)-guided radiofrequency ablation (RFA) for unresectable lung tumor. This study included 138 lung tumors in 72 patients (56 men and 16 women; age 70.0 ± 11.6 years (range 31-94); mean tumor size 2.1 ± 1.2 cm [range 0.2-9]) who underwent lung RFA between June 2000 and May 2009. Mean follow-up periods for patients and tumors were 14 and 12 months, respectively. The local progression-free rate and survival rate were calculated to determine the contributing factors to local progression. During follow-up, 44 of 138 (32%) lung tumors showed local progression. The 1-, 2-, 3-, and 5-year overall local control rates were 61, 57, 57, and 38%, respectively. The risk factors for local progression were age (≥70 years), tumor size (≥2 cm), sex (male), and no achievement of roll-off during RFA (P < 0.05). Multivariate analysis identified tumor size ≥2 cm as the only independent factor for local progression (P = 0.003). For tumors <2 cm, 17 of 68 (25%) showed local progression, and the 1-, 2-, and 3-year overall local control rates were 77, 73, and 73%, respectively. Multivariate analysis identified that age ≥70 years was an independent determinant of local progression for tumors <2 cm in diameter (P = 0.011). The present study showed that 32% of lung tumors developed local progression after CT-guided RFA. The significant risk factor for local progression after RFA for lung tumors was tumor size ≥2 cm.

  1. Non-invasive thermal IR detection of breast tumor development in vivo

    Science.gov (United States)

    Case, Jason R.; Young, Madison A.; Dréau, D.; Trammell, Susan R.

    2015-03-01

    Lumpectomy coupled with radiation therapy and/or chemotherapy comprises the treatment of breast cancer for many patients. We are developing an enhanced thermal IR imaging technique that can be used in real-time to guide tissue excision during a lumpectomy. This novel enhanced thermal imaging method is a combination of IR imaging (8- 10 μm) and selective heating of blood (~0.5 °C) relative to surrounding water-rich tissue using LED sources at low powers. Post-acquisition processing of these images highlights temporal changes in temperature and is sensitive to the presence of vascular structures. In this study, fluorescent and enhanced thermal imaging modalities were used to estimate breast cancer tumor volumes as a function of time in 19 murine subjects over a 30-day study period. Tumor volumes calculated from fluorescent imaging follow an exponential growth curve for the first 22 days of the study. Cell necrosis affected the tumor volume estimates based on the fluorescent images after Day 22. The tumor volumes estimated from enhanced thermal imaging show exponential growth over the entire study period. A strong correlation was found between tumor volumes estimated using fluorescent imaging and the enhanced IR images, indicating that enhanced thermal imaging is capable monitoring tumor growth. Further, the enhanced IR images reveal a corona of bright emission along the edges of the tumor masses. This novel IR technique could be used to estimate tumor margins in real-time during surgical procedures.

  2. Evaluation of hepatocellular carcinoma tumor vascularity using contrast-enhanced ultrasonography as a predictor for local recurrence following radiofrequency ablation

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Tomohiro [Gastroenterological Center, Yokohama City University Medical Center, 4-57 Urafune-cho, Minami-ku, Yokohama, Kanagawa 232-0024 (Japan); Numata, Kazushi, E-mail: kz-numa@urahp.yokohama-cu.ac.jp [Gastroenterological Center, Yokohama City University Medical Center, 4-57 Urafune-cho, Minami-ku, Yokohama, Kanagawa 232-0024 (Japan); Hao, Yoshiteru; Doba, Nobutaka; Hara, Koji [Gastroenterological Center, Yokohama City University Medical Center, 4-57 Urafune-cho, Minami-ku, Yokohama, Kanagawa 232-0024 (Japan); Kondo, Masaaki [Division of Gastroenterology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004 (Japan); Tanaka, Katsuaki [Gastroenterological Center, Yokohama City University Medical Center, 4-57 Urafune-cho, Minami-ku, Yokohama, Kanagawa 232-0024 (Japan); Maeda, Shin [Division of Gastroenterology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004 (Japan)

    2017-04-15

    Purpose: The purpose of this study was to evaluate whether the hypervascularity of hepatocellular carcinomas (HCCs) on contrast-enhanced ultrasonography (CEUS) prior to radiofrequency ablation (RFA) is a significant risk factor for local recurrence after RFA. Materials and methods: Institutional review board approval and informed consent were obtained. Overall, 208 patients (mean age, 71.7 years; range, 50–87 years; 137 men, 71 women) with 282 HCCs treated with RFA were analyzed retrospectively. The mean maximum tumor diameter was 15.7 mm. We compared the abilities of CEUS and contrast-enhanced computed tomography (CECT) to detect hypervascularity in HCCs. We then classified the HCCs into two groups according to the arterial-phase CEUS findings: a “hypervascular group” with whole or partial hypervascular areas within the lesions compared with the surrounding liver parenchyma, and a “non-hypervascular group” with isovascular or hypovascular areas within the lesions. We assessed the cumulative rate of local recurrence after RFA, and we also evaluated the risk factors for local recurrence using a univariate analysis. Results: The detection rate for hypervascular HCCs was significantly higher using CEUS (78%, 221/282) than that using CECT (66%, 186/282) (P < 0.001). Using the CEUS findings, the cumulative rate of local recurrence was significantly higher in the hypervascular group (41.2%, 56/221) than in the non-hypervascular group (18.4%, 6/61) (P = 0.007). A univariate analysis revealed that hypervascularity on CEUS was an independent risk factor for local recurrence (P = 0.010). Conclusion: Hypervascularity in HCCs as observed using CEUS is a significant risk factor for local recurrence after RFA.

  3. Early prediction of tumor recurrence based on CT texture changes after stereotactic ablative radiotherapy (SABR) for lung cancer

    International Nuclear Information System (INIS)

    Mattonen, Sarah A.; Palma, David A.; Haasbeek, Cornelis J. A.; Senan, Suresh; Ward, Aaron D.

    2014-01-01

    Purpose: Benign computed tomography (CT) changes due to radiation induced lung injury (RILI) are common following stereotactic ablative radiotherapy (SABR) and can be difficult to differentiate from tumor recurrence. The authors measured the ability of CT image texture analysis, compared to more traditional measures of response, to predict eventual cancer recurrence based on CT images acquired within 5 months of treatment. Methods: A total of 24 lesions from 22 patients treated with SABR were selected for this study: 13 with moderate to severe benign RILI, and 11 with recurrence. Three-dimensional (3D) consolidative and ground-glass opacity (GGO) changes were manually delineated on all follow-up CT scans. Two size measures of the consolidation regions (longest axial diameter and 3D volume) and nine appearance features of the GGO were calculated: 2 first-order features [mean density and standard deviation of density (first-order texture)], and 7 second-order texture features [energy, entropy, correlation, inverse difference moment (IDM), inertia, cluster shade, and cluster prominence]. For comparison, the corresponding response evaluation criteria in solid tumors measures were also taken for the consolidation regions. Prediction accuracy was determined using the area under the receiver operating characteristic curve (AUC) and two-fold cross validation (CV). Results: For this analysis, 46 diagnostic CT scans scheduled for approximately 3 and 6 months post-treatment were binned based on their recorded scan dates into 2–5 month and 5–8 month follow-up time ranges. At 2–5 months post-treatment, first-order texture, energy, and entropy provided AUCs of 0.79–0.81 using a linear classifier. On two-fold CV, first-order texture yielded 73% accuracy versus 76%–77% with the second-order features. The size measures of the consolidative region, longest axial diameter and 3D volume, gave two-fold CV accuracies of 60% and 57%, and AUCs of 0.72 and 0.65, respectively

  4. In vitro thermal profile suitability assessment of acids and bases for thermochemical ablation: underlying principles.

    Science.gov (United States)

    Freeman, Laura A; Anwer, Bilal; Brady, Ryan P; Smith, Benjamin C; Edelman, Theresa L; Misselt, Andrew J; Cressman, Erik N K

    2010-03-01

    To measure and compare temperature changes in a recently developed gel phantom for thermochemical ablation as a function of reagent strength and concentration with several acids and bases. Aliquots (0.5-1 mL) of hydrochloric acid or acetic acid and sodium hydroxide or aqueous ammonia were injected for 5 seconds into a hydrophobic gel phantom. Stepwise increments in concentration were used to survey the temperature changes caused by these reactions. Injections were performed in triplicate, measured with a thermocouple probe, and plotted as functions of concentration and time. Maximum temperatures were reached almost immediately in all cases, reaching 75 degrees C-110 degrees C at the higher concentrations. The highest temperatures were seen with hydrochloric acid and either base. More concentrated solutions of sodium hydroxide tended to mix incompletely, such that experiments at 9 M and higher were difficult to perform consistently. Higher concentrations for any reagent resulted in higher temperatures. Stronger acid and base combinations resulted in higher temperatures versus weak acid and base combinations at the same concentration. Maximum temperatures obtained are in a range known to cause tissue coagulation, and all combinations tested therefore appeared suitable for further investigation in thermochemical ablation. Because of the loss of the reaction chamber shape at higher concentrations of stronger agents, the phantom does not allow complete characterization under these circumstances. Adequate mixing of reagents to maximize heating potential and avoid systemic exposure to unreacted acid and base must be addressed if the method is to be safely employed in tissues. In addition, understanding factors that control lesion shape in a more realistic tissue model will be critical. Copyright 2010 SIR. Published by Elsevier Inc. All rights reserved.

  5. Computational modelling of internally cooled wet (ICW) electrodes for radiofrequency ablation: impact of rehydration, thermal convection and electrical conductivity.

    Science.gov (United States)

    Trujillo, Macarena; Bon, Jose; Berjano, Enrique

    2017-09-01

    (1) To analyse rehydration, thermal convection and increased electrical conductivity as the three phenomena which distinguish the performance of internally cooled electrodes (IC) and internally cooled wet (ICW) electrodes during radiofrequency ablation (RFA), (2) Implement a RFA computer model with an ICW which includes these phenomena and (3) Assess their relative influence on the thermal and electrical tissue response and on the coagulation zone size. A 12-min RFA in liver was modelled using an ICW electrode (17 G, 3 cm tip) by an impedance-control pulsing protocol with a constant current of 1.5 A. A model of an IC electrode was used to compare the ICW electrode performance and the computational results with the experimental results. Rehydration and increased electrical conductivity were responsible for an increase in coagulation zone size and a delay (or absence) in the occurrence of abrupt increases in electrical impedance (roll-off). While the increased electrical conductivity had a remarkable effect on enlarging the coagulation zone (an increase of 0.74 cm for differences in electrical conductivity of 0.31 S/m), rehydration considerably affected the delay in roll-off, which, in fact, was absent with a sufficiently high rehydration level. In contrast, thermal convection had an insignificant effect for the flow rates considered (0.05 and 1 mL/min). Computer results suggest that rehydration and increased electrical conductivity were mainly responsible for the absence of roll-off and increased size of the coagulation zone, respectively, and in combination allow the thermal and electrical performance of ICW electrodes to be modelled during RFA.

  6. Tumoral response factors after radiofrequency ablation of hepatocellular carcinoma in cirrhotic liver Factores de respuesta tumoral tras ablación mediante radiofrecuencia del carcinoma hepatocelular sobre cirrosis

    Directory of Open Access Journals (Sweden)

    J. Calleja Kempin

    2005-10-01

    Full Text Available Objective: hepatocellular carcinoma (HCC ablation by radiofrequency (RFA is a novel technique with a great variety of methods whose efficacy and predictive factors have not been completely studied. Some of the main predictive factors in this type of treatment are analyzed in the present study. Patients and methods: ninety-three patients with hepatocellular carcinoma over cirrhosis, and with no indication for surgical resection were treated by RFA. Two different types of electrodes were used for RFA (refrigerated-"Cool-Tip" and perfusion with saline solution, the approach was percutaneous, by laparoscopy or laparotomy. Results: overall survival at 1, 2 and 3 years was 88, 81, and 76%, with a free-disease survival (FDS of 66, 31 and 17%, respectively. For tumors less than 3 cm, FDS at 1,2 and 3 years was 74, 44 and 30%, while for more than 3 cm in size FDS was 55, 12 and 0% (p = 0.02. FDS for HCC with one nodule was 70, 36 and 22%, and for more than one nodule it decreased to 50, 17 and 0% at 1, 2 and 3 years, respectively (p = 0.07. Surprisingly, the method employed for RFA has a main influence in FDS, with 0% at 3 years for perfusion electrodes and 26% for cool-tip electrodes at the same period. Conclusions: in this series, overall survival at three years was relatively high; however, tumoral size, number of nodules and RFS method were independent variables associated with disease-free survival.Objetivo: la ablación por radiofrecuencia del hepatocarcinoma (ARF es una técnica de reciente adquisición, cuya eficacia y factores predictivos no han sido suficientemente evaluados. El presente estudio fue diseñado para este análisis. Pacientes y métodos: se han tratado 93 pacientes con hepatocarcinoma sobre hígado cirrótico sin criterios de resección ni de trasplante hepático. El tratamiento se realizó mediante abordaje percutáneo, laparoscópico o mediante laparotomía con dos tipos de electrodos de radiofrecuencia, electrodo refrigerado y

  7. Prognostic factors for long-term outcome after percutaneous thermal ablation for hepatocellular carcinoma: a survival analysis of 137 consecutive patients

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H.-X. [Department of Medical Ultrasonics, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou (China); Lu, M.-D. [Department of Hepatobiliary Surgery, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou (China); Xie, X.-Y. [Department of Medical Ultrasonics, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou (China); Yin, X.-Y. [Department of Hepatobiliary Surgery, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou (China); Kuang, M. [Department of Hepatobiliary Surgery, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou (China); Chen, J.-W. [Department of Hepatobiliary Surgery, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou (China); Xu, Z.-F. [Department of Medical Ultrasonics, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou (China); Liu, G.-J. [Department of Medical Ultrasonics, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou (China)

    2005-09-01

    AIM: To identify prognostic factors for long-term outcome for patients with hepatocellular carcinoma (HCC) after percutaneous microwave or radiofrequency ablation. MATERIALS AND METHODS: In total, 137 consecutive patients with HCC underwent microwave or radiofrequency ablation with curative intent; 16 possible prognostic factors were evaluated for their association with overall survival (OS) and disease-free survival (DFS) using univariate and multivariate analysis. RESULTS: The median OS and DFS were 27.0 months and 8.2 months, respectively. OS rates for all patients at 1, 2, 3, 4 and 5 years were 73.9%, 52.1%, 42.8%, 26.2% and 20.1%, respectively. DFS rates at 1, 2, 3 and 4 years were 38.1%, 21.9%, 18.8%, and 14.1%, respectively. Pretreatment serum alpha-fetoprotein (AFP) >200 ng/ml, pretreatment serum albumin {<=}35 g/dl, liver function Child's class C and incomplete ablation were found to be significant predictors for OS by univariate analysis. Using multivariate analysis, incomplete ablation was identified to be the most significant independent predictor for OS. Other independent predictors for OS were serum albumin level, serum AFP level and Child-Pugh classification. Recurrence after hepatectomy and prothrombin time >14 s were identified to be significant predictors for DFS by univariate analysis, and the former was the only independent predictor for DFS by multivariate analysis. CONCLUSION: Prognosis for patients with HCC after thermal ablation with curative intent was determined by treatment response to ablation, pretreatment serum AFP, and liver function reserve. Tumour response to treatment was the most predictive factor for long-term survival and was related to tumour size, thus careful selection of patients for ablation therapy is recommended.

  8. Prognostic factors for long-term outcome after percutaneous thermal ablation for hepatocellular carcinoma: a survival analysis of 137 consecutive patients

    International Nuclear Information System (INIS)

    Xu, H.-X.; Lu, M.-D.; Xie, X.-Y.; Yin, X.-Y.; Kuang, M.; Chen, J.-W.; Xu, Z.-F.; Liu, G.-J.

    2005-01-01

    AIM: To identify prognostic factors for long-term outcome for patients with hepatocellular carcinoma (HCC) after percutaneous microwave or radiofrequency ablation. MATERIALS AND METHODS: In total, 137 consecutive patients with HCC underwent microwave or radiofrequency ablation with curative intent; 16 possible prognostic factors were evaluated for their association with overall survival (OS) and disease-free survival (DFS) using univariate and multivariate analysis. RESULTS: The median OS and DFS were 27.0 months and 8.2 months, respectively. OS rates for all patients at 1, 2, 3, 4 and 5 years were 73.9%, 52.1%, 42.8%, 26.2% and 20.1%, respectively. DFS rates at 1, 2, 3 and 4 years were 38.1%, 21.9%, 18.8%, and 14.1%, respectively. Pretreatment serum alpha-fetoprotein (AFP) >200 ng/ml, pretreatment serum albumin ≤35 g/dl, liver function Child's class C and incomplete ablation were found to be significant predictors for OS by univariate analysis. Using multivariate analysis, incomplete ablation was identified to be the most significant independent predictor for OS. Other independent predictors for OS were serum albumin level, serum AFP level and Child-Pugh classification. Recurrence after hepatectomy and prothrombin time >14 s were identified to be significant predictors for DFS by univariate analysis, and the former was the only independent predictor for DFS by multivariate analysis. CONCLUSION: Prognosis for patients with HCC after thermal ablation with curative intent was determined by treatment response to ablation, pretreatment serum AFP, and liver function reserve. Tumour response to treatment was the most predictive factor for long-term survival and was related to tumour size, thus careful selection of patients for ablation therapy is recommended

  9. Radiofrequency Ablation Treatment for Renal Cell Carcinoma: Early Clinical Experience

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seong Hoon; Yoon, Seong Kuk; Cho, Jin Han; Oh, Jong Young; Nam, Kyung Jin; Kwon, Hee Jin; Kim, Su Yeon; Kang, Myong Jin; Choi, Sun Seob; Sung, Gyung Tak [Dong-A University College of Medicine, Busan (Korea, Republic of)

    2008-08-15

    To evaluate the early clinical experience associated with radiofrequency (RF) ablation in patients with renal cell carcinoma (RCC). The RF ablation treatment was performed on 17 tumors from 16 patients (mean age, 60.5 years; range, 43 73 years) with RCC. The treatment indications were localized, solid renal mass, comorbidities, high operation risk, and refusal to perform surgery. All tumors were treated by a percutaneous CT (n = 10), followed by an US-guided (n = 2), laparoscopy-assisted US (n = 2), and an open (n = 2) RF ablation. Furthermore, patients underwent a follow- up CT at one day, one week, one month, three and six months, and then every six months from the onset of treatment. We evaluated the technical success, technical effectiveness, ablation zone, benign periablation enhancement, irregular peripheral enhancement, and complications. All 17 exophytic tumors (mean size, 2.2 cm; range, 1.1 5.0 cm) were completely ablated. Technical success and effectiveness was achieved in all cases and the mean follow-up period was 23.8 months (range, 17 33 months). A local recurrence was not detected in any of the cases; however, five patients developed complications as a result of treatment, including hematuria (n = 2), mild thermal injury of the psoas muscle (n = 1), mild hydronephrosis (n = 1), and fistula formation (n = 1). The RF ablation is an alternative treatment for exophytic RCCs and represents a promising treatment for some patients with small RCCs.

  10. Radiofrequency Ablation Treatment for Renal Cell Carcinoma: Early Clinical Experience

    International Nuclear Information System (INIS)

    Park, Seong Hoon; Yoon, Seong Kuk; Cho, Jin Han; Oh, Jong Young; Nam, Kyung Jin; Kwon, Hee Jin; Kim, Su Yeon; Kang, Myong Jin; Choi, Sun Seob; Sung, Gyung Tak

    2008-01-01

    To evaluate the early clinical experience associated with radiofrequency (RF) ablation in patients with renal cell carcinoma (RCC). The RF ablation treatment was performed on 17 tumors from 16 patients (mean age, 60.5 years; range, 43 73 years) with RCC. The treatment indications were localized, solid renal mass, comorbidities, high operation risk, and refusal to perform surgery. All tumors were treated by a percutaneous CT (n = 10), followed by an US-guided (n = 2), laparoscopy-assisted US (n = 2), and an open (n = 2) RF ablation. Furthermore, patients underwent a follow- up CT at one day, one week, one month, three and six months, and then every six months from the onset of treatment. We evaluated the technical success, technical effectiveness, ablation zone, benign periablation enhancement, irregular peripheral enhancement, and complications. All 17 exophytic tumors (mean size, 2.2 cm; range, 1.1 5.0 cm) were completely ablated. Technical success and effectiveness was achieved in all cases and the mean follow-up period was 23.8 months (range, 17 33 months). A local recurrence was not detected in any of the cases; however, five patients developed complications as a result of treatment, including hematuria (n = 2), mild thermal injury of the psoas muscle (n = 1), mild hydronephrosis (n = 1), and fistula formation (n = 1). The RF ablation is an alternative treatment for exophytic RCCs and represents a promising treatment for some patients with small RCCs

  11. Measurement of Pleural Temperature During Radiofrequency Ablation of Lung Tumors to Investigate Its Relationship to Occurrence of Pneumothorax or Pleural Effusion

    International Nuclear Information System (INIS)

    Tajiri, Nobuhisa; Hiraki, Takao; Mimura, Hidefumi; Gobara, Hideo; Mukai, Takashi; Hase, Soichiro; Fujiwara, Hiroyasu; Iguchi, Toshihiro; Sakurai, Jun; Aoe, Motoi; Sano, Yoshifumi; Date, Hiroshi; Kanazawa, Susumu

    2008-01-01

    The purpose of this study was to investigate the relationship between pleural temperature and pneumothorax or pleural effusion after radiofrequency (RF) ablation of lung tumors. The pleural temperature was measured immediately outside the lung surface nearest to the tumor with a fiber-type thermocouple during 25 ablation procedures for 34 tumors in 22 patients. The procedures were divided into two groups depending on the highest pleural temperature: P-group I and P-group II, with highest pleural temperatures of <40 deg. C and ≥40 deg. C, respectively. The incidence of pneumothorax or pleural effusion was compared between the groups. Multiple variables were compared between the groups to determine the factors that affect the pleural temperature. The overall incidence of pneumothorax and pleural effusion was 56% (14/25) and 20% (5/25), respectively. Temperature data in five ablation procedures were excluded from the analyses because these were affected by the pneumothorax. P-group I and P-group II comprised 10 procedures and 10 procedures, respectively. The incidence of pleural effusion was significantly higher in P-group II (4/10) than in P-group I (0/10) (p = 0.043). However, the incidence of pneumothorax did not differ significantly (p = 0.50) between P-group I (4/10) and P-group II (5/10). Factors significantly affecting the pleural temperature were distance between the electrode and the pleura (p < 0.001) and length of the lung parenchyma between the electrode and the pleura (p < 0.001). We conclude that higher pleural temperature appeared to be associated with the occurrence of pleural effusion and not with that of pneumothorax

  12. Thermal effects induced by laser ablation in non-homogeneous limestone covered by an impurity layer

    Science.gov (United States)

    Cocean, Alexandru; Pelin, Vasile; Cazacu, Marius Mihai; Cocean, Iuliana; Sandu, Ion; Gurlui, Silviu; Iacomi, Felicia

    2017-12-01

    This paper reports preliminary results concerning thermal effects induced by urban/industrial air pollutants deposited on a limestone rock when heated by pulsed laser in the cleaning process. The process of laser cleaning treatment of the crust is simulated using COMSOL Multiphysics 4.4, finite element analysis software. Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy and Laser Induced Breakdown Spectroscopy techniques have been used to analyze the chemical composition of the samples. Two elements found as being present into the dust and in the crust, such as iron and magnesium particles are used for simulation in COMSOL. Therefore, the profiles heat evolutions on the crust surface and inside limestone are obtained as thermal interactions between the three components (iron, magnesium and limestone), simulating the non-homogeneous materials. It has been observed that iron impurities caused by the dust deposition may damage the limestone through a process of overheating, as a consequence of a high thermal conduction phenomenon, recorded for the region with iron impurities and sizes of micrometric order are localized. The thermal contact between the three components results in plots that reflect their thermal interactions.

  13. Influence of wavelength and pulse duration on peripheral thermal and mechanical damage to dentin and alveolar bone during IR laser ablation

    Science.gov (United States)

    Lee, C.; Ragadio, Jerome N.; Fried, Daniel

    2000-03-01

    The objective of this study was to measure the peripheral thermal damage produced during the laser ablation of alveolar bone and dentin for clinically relevant IR laser systems. Previous studies have demonstrated that a char layer produced around the laser incision site can inhibit the wound healing process. Moreover, in the case of dentin, a char layer is unsightly and is difficult to bond to with restorative materials. Thermal damage was assessed using polarized light microscopy for laser pulse widths from 500 ns to 300 microseconds at 2.94 micrometer and 9.6 micrometer. Water- cooling was not employed to alleviate thermal damage during the laser irradiation. At 9.6 micrometer, minimal thermal damage was observed for pulse widths on the order of the thermal relaxation time of the deposited laser energy in the tissue, 3 - 4 microseconds, and peripheral thermal damage increased with increasing pulse duration. At 2.94 micrometer, thermal damage was minimal for the Q-switched (500 ns) laser system. This study shows that 9.6 micrometer CO2 laser pulses with pulse widths of 5 - 10 microseconds are well suited for the efficient ablation of dentin and bone with minimal peripheral damage. This work was supported by NIH/NIDCR R29DE12091.

  14. Genetic ablation of Bcl-x attenuates invasiveness without affecting apoptosis or tumor growth in a mouse model of pancreatic neuroendocrine cancer.

    Directory of Open Access Journals (Sweden)

    Jeffrey H Hager

    Full Text Available Tumor cell death is modulated by an intrinsic cell death pathway controlled by the pro- and anti-apoptotic members of the Bcl-2 family. Up-regulation of anti-apoptotic Bcl-2 family members has been shown to suppress cell death in pre-clinical models of human cancer and is implicated in human tumor progression. Previous gain-of-function studies in the RIP1-Tag2 model of pancreatic islet carcinogenesis, involving uniform or focal/temporal over-expression of Bcl-x(L, demonstrated accelerated tumor formation and growth. To specifically assess the role of endogenous Bcl-x in regulating apoptosis and tumor progression in this model, we engineered a pancreatic beta-cell-specific knockout of both alleles of Bcl-x using the Cre-LoxP system of homologous recombination. Surprisingly, there was no appreciable effect on tumor cell apoptosis rates or on tumor growth in the Bcl-x knockout mice. Other anti-apoptotic Bcl-2 family members were expressed but not substantively altered at the mRNA level in the Bcl-x-null tumors, suggestive of redundancy without compensatory transcriptional up-regulation. Interestingly, the incidence of invasive carcinomas was reduced, and tumor cells lacking Bcl-x were impaired in invasion in a two-chamber trans-well assay under conditions mimicking hypoxia. Thus, while the function of Bcl-x in suppressing apoptosis and thereby promoting tumor growth is evidently redundant, genetic ablation implicates Bcl-x in selectively facilitating invasion, consistent with a recent report documenting a pro-invasive capability of Bcl-x(L upon exogenous over-expression.

  15. High-speed scanning ablation of dental hard tissues with a λ=9.3-μm CO2 laser: heat accumulation and peripheral thermal damage

    Science.gov (United States)

    Nguyen, Daniel; Staninec, Michal; Lee, Chulsung; Fried, Daniel

    2010-02-01

    A mechanically scanned CO2 laser operated at high laser pulse repetition rates can be used to rapidly and precisely remove dental decay. This study aims to determine whether these laser systems can safely ablate enamel and dentin without excessive heat accumulation and peripheral thermal damage. Peripheral thermal damage can adversely impact the mechanical strength of the irradiated tissue, particularly for dentin, and reduce the adhesion characteristics of the modified surfaces. Samples were derived from noncarious extracted molars. Pulpal temperatures were recorded using microthermocouples situated at the pulp chamber roof of samples (n=12), which were occlusally ablated using a rapid-scanning, water-cooled 300 Hz CO2 laser over a two minute time course. The mechanical strength of facially ablated dentin (n=10) was determined via four-point bend test and compared to control samples (n=10) prepared with 320 grit wet sand paper to simulate conventional preparations. Composite-to-enamel bond strength was measured via single-plane shear test for ablated/non-etched (n=10) and ablated/acid-etched (n=8) samples and compared to control samples (n=9) prepared by 320 grit wet sanding. Thermocouple measurements indicated that the temperature remained below ambient temperature at 19.0°C (s.d.=0.9) if water-cooling was used. There was no discoloration of either dentin and enamel, the treated surfaces were uniformly ablated and there were no cracks observable on the laser treated surfaces. Fourpoint bend tests yielded mean mechanical strengths of 18.2 N (s.d.=4.6) for ablated dentin and 18.1 N (s.d.=2.7) for control (p>0.05). Shear tests yielded mean bond strengths of 31.2 MPa (s.d.=2.5, penamel without excessive heat accumulation and with minimal thermal damage. It is not clear whether the small (16%) but statistically significant reduction in the shear bond strength to enamel is clinically significant since the mean shear bond strength exceeded 30 MPa.

  16. Effect of mechanical tissue properties on thermal damage in skin after IR-laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Frenz, M.; Romano, V.; Forrer, M.; Weber, H.P. (Inst. of Applied Physics, Bern Univ. (Switzerland)); Mischler, C.; Mueller, O.M. (Anatomical Inst., Bern Univ. (Switzerland))

    1991-04-01

    The damage created instantaneously in dorsal skin and in the subjacent skeletal muscle layer after CO{sub 2} and Er{sup 3+} laser incisions is histologically and ultrastructurally investigated. Light microscopical examinations show an up to three times larger damage zone in the subcutaneous layer of skeletal muscle than in the connective tissue above. The extent of thermally altered muscle tissue is classified by different zones and characterized by comparison to long time heating injuries. The unexpectedly large damage is a result of the change of elastic properties occurring abruptly at the transition between different materials. This leads to a discontinuity of the cutting dynamics that reduces the ejection of tissue material. We show that the degree of thermal damage originates from the amount of hot material that is not ejected out of the crater acting as a secondary heat source. (orig.).

  17. Pre-treatment double- or triple-positive tumor markers are predictive of a poor outcome for patients undergoing radiofrequency ablation for hepatocellular carcinoma.

    Science.gov (United States)

    Nitta, Hidetoshi; Nakagawa, Shigeki; Kaida, Takayoshi; Arima, Kota; Higashi, Takaaki; Taki, Katsunobu; Okabe, Hirohisa; Hayashi, Hiromitsu; Hashimoto, Daisuke; Chikamoto, Akira; Ishiko, Takatoshi; Beppu, Toru; Baba, Hideo

    2017-03-01

    We evaluated the therapeutic effect of radiofrequency ablation (RFA) on hepatocellular carcinoma (HCC) according to the number of positive tumor markers. The subjects of this study were 160 patients who underwent percutaneous and surgical RFA for HCC. Patients were divided into negative (n = 51), single- (n = 69), double- (n = 31), and triple-positive (n = 9) tumor marker groups according to the pre-treatment expression of these markers. We looked for any relationships among clinical parameters, outcomes, and tumor markers. The 3-year recurrence-free and overall survival rates of the negative, single-, double-, and triple-positive groups were 30, 19, 16, and 11 % (P = 0.02), and 94, 88, 67, and 37 % (P tumor marker profile was independently associated with local recurrence [hazard ratio (HR) 5.48, 95 % confidence interval (CI) 2.44-12.33, P tumor markers.

  18. The early supra-additive apoptotic response of R3327-G prostate tumors to androgen ablation and radiation is not sustained with multiple fractions

    International Nuclear Information System (INIS)

    Pollack, Alan; Ashoori, Faramarz; Sikes, Charles; Lim Joon, Daryl; Eschenbach, Andrew C. von; Zagars, Gunar K.; Meistrich, Marvin L.

    2000-01-01

    Purpose: The treatment of R3327-G tumor-bearing rats with androgen ablation (AA) via castration results in a supra-additive increase in apoptosis when 2-8 Gy γ-irradiation (RT) is given as a single dose 3-14 days afterwards. We report here the dose response and effect of multiple fractions on this supra-additive apoptotic response. Materials and Methods: Dunning R3327-G tumors were grown in the flanks of Copenhagen rats and the experiments were initiated at a tumor volume of 1.0-1.5 cc. Androgen ablation was achieved by castration 3 days prior to γ-irradiation. Apoptosis was measured with a terminal deoxynucleotidyl transferase dUTP-biotin nick end-labeling assay 6-h after RT, unless otherwise specified. Results: The dose response of the supra-additive apoptotic response was assessed by irradiating castrated animals with single doses of 2, 4, 8, or 16 Gy (n = 5 per group); tumor cell apoptosis at 6-h following irradiation was 2.4% ± 0.7% (± SEM), 4.2% ± 0.8%, 6.5% ± 1.4%, and 1.6% ± 0.3%, respectively. The RT only and AA only controls had < 1% apoptosis. The effect of fractionated RT on apoptosis was investigated to determine if the supra-additive apoptotic response was sustained with repeated 2-8 Gy fractions. When tumor-bearing animals were treated with repeated daily 2-Gy fractions, there was a reduction in the level of the supra-additive apoptotic response. After five 2-Gy fractions at 24-h intervals, apoptosis in the combined treated tumors was at levels seen in the AA controls. This raised the possibility that more than 24 h are required for recovery of the high supra-additive apoptotic levels seen after one fraction. When the interfraction interval was extended to 96 h, there was no significant increase in apoptosis over the additive effect of AA and RT. Although there was a decline in supra-additive apoptosis with repeated fractions, a dose response for tumor growth delay was evident for RT alone using 2.5-Gy fractions. Moreover, the combination of

  19. Radiofrequency Thermal Ablation versus Bipolar Electrocautery for the Treatment of Inferior Turbinate Hypertrophy: Comparison of Efficacy and Postoperative Morbidity

    Directory of Open Access Journals (Sweden)

    Uluyol, Sinan

    2015-04-01

    Full Text Available Introduction Numerous surgical methods are used to treat nasal obstruction due to inferior turbinate hypertrophy. The primary goal of the therapy is to maximize the nasal airway for as extended a period of time as possible while minimizing therapeutic complications. Objectives The aim of this study was to assess the effects of radiofrequency thermal ablation (RFTA and bipolar electrocautery (BEC on the removal of nasal obstruction in patients with inferior turbinate hypertrophy and on nasal mucociliary clearance (MCC. Patients in both groups were also evaluated in terms of postoperative morbidity. Methods We compared the outcomes of two groups of patients: those treated with RFTA (n = 23 and those who underwent BEC (n = 20. Nasal obstruction was graded using a visual analog scale (VAS and MCC was measured using a saccharin clearance test. Both measurements were performed before and 2 months after treatment. Results Pre- and postoperative VAS scores showed significant improvement for both groups. However, MCC results did not significantly differ between two groups. Neither edema nor crust formation persisted for more than 1 week in any patients. Conclusion Submucosal cauterization with preservation of the nasal mucosa and periosteum is as effective and safe as RFTA and should be considered when planning inferior turbinate interventions.

  20. Transarterial embolization (TAE) as add-on to percutaneous radiofrequency ablation (RFA) for the treatment of renal tumors: Review of the literature, overview of state-of-the-art embolization materials and further perspective of advanced image-guided tumor ablation

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, C.M., E-mail: christof.sommer@med.uni-heidelberg.de [Clinic for Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg (Germany); Clinic for Diagnostic and Interventional Radiology, Klinikum Stuttgart, Katharinenhospital, Stuttgart (Germany); Pallwein-Prettner, L., E-mail: leo.pallwein-prettner@bhs.at [Department of Diagnostic and Interventional Radiology, Krankenhaus der Barmherzigen Schwestern Linz, Linz (Austria); Vollherbst, D.F., E-mail: dominik@vollherbst.de [Clinic for Radiology, Minimally-Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Heilbronn (Germany); Seidel, R., E-mail: roland.seidel@uks.eu [Clinic for Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg/Saar (Germany); Rieder, C., E-mail: christian.rieder@mevis.fraunhofer.de [Fraunhofer MEVIS, Institute for Medical Image Computing, Bremen (Germany); Radeleff, B.A., E-mail: boris.radeleff@med.uni-heidelberg.de [Clinic for Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg (Germany); Kauczor, H.U., E-mail: hu.kauczor@med.uni-heidelberg.de [Clinic for Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg (Germany); Wacker, F., E-mail: wacker.frank@mh-hannover.de [Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover (Germany); Richter, G.M., E-mail: g.richter@klinikum-stuttgart.de [Clinic for Diagnostic and Interventional Radiology, Klinikum Stuttgart, Katharinenhospital, Stuttgart (Germany); Bücker, A., E-mail: arno.buecker@uks.eu [Clinic for Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg/Saar (Germany); Rodt, T., E-mail: rodt.thomas@mh-hannover.de [Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover (Germany); and others

    2017-01-15

    Highlights: • TAE as add-on to percutaneous RFA is feasible, safe, and very effective. • State-of-the-art embolization materials include tightly-size-calibrated microspheres. • MWA, cryoablation and IRE are TA systems beyond RFA. • Visible beads rank among the most promising innovative embolization materials. • Software-based solutions will be increasingly important for treatment guidance. - Abstract: Percutaneous radiofrequency ablation (RFA) for the treatment of stage I renal cell carcinoma has recently gained significant attention as the now available long-term and controlled data demonstrate that RFA can result in disease-free and cancer-specific survival comparable with partial and/or radical nephrectomy. In the non-controlled single center trials, however, the rates of treatment failure vary. Operator experience and ablation technique may explain some of the different outcomes. In the controlled trials, a major limitation is the lack of adequate randomization. In case reports, original series and overview articles, transarterial embolization (TAE) before percutaneous RFA was promising to increase tumor control and to reduce complications. The purpose of this study was to systematically review the literature on TAE as add-on to percutaneous RFA for renal tumors. Specific data regarding technique, tumor and patient characteristics as well as technical, clinical and oncologic outcomes have been analyzed. Additionally, an overview of state-of-the-art embolization materials and the radiological perspective of advanced image-guided tumor ablation (TA) will be discussed. In conclusion, TAE as add-on to percutaneous RFA is feasible and very effective and safe for the treatment of T1a tumors in difficult locations and T1b tumors. Advanced radiological techniques and technologies such as microwave ablation, innovative embolization materials and software-based solutions are now available, or will be available in the near future, to reduce the limitations of

  1. Comparative study of nanosecond electric fields in vitro and in vivo on hepatocellular carcinoma indicate macrophage infiltration contribute to tumor ablation in vivo.

    Directory of Open Access Journals (Sweden)

    Xinhua Chen

    Full Text Available BACKGROUND AND AIM: Recurrence and metastasis are associated with poor prognosis in hepatocellular carcinoma even in the patients who have undergone radical resection. Therefore, effective treatment is urgently needed for improvement of patients' survival. Previously, we reported that nanosecond pulse electric fields (nsPEFs can ablate melanoma by induction of apoptosis and inhibition of angiogenesis. This study aims to investigate the in vivo ablation strategy by comparing the dose effect of nanosecond electric fields in vitro and in vivo on hepatocellular carcinoma. MATERIALS AND METHODS: Four hepatocellular carcinoma cell lines HepG2, SMMC7721, Hep1-6, and HCCLM3 were pulsed to test the anti-proliferation and anti-migration ability of 100 ns nsPEFs in vitro. The animal model of human subdermal xenograft HCCLM3 cells into BALB/c nude mouse was used to test the anti-tumor growth and macrophage infiltration in vivo. RESULTS: In vitro assays showed anti-tumor effect of nsPEFs is dose-dependant. But the in vivo study showed the strategy of low dose and multiple treatments is superior to high dose single treatment. The macrophages infiltration significantly increased in the tumors which were treated by multiple low dose nsPEFs. CONCLUSION: The low dose multiple nsPEFs application is more efficient than high dose single treatment in inhibiting the tumor volume in vivo, which is quite different from the dose-effect relationship in vitro. Beside the electric field strength, the macrophage involvement must be considered to account for effect variability and toxicology in vivo.

  2. Mandibular Reconstruction Using Pectoralis Major Myocutaneous Flap and Titanium Plates after Ablative Surgery for Locally Advanced Tumors of the Oral Cavity

    International Nuclear Information System (INIS)

    El-Zohairy, M.A.F.; Mostafa, A.; Amin, A.; Abd El-Fattah, H.; Khalifa, Sh.

    2009-01-01

    The most common indication for mandible resection remains ablative surgery for cancer of the oral cavity and oropharynx. The use of vascularized bone grafts has become state-of-the-art for mandibular reconstruction. However, the high cost of such surgery may not be justified in patients with advanced disease and poor prognosis, or poor performance status. Objective: The purpose of this study was to evaluate outcomes of mandibular reconstruction using titanium plates covered with a pedicled pectoralis major myocutaneous flap after ablative surgery for locally advanced tumors of the oral cavity. Patients and methods: The study involves a total of 33 patients with locally advanced tumors of the oral cavity that were treated over 5 year period (2003-2008) at the National Cancer Institute, Cairo University, Egypt. Mandibular resections were performed for treatment of patients with primary oral cavity tumors invading the mandible followed by mandibular reconstruction using titanium plates covered with a pedicled pectoralis major myocutaneous flap. Results: Of 33 patients, 25 (75.75%) were males and 8 (24.25%) were females. The age ranged from 42 to 70 years (mean 52.3±5.9 years). Tongue cancer was the most common tumor, it affects 17 (51.5%) of the patients, 24 patients received post operative radiation therapy. The flap survival was 100%; partial necrosis of the flap skin was observed in 3 patients. One patient developed wound dehiscence. Oro-cutaneous fistula occurred in 5 patients that closed spontaneously. There were 4 cases of plate failure, one patient experienced plate fracture at 13 months after reconstruction. Three patients developed external plate exposure. All patients achieved good functional and acceptable aesthetic outcome. The overall cause-specific cumulative survival was 72.7% at one year and 56.1% at two years. Conclusions: Titanium plate and pedicled pectoralis major myocutaneous flap is a safe and reliable option for composite mandibular defects

  3. Thermalization of a UV laser ablation plume in a background gas: From a directed to a diffusionlike flow

    DEFF Research Database (Denmark)

    Amoruso, S.; Toftmann, B.; Schou, Jørgen

    2004-01-01

    Combined diagnostic measurements of deposition rates and ion time-of-flight signals have been employed to study the expansion of a laser ablation plume into a background gas. With increasing gas pressure the angular distribution of the collected ablated atoms becomes broader, while the total...

  4. Genetic ablation of soluble tumor necrosis factor with preservation of membrane tumor necrosis factor is associated with neuroprotection after focal cerebral ischemia

    DEFF Research Database (Denmark)

    Madsen, Pernille M; Clausen, Bettina H; Degn, Matilda

    2016-01-01

    Microglia respond to focal cerebral ischemia by increasing their production of the neuromodulatory cytokine tumor necrosis factor, which exists both as membrane-anchored tumor necrosis factor and as cleaved soluble tumor necrosis factor forms. We previously demonstrated that tumor necrosis factor...... reduced infarct volumes at one and five days after stroke. This was associated with improved functional outcome after experimental stroke. No changes were found in the mRNA levels of tumor necrosis factor and tumor necrosis factor-related genes (TNFR1, TNFR2, TACE), pro-inflammatory cytokines (IL-1β, IL-6...... knockout mice display increased lesion volume after focal cerebral ischemia, suggesting that tumor necrosis factor is neuroprotective in experimental stroke. Here, we extend our studies to show that mice with intact membrane-anchored tumor necrosis factor, but no soluble tumor necrosis factor, display...

  5. Radiofrequency Ablation Using a Multiple-Electrode Switching System for Lung Tumors with 2.0-5.0-cm Maximum Diameter: Phase II Clinical Study.

    Science.gov (United States)

    Kodama, Hiroshi; Yamakado, Koichiro; Hasegawa, Takaaki; Fujimori, Masashi; Yamanaka, Takashi; Takaki, Haruyuki; Uraki, Junji; Nakatsuka, Atsuhiro; Sakuma, Hajime

    2015-12-01

    To prospectively evaluate the safety and effectiveness of radiofrequency ablation (RFA) by using a multiple-electrode switching system to treat 2.0-5.0-cm lung tumors. The institutional review board approved this prospective phase II study. Written informed consent was obtained from all patients. Between September 2009 and July 2011, RFA using two or three radiofrequency (RF) electrodes and a multiple-electrode switching system was performed for malignant lung tumors with a maximum tumor diameter of 2.0-5.0 cm in nonsurgical candidates. The primary endpoint was safety, as evaluated using the Common Terminology Criteria for Adverse Events. Patients were observed for at least 1 year. Local tumor progression and overall survival were analyzed with the Kaplan-Meier method. Thirty-three patients (26 men, seven women; mean age, 70.5 years ± 10.0; age range, 46-87 years) with 35 lung tumors with a mean maximum diameter of 3.0 cm ± 0.7 (standard deviation; range, 2.0-4.4 cm) underwent treatment in 35 sessions. No procedure-related death or grade 4 adverse events (AEs) occurred. Grade 3 AEs occurred in four patients (12%), with pleural effusion requiring chest tube placement in two patients, pneumothorax requiring pleural adhesion in one patient, and pulmonary hemorrhage requiring pulmonary artery coil embolization in one patient. Grade 2 AEs were detected in 13 patients (39%). The 1-year local tumor progression and overall survival rates were 12.7% (95% confidence interval [CI]: 1.0, 25.5) and 81.2% (95% CI: 67.6, 94.8). RFA with a multiple-electrode switching system may be a safe therapeutic option with which to treat 2.0-5.0-cm lung cancer tumors.

  6. Multi-parametric study of temperature and thermal damage of tumor exposed to high-frequency nanosecond-pulsed electric fields based on finite element simulation.

    Science.gov (United States)

    Mi, Yan; Rui, Shaoqin; Li, Chengxiang; Yao, Chenguo; Xu, Jin; Bian, Changhao; Tang, Xuefeng

    2017-07-01

    High-frequency nanosecond-pulsed electric fields were recently introduced for tumor or abnormal tissue ablation to solve some problems of conventional electroporation. However, it is necessary to study the thermal effects of high-field-intensity nanosecond pulses inside tissues. The multi-parametric analysis performed here is based on a finite element model of liver tissue with a tumor that has been punctured by a pair of needle electrodes. The pulse voltage used in this study ranges from 1 to 4 kV, the pulse width ranges from 50 to 500 ns, and the repetition frequency is between 100 kHz and 1 MHz. The total pulse length is 100 μs, and the pulse burst repetition frequency is 1 Hz. Blood flow and metabolic heat generation have also been considered. Results indicate that the maximum instantaneous temperature at 100 µs can reach 49 °C, with a maximum instantaneous temperature at 1 s of 40 °C, and will not cause thermal damage during single pulse bursts. By parameter fitting, we can obtain maximum instantaneous temperature at 100 µs and 1 s for any parameter values. However, higher temperatures will be achieved and may cause thermal damage when multiple pulse bursts are applied. These results provide theoretical basis of pulse parameter selection for future experimental researches.

  7. Percutaneous laser ablation of benign and malignant thyroid nodules.

    Science.gov (United States)

    Papini, Enrico; Bizzarri, Giancarlo; Pacella, Claudio M

    2008-10-01

    Percutaneous image-guided procedures, largely based on thermal ablation, are at present under investigation for achieving a nonsurgical targeted cytoreduction in benign and malignant thyroid lesions. In several uncontrolled clinical trials and in two randomized clinical trials, laser ablation has demonstrated a good efficacy and safety for the shrinkage of benign cold thyroid nodules. In hyperfunctioning nodules, laser ablation induced a nearly 50% volume reduction with a variable frequency of normalization of thyroid-stimulating hormone levels. Laser ablation has been tested for the palliative treatment of poorly differentiated thyroid carcinomas, local recurrences or distant metastases. Laser ablation therapy is indicated for the shrinkage of benign cold nodules in patients with local pressure symptoms who are at high surgical risk. The treatment should be performed only by well trained operators and after a careful cytological evaluation. Laser ablation does not seem to be consistently effective in the long-term control of hyperfunctioning thyroid nodules and is not an alternative treatment to 131I therapy. Laser ablation may be considered for the cytoreduction of tumor tissue prior to external radiation therapy or chemotherapy of local or distant recurrences of thyroid malignancy that are not amenable to surgical or radioiodine treatment.

  8. Harmonic motion imaging for focused ultrasound (HMIFU): a fully integrated technique for sonication and monitoring of thermal ablation in tissues

    International Nuclear Information System (INIS)

    Maleke, C; Konofagou, E E

    2008-01-01

    FUS (focused ultrasound), or HIFU (high-intensity-focused ultrasound) therapy, a minimally or non-invasive procedure that uses ultrasound to generate thermal necrosis, has been proven successful in several clinical applications. This paper discusses a method for monitoring thermal treatment at different sonication durations (10 s, 20 s and 30 s) using the amplitude-modulated (AM) harmonic motion imaging for focused ultrasound (HMIFU) technique in bovine liver samples in vitro. The feasibility of HMI for characterizing mechanical tissue properties has previously been demonstrated. Here, a confocal transducer, combining a 4.68 MHz therapy (FUS) and a 7.5 MHz diagnostic (pulse-echo) transducer, was used. The therapy transducer was driven by a low-frequency AM continuous signal at 25 Hz, producing a stable harmonic radiation force oscillating at the modulation frequency. A pulser/receiver was used to drive the pulse-echo transducer at a pulse repetition frequency (PRF) of 5.4 kHz. Radio-frequency (RF) signals were acquired using a standard pulse-echo technique. The temperature near the ablation region was simultaneously monitored. Both RF signals and temperature measurements were obtained before, during and after sonication. The resulting axial tissue displacement was estimated using one-dimensional cross correlation. When temperature at the focal zone was above 48 deg. C during heating, the coagulation necrosis occurred and tissue damage was irreversible. The HMI displacement profiles in relation to the temperature and sonication durations were analyzed. At the beginning of heating, the temperature at the focus increased sharply, while the tissue stiffness decreased resulting in higher HMI displacements. This was confirmed by an increase of 0.8 μm deg. C -1 (r = 0.93, p -1 , r = -0.92, p -1 , prior to and after lesion formation in seven bovine liver samples, respectively. This technique was thus capable of following the protein-denatured lesion formation based on the

  9. Graphics Processing Unit-Accelerated Nonrigid Registration of MR Images to CT Images During CT-Guided Percutaneous Liver Tumor Ablations.

    Science.gov (United States)

    Tokuda, Junichi; Plishker, William; Torabi, Meysam; Olubiyi, Olutayo I; Zaki, George; Tatli, Servet; Silverman, Stuart G; Shekher, Raj; Hata, Nobuhiko

    2015-06-01

    Accuracy and speed are essential for the intraprocedural nonrigid magnetic resonance (MR) to computed tomography (CT) image registration in the assessment of tumor margins during CT-guided liver tumor ablations. Although both accuracy and speed can be improved by limiting the registration to a region of interest (ROI), manual contouring of the ROI prolongs the registration process substantially. To achieve accurate and fast registration without the use of an ROI, we combined a nonrigid registration technique on the basis of volume subdivision with hardware acceleration using a graphics processing unit (GPU). We compared the registration accuracy and processing time of GPU-accelerated volume subdivision-based nonrigid registration technique to the conventional nonrigid B-spline registration technique. Fourteen image data sets of preprocedural MR and intraprocedural CT images for percutaneous CT-guided liver tumor ablations were obtained. Each set of images was registered using the GPU-accelerated volume subdivision technique and the B-spline technique. Manual contouring of ROI was used only for the B-spline technique. Registration accuracies (Dice similarity coefficient [DSC] and 95% Hausdorff distance [HD]) and total processing time including contouring of ROIs and computation were compared using a paired Student t test. Accuracies of the GPU-accelerated registrations and B-spline registrations, respectively, were 88.3 ± 3.7% versus 89.3 ± 4.9% (P = .41) for DSC and 13.1 ± 5.2 versus 11.4 ± 6.3 mm (P = .15) for HD. Total processing time of the GPU-accelerated registration and B-spline registration techniques was 88 ± 14 versus 557 ± 116 seconds (P processing time. The GPU-accelerated volume subdivision technique may enable the implementation of nonrigid registration into routine clinical practice. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

  10. A Dual-Mode Microwave Applicator for Liver Tumor Thermotherapy

    Science.gov (United States)

    Reimann, Carolin; Schüßler, Martin; Jakoby, Rolf; Bazrafshan, Babak; Hübner, Frank; Vogl, Thomas

    2018-03-01

    The concept of a novel dual-mode microwave applicator for diagnosis and thermal ablation treatment of tumorous tissue is presented in this paper. This approach is realized by integrating a planar resonator array to, firstly, detect abnormalities by a relative dielectric analysis, and secondly, perform a highly localized thermal ablation. A further essential advantage is addressed by designing the applicator to be MRI compatible to provide a multimodal imaging procedure. Investigations for an appropriate frequency range lead to the use of much higher operating frequencies between 5 GHz and 10 GHz, providing a significantly lower power consumption for microwave ablation of only 20 W compared to commercial available applicators.

  11. Gold nanorods coupled with upconverting nanophosphors for targeted thermal ablation and imaging of bladder cancer cells (Conference Presentation)

    Science.gov (United States)

    Cho, Suehyun K.; Su, Lih-Jen; Flaig, Thomas W.; Park, Wounjhang

    2016-09-01

    NaYF4:Yb3+,Er3+ upconverting nanophosphors (UCNPs) are robust and stable nanoparticles that absorb near-infrared (NIR) photons and emit green and red visible photons through energy transfer upconversion. This mechanism provides UCNPs several advantages as a bioimaging agent over traditional fluorescence imaging agent in that NIR excitation allows high-contrast imaging without autofluorescence and that they can be used for deep-tissue imaging. However, additional surface modification of UCNPs is necessary for them to be biocompatible. We use an amphiphilic polymer (poly(maleic anhydride-alt-octadecene) (PMAO) and a hetero-functional polyethylene glycol with amine and thiol ends (NH2-PEG-SH)) to make the UCNPs water-soluble. This reaction yields a carboxylic group that allows functionalization with anti-epidermal growth factor receptor (aEGFR), which provides specific binding of UCNPs to EGFR-expressing bladder cancer cells. Additionally, the thiol ends of the PEGylated UCNPs are able to bind with gold nanorods (AuNRs) to create UCNP-AuNR complexes. The localized surface plasmon of the AuNR then allow localized heating of HTB9 bladder cancer cells, enabling in situ cell killing upon detection by UCNP fluorescence. Here, we report a successful synthesis, surface modification and conjugation of aEGFR functionalized UCNP-AuNR complexes and in vitro imaging and thermal ablation studies using them. Synthesis and surface modification of UCNP-AuNR complexes are confirmed by electron microscopy. Then, a combination of brightfield, NIR confocal fluorescence, and darkfield microscopy on the UCNP-AuNR treated bladder cancer cells revealed successful cancer targeting and imaging capabilities of the complex. Finally, cell viability assay showed that NIR irradiation of UCNP-AuNR conjugated cells resulted highly selective cell killing.

  12. Real-time temperature feedback for nanoparticles based tumor thermal treatment (Conference Presentation)

    Science.gov (United States)

    Steinberg, Idan; Tamir, Gil; Gannot, Israel

    2017-02-01

    Systemic hyperthermia therapy exploits the fact that cancer cells are more sensitive to elevated temperatures than healthy tissue. Systemic application of hyperthermia externally usually leads to low efficiency treatment. Recently, our group and others have proposed an antibody conjugated magnetic nanoparticles (MNPs) approach to overcome the limitation of systemic hyperthermia. MNPs can bind specifically to the tumor sites, thus delivering internal highly effective targeted hyperthermia. However, such internal mechanism requires more complicated controls and monitoring. This current work presents a deep tissue temperature monitoring method to control hyperthermia effectiveness and minimize collateral damage to surrounding tissues. A low-frequency narrowband modulation of the RF field used for MNP heating leads to the generation of diffused thermal waves which propagate to the tissue surface and captured by a thermal camera. A Fourier domain, analytical heat transfer model is used for temperature monitoring algorithm. The ill-posed thermal inverse problem is solved efficiently by iterating over the source power until both the amplitude and phase match the recorded thermal image sequence. The narrow bandwidth thermal stimulation enables acquiring deep signals with high SNR. We show that thermal transverse resolution improves as the stimulation frequency increases even slightly above DC, enabling better heat source transverse separation and margin identification in the case of distributed tumors. These results can be used as a part of an overall image and treat system for efficient detection of tumors, manipulation of MNPs and monitoring MNP based hyperthermia.

  13. Radiofrequency ablation of neuroendocrine liver metastases: the Middlesex experience.

    Science.gov (United States)

    Gillams, A; Cassoni, A; Conway, G; Lees, W

    2005-01-01

    Current treatment options for neuroendocrine liver metastases are not widely applicable or not that effective. Image-guided thermal ablation offers the possibility of a minimally invasive, albeit palliative, treatment that decreases tumor volume, preserves most of the normal liver, and can be repeated several times. We report our experience with image-guided thermal ablation in 25 patients with unresectable liver metastases. Since 1990 we have treated 189 tumors at 66 treatment sessions in 25 patients (12 female, 13 male; median age, 56 years; age range, 26--78 years). Thirty treatments were performed with a solid-state laser, and 36 treatments were performed with radiofrequency ablation. All but one treatment was performed percutaneously under image guidance. Sixteen patients had metastases from carcinoid primaries, three from gastrinoma, two from insulinoma, and four from miscellaneous causes. Fourteen of 25 had symptoms from hormone secretion. Imaging follow-up was available in 19 patients at a median of 21 months (range, 4--75 months). There was a complete response in six patients, a partial response in seven, and stable disease in one; hence, tumor load was controlled in 14 of 19 patients (74%). Relief of hormone-related symptoms was achieved in nine of 14 patients (69%). The median survival period from the diagnosis of liver metastases was 53 months. One patient with end-stage cardiac disease died after a carcinoid crisis. There were eight (12%) complications: five local and three distant, four major and four minor. As a minimally invasive, readily repeatable procedure that can be used to ablate small tumors, preferably before patients become severely symptomatic, radiofrequency ablation can provide effective control of liver tumor volume in most patients over many years.

  14. Thermal dosimetry studies of ultrasonically induced hyperthermia in normal dog brain and in experimental brain tumors

    International Nuclear Information System (INIS)

    Britt, R.H.; Pounds, D.W.; Stuart, J.S.; Lyons, B.E.; Saxer, E.L.

    1984-01-01

    In a series of 16 acute experiments on pentobarbital anesthetized dogs, thermal distributions generated by ultrasonic heating using a 1 MHz PZT transducer were compared with intensity distributions mapped in a test tank. Relatively flat distributions from 1 to 3 cm have been mapped in normal dog brain using ''shaped'' intensity distributions generated from ultrasonic emission patterns which are formed by the interaction between compressional, transverse and flexural modes activated within the crystal. In contrast, these same intensity distributions generated marked temperature variations in 3 malignant brain tumors presumably due to variations in tumor blood flow. The results of this study suggest that a practical clinical system for uniform heating of large tumor volumes with varying volumes and geometries is not an achievable goal. The author's laboratory is developing a scanning ultrasonic rapid hyperthermia treatment system which will be able to sequentially heat small volume of tumor tissue either to temperatures which will sterilize tumor or to a more conventional thermal dose. Time-temperature studies of threshold for thermal damage in normal dog brain are currently in progress

  15. Long-term local control with radiofrequency ablation or radiotherapy for second, third, and fourth lung tumors after lobectomy for primary lung cancer

    International Nuclear Information System (INIS)

    Yokouchi, Hideoki; Murata, Kohei; Miyazaki, Masaki; Miyamoto, Takeaki; Minami, Takafumi; Tsuji, Fumio; Mikami, Koji

    2016-01-01

    A 78-year-old woman developed second, third, and fourth lung tumors at intervals of 1-3 years after left upper lobectomy for primary lung cancer. The tumors were controlled with radiofrequency ablation (RFA) or conventional conformal radiotherapy for 9 years postoperatively. For the treatment of second primary lung cancer or lung metastasis after surgical resection of the primary lung cancer, reoperation is not recommended because of the impaired respiratory reserve. Thus, local therapy such as radiotherapy or RFA is applied in some cases. Among these, stereotactic body radiotherapy (SBRT) is a feasible option because of its good local control and safety, which is comparable with surgery. On the other hand, for cases of multiple lesions that are not suitable for radiotherapy or combination therapy, RFA could be an option because of its short-term local control, easiness, safety, and repeatability. After surgery for primary lung cancer, a second lung tumor could be controlled with highly effective and minimally invasive local therapy if it is recognized as a local disease but is medically inoperable. Therefore, long-term postoperative follow-up for primary lung cancer is beneficial. (author)

  16. Needle track seeding after percutaneous microwave ablation of malignant liver tumors under ultrasound guidance: Analysis of 14-year experience with 1462 patients at a single center

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jie, E-mail: yu-jie301@hotmail.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 (China); Liang, Ping, E-mail: liangping301@hotmail.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 (China); Yu, Xiao-ling, E-mail: dyuxl301@yahoo.com.cn [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 (China); Cheng, Zhi-gang, E-mail: qlczg@hotmail.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 (China); Han, Zhi-yu, E-mail: hanzhiyu301@hotmail.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 (China); Dong, Bao-wei, E-mail: dongbw301@yahoo.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 (China)

    2012-10-15

    Objective: To determine the incidence and risk factors associated with needle tract seeding after percutaneous microwave ablation (MWA) of liver cancer under ultrasound guidance. Materials and methods: Over a 14-year period, a total of 1462 patients with 2530 malignant nodules were treated by MWA. The influence of age, sex, Child-pugh classification, tumor size, tumor position, previous biopsy, insertion number and antenna type on the risk of neoplastic seeding was assessed. The survival of seeding patients after the MWA was analyzed. Results: Eleven patients with 12 nodules (0.47% per tumor, 0.75% per patient) were identified with needle tract seeding with an interval time of 6–37 (median 10) months after MWA. The mean size of the seeding nodule was 2.3 ± 0.7 cm (from 1.3 to 3.9 cm). Only previous biopsy was significantly associated with neoplastic seeding (P = 0.02). All the seeding lesions were successfully treated by resection, MWA, radiation or high intensity focus ultrasound. The median survival period of the 11 patients after the MWA was 36.0 months. The cumulative survival rates of the 11 patients after the MWA at 1-, 2-, 3-, 4- and 5-year were 90.9%, 72.7%, 62.3%, 31.2% and 15.6%, respectively. Conclusion: The results showed that the neoplastic seeding was a low risk complication of percutaneous MWA of liver cancer and was considered acceptable in general.

  17. Ultrasound-guided radiofrequency thermal ablation of normal kidney in a rabbit model: correlation with CT and histopathology

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Won; Lee, Jeong Min; Kin, Chong Soo; Lee, Sang Hun [College of Medicine, Chonbuk National Univ., Chonju (Korea, Republic of)

    2002-01-01

    To assess the feasibility and safety of using a cooled-tip electrode to perform percutaneous radiofrequency ablation of kidney tissue in rabbits, and to evaluate the ability of CT to reveal the appearance and extent of tissue necrosis during follow-up after ablation. Using ultrasound guidance, a 17-G cooled-tip electrode was inserted into the right lower portion of the kidney in 26 New Zealand White rabbits. Radiofrequency was applied for 2 mins, and biphasic helical CT scanning was used to assess tissue destruction and the presence or absence of complications immediately after the procedure and at 24 hrs, 2 and 3 days, and 1,2,3,4,5,6 and 7 weeks. The study had three phases: acute (immediately killed : N=10); subacute (killed at 24 hrs (n=3), 2 days (n=3), 3 days (n=1) : N=7); chronic (killed at 1 week (n=4), 2 weeks (n=2), 4 weeks (n=1), 7 weeks (n=1): N=8). After the animals were killed, their kidneys were histopathologically examined and the radiologic and pathologic findings of lesion size and configuration were correlated. In each instance, ultrasound-guided radiofrequency ablations of the lower pole of the kidney were technically successful. Contrast-enhanced biphasic helical CT revealed regions of hypoattenuation devoid of parenchymal enhancement, and these correlated closely with true pathologic lesion size (r=0.884; p>0.05). In subacute and chronic models, CT scanning revealed gradual spontaneous resorption of the ablated lesion and the presence of perilesional calcification. Histopathologically, in the acute phase the ablated lesion showed coagulative necrosis and infiltration of inflammatory cells, and in the chronic phase there was clear cut necrosis of glomeruli, tubules and renal interstitium, with diminishing inflammatory response and peripheral fibrotic tissue formation. Ultrasound-guided renal radiofrequency ablation is technically feasible and safe. In addition, the avascular lesion measured at contrast-enhanced helical CT closely correlated with

  18. Ultrasound-guided radiofrequency thermal ablation of normal kidney in a rabbit model: correlation with CT and histopathology

    International Nuclear Information System (INIS)

    Kim, Sang Won; Lee, Jeong Min; Kin, Chong Soo; Lee, Sang Hun

    2002-01-01

    To assess the feasibility and safety of using a cooled-tip electrode to perform percutaneous radiofrequency ablation of kidney tissue in rabbits, and to evaluate the ability of CT to reveal the appearance and extent of tissue necrosis during follow-up after ablation. Using ultrasound guidance, a 17-G cooled-tip electrode was inserted into the right lower portion of the kidney in 26 New Zealand White rabbits. Radiofrequency was applied for 2 mins, and biphasic helical CT scanning was used to assess tissue destruction and the presence or absence of complications immediately after the procedure and at 24 hrs, 2 and 3 days, and 1,2,3,4,5,6 and 7 weeks. The study had three phases: acute (immediately killed : N=10); subacute (killed at 24 hrs (n=3), 2 days (n=3), 3 days (n=1) : N=7); chronic (killed at 1 week (n=4), 2 weeks (n=2), 4 weeks (n=1), 7 weeks (n=1): N=8). After the animals were killed, their kidneys were histopathologically examined and the radiologic and pathologic findings of lesion size and configuration were correlated. In each instance, ultrasound-guided radiofrequency ablations of the lower pole of the kidney were technically successful. Contrast-enhanced biphasic helical CT revealed regions of hypoattenuation devoid of parenchymal enhancement, and these correlated closely with true pathologic lesion size (r=0.884; p>0.05). In subacute and chronic models, CT scanning revealed gradual spontaneous resorption of the ablated lesion and the presence of perilesional calcification. Histopathologically, in the acute phase the ablated lesion showed coagulative necrosis and infiltration of inflammatory cells, and in the chronic phase there was clear cut necrosis of glomeruli, tubules and renal interstitium, with diminishing inflammatory response and peripheral fibrotic tissue formation. Ultrasound-guided renal radiofrequency ablation is technically feasible and safe. In addition, the avascular lesion measured at contrast-enhanced helical CT closely correlated with

  19. Percutaneous CT-guided high-dose brachytherapy (CT-HDRBT) ablation of primary and metastatic lung tumors in nonsurgical candidates; Perkutane CT-gesteuerte Hochdosis-Brachytherapie (CT-HDRBT) von primaeren und metastatischen Lungentumoren in nicht chirurgischen Kandidaten

    Energy Technology Data Exchange (ETDEWEB)

    Collettini, F.; Schnapauff, D.; Poellinger, A.; Denecke, T.; Banzer, J.; Golenia, M.J.; Gebauer, B. [Charite - Universitatesmedizin Berlin (Germany). Inst. fuer Radiologie; Wust, P. [Charite - Universitatesmedizin Berlin (Germany). Klinik fuer Strahlentherapie

    2012-04-15

    To evaluate the safety and efficacy of CT-guided high-dose brachytherapy (CT-HDRBT) ablation of primary and metastatic lung tumors. Between November 2007 and May 2010, all consecutive patients with primary or metastatic lung tumors, unsuitable for surgery, were treated with CT-HDRBT. Imaging follow-up after treatment was performed with contrast-enhanced CT at 6 weeks, 3 months and every 6 months after the procedure. The endpoints of the study were local tumor control and time to progression. The Kaplan-Meier method was used to estimate survival functions and local tumor progression rates. 34 procedures were carried out on 33 lesions in 22 patients. The mean diameter of the tumors was 33.3 mm (SD = 20.4). The first contrast-enhanced CT showed that complete ablation was achieved in all lesions. The mean minimal tumor enclosing dose was 18.9 Gy (SD = 2). Three patients developed a pneumothorax after the procedure. The mean follow-up time was 13.7 (3 - 29) months. 2 of 32 lesions (6.25 %) developed a local tumor progression. 8 patients (36.3 %) developed a distant tumor progression. After 17.7 months, 13 patients were alive and 9 patients had died. CT-HDRBT ablation is a safe and attractive treatment option for patients with lung malignancies and allows targeted destruction of tumor tissue with simultaneous preservation of important lung structures. Furthermore, CT-HDRBT is independent of the size of the lesion and its location within the lung parenchyma. (orig.)

  20. Intravoxel Incoherent Motion Diffusion Weighted MR Imaging for Monitoring the Instantly Therapeutic Efficacy of Radiofrequency Ablation in Rabbit VX2 Tumors without Evident Links between Conventional Perfusion Weighted Images.

    Directory of Open Access Journals (Sweden)

    Ziyi Guo

    Full Text Available To investigate the intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI as a potential valuable marker to monitor the therapy responses of VX2 to radiofrequency ablation (RF Ablation.The institutional animal care and use committee approved this study. In 10 VX2 tumor-bearing rabbits, IVIM-DWI examinations were performed with a 3.0T imaging unit by using 16 b values from 0 to 800 sec/mm2. The true diffusion coefficient (D, pseudodiffusion coefficient (D* and perfusion fraction (f of tumors were compared between before and instantly after RF Ablation treatment. The differences of D, D* and f and conventional perfusion parameters (from perfusion CT and dynamic enhanced magnetic resonance imaging, DCE-MRI in the coagulation necrosis area, residual unablated area, untreated area, and normal control had been calculated by compared t-test. The correlation between f or D* with perfusion weighted CT including blood flow, BF (milliliter per 100 mL/min, blood volume, BV (milliliter per 100 mL/min, and capillary permeability-surface area, PMB (as a fraction or from DCE-MRI: transfer constant (Ktrans, extra-vascular extra-cellular volume fraction (Ve and reflux constant (Kep values had been analyzed by region-of-interest (ROI methods to calculate Pearson's correlation coefficients.In the ablated necrosis areas, f and D* significantly decreased and D significantly increased, compared with residual unblazed areas or untreated control groups and normal control groups (P < 0.001. The IVIM-DWI derived f parameters showed significant increases in the residual unablated tumor area. There was no significant correlations between f or D* and conventional perfusion parameters.The IVIM-DW derived f, D and D* parameters have the potential to indicate therapy response immediately after RF Ablation treatment, while no significant correlations with classical tumor perfusion metrics were derived from DCE-MRI and perfusion-CT measurements.

  1. Conformal Ablative Thermal Protection System for Small and Large Scale Missions: Approaching TRL 6 for Planetary and Human Exploration Missions and TRL 9 for Small Probe Missions

    Science.gov (United States)

    Beck, R. A. S.; Gasch, M. J.; Milos, F. S.; Stackpoole, M. M.; Smith, B. P.; Switzer, M. R.; Venkatapathy, E.; Wilder, M. C.; Boghhozian, T.; Chavez-Garcia, J. F.

    2015-01-01

    In 2011, NASAs Aeronautics Research Mission Directorate (ARMD) funded an effort to develop an ablative thermal protection system (TPS) material that would have improved properties when compared to Phenolic Impregnated Carbon Ablator (PICA) and AVCOAT. Their goal was a conformal material, processed with a flexible reinforcement that would result in similar or better thermal characteristics and higher strain-to-failure characteristics that would allow for easier integration on flight aeroshells than then-current rigid ablative TPS materials. In 2012, NASAs Space Technology Mission Directorate (STMD) began funding the maturation of the best formulation of the game changing conformal ablator, C-PICA. Progress has been reported at IPPW over the past three years, describing C-PICA with a density and recession rates similar to PICA, but with a higher strain-to-failure which allows for direct bonding and no gap fillers, and even more important, with thermal characteristics resulting in half the temperature rise of PICA. Overall, C-PICA should be able to replace PICA with a thinner, lighter weight, less complicated design. These characteristics should be particularly attractive for use as backshell TPS on high energy planetary entry vehicles. At the end of this year, the material should be ready for missions to consider including in their design, in fact, NASAs Science Mission Directorate (SMD) is considering incentivizing the use of C-PICA in the next Discovery Proposal call. This year both scale up of the material to large (1-m) sized pieces and the design and build of small probe heatshields for flight tests will be completed. NASA, with an industry partner, will build a 1-m long manufacturing demonstration unit (MDU) with a shape based on a mid LD lifting body. In addition, in an effort to fly as you test and test as you fly, NASA, with a second industry partner, will build a small probe to test in the Interactive Heating Facility (IHF) arc jet and, using nearly the

  2. The effect of pre-vertebroplasty tumor ablation using laser-induced thermotherapy on biomechanical stability and cement fill in the metastatic spine.

    Science.gov (United States)

    Ahn, Henry; Mousavi, Payam; Chin, Lee; Roth, Sandra; Finkelstein, Joel; Vitken, Alex; Whyne, Cari

    2007-08-01

    A biomechanical study comparing simulated lytic vertebral metastases treated with laser-induced thermotherapy (LITT) and vertebroplasty versus vertebroplasty alone. To investigate the effect of tumor ablation using LITT prior to vertebroplasty on biomechanical stability and cement fill patterns in a standardized model of spinal metastatic disease. Vertebroplasty in the metastatic spine is aimed at reducing pain, but is associated with risk of cement extravasation in up to 10%. Six pairs of fresh-frozen cadaveric thoracolumbar spinal motion segments were tested in axial compression intact, with simulated metastases and following percutaneous vertebroplasty with or without LITT. Canal narrowing under load, pattern of cement fill, load to failure, and LITT temperature and pressure generation were collected. In all LITT specimens, cement filled the defect without extravasation. The canal extravasation rate was 33% in specimens treated without LITT. LITT and vertebroplasty yielded a trend toward improved posterior wall stability (P = 0.095) as compared to vertebroplasty alone. Moderate rises in temperature and minimal pressure generation was seen during LITT. In this model, elimination of tumor by LITT, facilitates cement fill, enhances biomechanical stability and reduces the risk of cement extravasation.

  3. Ablative skin resurfacing.

    Science.gov (United States)

    Agrawal, Nidhi; Smith, Greg; Heffelfinger, Ryan

    2014-02-01

    Ablative laser resurfacing has evolved as a safe and effective treatment for skin rejuvenation. Although traditional lasers were associated with significant thermal damage and lengthy recovery, advances in laser technology have improved safety profiles and reduced social downtime. CO2 lasers remain the gold standard of treatment, and fractional ablative devices capable of achieving remarkable clinical improvement with fewer side effects and shorter recovery times have made it a more practical option for patients. Although ablative resurfacing has become safer, careful patient selection and choice of suitable laser parameters are essential to minimize complications and optimize outcomes. This article describes the current modalities used in ablative laser skin resurfacing and examines their efficacy, indications, and possible side effects. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  4. [Radiofrequency ablation of hepatocellular carcinoma].

    Science.gov (United States)

    Widmann, Gerlig; Schullian, Peter; Bale, Reto

    2013-03-01

    Percutaneous radiofrequency ablation (RFA) is well established in the treatment of hepatocellular carcinoma (HCC). Due to its curative potential, it is the method of choice for non resectable BCLC (Barcelona Liver Clinic) 0 and A. RFA challenges surgical resection for small HCC and is the method of choice in bridging for transplantation and recurrence after resection or transplantation. The technical feasibility of RFA depends on the size and location of the HCC and the availability of ablation techniques (one needle techniques, multi-needle techniques). More recently, stereotactic multi-needle techniques with 3D trajectory planning and guided needle placement substantially improve the spectrum of treatable lesions including large volume tumors. Treatment success depends on the realization of ablations with large intentional margins of tumor free tissue (A0 ablation in analogy to R0 resection), which has to be documented by fusion of post- with pre-ablation images, and confirmed during follow-up imaging.

  5. Diagnostic accuracy of contrast-enhanced ultrasound in assessing the therapeutic response to radio frequency ablation for liver tumors: systematic review and meta-analysis.

    Science.gov (United States)

    Xuan, Min; Zhou, Fengsheng; Ding, Yan; Zhu, Qiaoying; Dong, Ji; Zhou, Hao; Cheng, Jun; Jiang, Xiao; Wu, Pengxi

    2018-04-01

    To review the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) used to detect residual or recurrent liver tumors after radiofrequency ablation (RFA). This technique uses contrast-enhanced computer tomography or/and contrast-enhanced magnetic resonance imaging as the gold standard of investigation. MEDLINE, EMBASE, and COCHRANE were systematically searched for all potentially eligible studies comparing CEUS with the reference standard that follows RFA. Risk of bias and applicability concerns were addressed by adopting the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Pooled point estimates for sensitivity, specificity, positive and negative likelihood ratios, and diagnostic odds ratios (DOR) with 95% CI were computed before plotting the sROC (summary receiver operating characteristic) curve. Meta-regression and subgroup analysis were used to identify the source of the heterogeneity that was detected. Publication bias was evaluated using Deeks' funnel plot asymmetry test. Ten eligible studies on 1162 lesions that occurred between 2001 and 2016 were included in the final analysis. The quality of the included studies assessed by the QUADAS-2 tool was considered reasonable. The pooled sensitivity and specificity of CEUS in detecting residual or recurrent liver tumors had the following values: 0.90 (95% CI 0.85-0.94) and 1.00 (95% CI 0.99-1.00), respectively. Overall DOR was 420.10 (95% CI 142.30-1240.20). The sources of heterogeneity could not be precisely identified by meta-regression or subgroup analysis. No evidence of publication bias was found. This study confirmed that CEUS exhibits high sensitivity and specificity in assessing therapeutic responses to RFA for liver tumors.

  6. T1 ρ mapping for the evaluation of high intensity focused ultrasound tumor treatment

    NARCIS (Netherlands)

    Hectors, Stefanie J. C. G.; Moonen, Rik P. M.; Strijkers, Gustav J.; Nicolay, Klaas

    2015-01-01

    This study was aimed to assess the effects of High Intensity Focused Ultrasound (HIFU) thermal ablation on tumor T1ρ . In vivo T1ρ measurements of murine tumors at various spin-lock amplitudes (B1 = 0-2000 Hz) were performed before (n = 13), directly after (n = 13) and 3 days (n = 7) after HIFU

  7. Radiofrequency Ablation of Hepatic Cysts : Case Report

    International Nuclear Information System (INIS)

    Lee, Ye Ri; Kim, Pyo Nyun

    2005-01-01

    Radiofrequency ablation has been frequently performed on intra-hepatic solid tumor, namely, hepatocellular carcinoma, metastatic tumor and cholangio carcinoma, for take the cure. But, the reports of radiofrequency ablation for intrahepatic simple cysts are few. In vitro experiment of animal and in vivo treatment for intrahepatic cysts of human had been reported in rare cases. We report 4 cases of radiofrequency ablation for symptomatic intrahepatic cysts

  8. Yttrium-90 radioembolization using TheraSphere in the management of primary and secondary liver tumors.

    Science.gov (United States)

    Riaz, A; Lewandowski, R J; Kulik, L; Salem, R

    2009-06-01

    Locoregional therapies, such as transarterial chemoembolization, radioembolization and thermal ablation (e.g., radiofrequency ablation) are establishing their roles in the management of liver malignancies. With yYttrium-90 radioembolization therapy (90Y) radionuclide labeled microspheres are injected into the tumor feeding artery. This allows the delivery of a high radioactive dose to the tumor with minimal toxicity to normal tissues. 90Y has demonstrated to be safe and effective in the management of liver tumors. Authors present a review of the literature available for the use of TheraSphere for radioembolization in the management of liver tumors.

  9. MR-Guided Laser Ablation of Osteoid Osteoma in an Open High-Field System (1.0 T)

    International Nuclear Information System (INIS)

    Streitparth, F.; Gebauer, B.; Melcher, I.; Schaser, K.; Philipp, C.; Rump, J.; Hamm, B.; Teichgraeber, U.

    2009-01-01

    Computed tomography is the standard imaging modality to minimize the extent of surgical or ablative treatment in osteoid osteomas. In the last 15 years, since a description of thermal ablation of osteoid osteomas was first published, this technique has become a treatment of choice for this tumor. We report the case of a 20-year-old man with an osteoid osteoma treated with laser ablation in an open high-field magnetic resonance imaging scanner (1.0 T). The tumor, located in the right fibula, was safely and effectively ablated under online monitoring. We describe the steps of this interventional procedure and discuss related innovative guidance and monitoring features and potential benefits compared with computed tomographic guidance.

  10. Hemocoagulase Combined with Microbubble-Enhanced Ultrasound Cavitation for Augmented Ablation of Microvasculature in Rabbit VX2 Liver Tumors.

    Science.gov (United States)

    Yang, Qian; Tang, Peng; He, Guangbin; Ge, Shuping; Liu, Liwen; Zhou, Xiaodong

    2017-08-01

    We investigated a new method for combining microbubble-enhanced ultrasound cavitation (MEUC) with hemocoagulase (HC) atrox. Our goal was to induce embolic effects in the vasculature and combine these with an anti-angiogenic treatment strategy. Fourteen days after being implanted with a single slice of the liver VX2 tumor, rabbits were randomly divided into five groups: (i) a control group injected intra-venously with saline using a micropump; (ii) a group given only an injection of HC; (iii) a group treated only with ultrasound cavitation; (iv) a group treated with MEUC; (v) a group treated with MEUC + HC. Contrast-enhanced ultrasound was performed before treatment and 1 h and 7 d post-treatment to measure tumor size, enhancement and necrosis range. QontraXt software was used to determine the time-intensity curve of tumor blood perfusion and microvascular changes. At 1 h and 7 d after treatment with MEUC + HC, the parameters of the time-intensity curve, which included peak value, regional blood volume, regional blood flow and area under the curve value and which were measured using contrast-enhanced ultrasound, were significantly lower than those of the other treatment groups. The MEUC + HC treatment group exhibited significant growth inhibition relative to the ultrasound cavitation only, HC and MEUC treatment groups. No damage was observed in the surrounding normal tissues. These results support the feasibility of reducing the blood perfusion of rabbit VX2 liver tumors using a new method that combines MEUC and HC. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. All rights reserved.

  11. A cooled water-irrigated intraesophageal balloon to prevent thermal injury during cardiac ablation: experimental study based on an agar phantom

    International Nuclear Information System (INIS)

    Lequerica, Juan L; Berjano, Enrique J; Herrero, Maria; Melecio, Lemuel; Hornero, Fernando

    2008-01-01

    A great deal of current research is directed to finding a way to minimize thermal injury in the esophagus during radiofrequency catheter ablation of the atrium. A recent clinical study employing a cooling intraesophageal balloon reported a reduction of the temperature in the esophageal lumen. However, it could not be determined whether the deeper muscular layer of the esophagus was cooled enough to prevent injury. We built a model based on an agar phantom in order to experimentally study the thermal behavior of this balloon by measuring the temperature not only on the balloon, but also at a hypothetical point between the esophageal lumen and myocardium (2 mm distant). Controlled temperature (55 0 C) ablations were conducted for 120 s. The results showed that (1) the cooling balloon provides a reduction in the final temperature reached, both on the balloon surface and at a distance of 2 mm; (2) coolant temperature has a significant effect on the temperature measured at 2 mm from the esophageal lumen (it has a less effect on the temperature measured on the balloon surface) and (3) the pre-cooling period has a significant effect on the temperature measured on the balloon surface (the effect on the temperature measured 2 mm away is small). The results were in good agreement with those obtained in a previous clinical study. The study suggests that the cooling balloon gives thermal protection to the esophagus when a minimum pre-cooling period of 2 min is programmed at a coolant temperature of 5 deg. C or less. (note)

  12. Stereotactic ablative radiotherapy for comprehensive treatment of oligometastatic tumors (SABR-COMET): Study protocol for a randomized phase II trial

    International Nuclear Information System (INIS)

    Palma, David A; Griffioen, GwendolynHMJ; Gaede, Stewart; Slotman, Ben; Senan, Suresh; Haasbeek, Cornelis J A; Rodrigues, George B; Dahele, Max; Lock, Michael; Yaremko, Brian; Olson, Robert; Liu, Mitchell; Panarotto, Jason

    2012-01-01

    Stereotactic ablative radiotherapy (SABR) has emerged as a new treatment option for patients with oligometastatic disease. SABR delivers precise, high-dose, hypofractionated radiotherapy, and achieves excellent rates of local control. Survival outcomes for patients with oligometastatic disease treated with SABR appear promising, but conclusions are limited by patient selection, and the lack of adequate controls in most studies. The goal of this multicenter randomized phase II trial is to assess the impact of a comprehensive oligometastatic SABR treatment program on overall survival and quality of life in patients with up to 5 metastatic cancer lesions, compared to patients who receive standard of care treatment alone. After stratification by the number of metastases (1-3 vs. 4-5), patients will be randomized between Arm 1: current standard of care treatment, and Arm 2: standard of care treatment + SABR to all sites of known disease. Patients will be randomized in a 1:2 ratio to Arm 1:Arm 2, respectively. For patients receiving SABR, radiotherapy dose and fractionation depends on the site of metastasis and the proximity to critical normal structures. This study aims to accrue a total of 99 patients within four years. The primary endpoint is overall survival, and secondary endpoints include quality of life, toxicity, progression-free survival, lesion control rate, and number of cycles of further chemotherapy/systemic therapy. This study will provide an assessment of the impact of SABR on clinical outcomes and quality of life, to determine if long-term survival can be achieved for selected patients with oligometastatic disease, and will inform the design of a possible phase III study. Clinicaltrials.gov identifier: NCT01446744

  13. Cardiac ablation

    Directory of Open Access Journals (Sweden)

    Kelly Ratheal

    2016-01-01

    Full Text Available Cardiac ablation is a procedure that uses either radiofrequency or cryothermal energy to destroy cells in the heart to terminate and/or prevent arrhythmias. The indications for cardiac catheter ablation include refractory, symptomatic arrhythmias, with more specific guidelines for atrial fibrillation in particular. The ablation procedure itself involves mapping the arrhythmia and destruction of the aberrant pathway in an effort to permanently prevent the arrhythmia. There are many types of arrhythmias, and they require individualized approaches to ablation based on their innately different electrical pathways. Ablation of arrhythmias, such as Wolff-Parkinson-White syndrome, AV nodal reentrant tachycardia, and atrial-fibrillation, is discussed in this review. Ablation has a high success rate overall and minimal complication rates, leading to improved quality of life in many patients.

  14. A cooled intraesophageal balloon to prevent thermal injury during endocardial surgical radiofrequency ablation of the left atrium: a finite element study

    Energy Technology Data Exchange (ETDEWEB)

    Berjano, Enrique J [Center for Research and Innovation on Bioengineering, Valencia Polytechnic University, Camino de Vera s/n, 46022 Valencia (Spain); Hornero, Fernando [Cardiac Surgery Department, Valencia University General Hospital, Avd Tres Cruces s/n, 46014, Valencia (Spain)

    2005-10-21

    Recent clinical studies on intraoperative monopolar radiofrequency ablation of atrial fibrillation have reported some cases of injury to the esophagus. The aim of this study was to perform computer simulations using three-dimensional finite element models in order to investigate the feasibility of a cooled intraesophageal balloon appropriately placed to prevent injury. The models included atrial tissue and a fragment of esophagus and lung linked by connective tissue. The lesion depth in the esophagus was assessed using a 50 deg. C isotherm and expressed as a percentage of thickness of the esophageal wall. The results are as follows: (1) chilling the esophagus by means of a cooled balloon placed in the lumen minimizes the lesion in the esophageal wall compared to the cases in which no balloon is used (a collapsed esophagus) and with a non-cooled balloon; (2) the temperature of the cooling fluid has a more significant effect on the minimization of the lesion than the rate of cooling (the thermal transfer coefficient for forced convection); and (3) pre-cooling periods previous to RF ablation do not represent a significant improvement. Finally, the results also suggest that the use of a cooled balloon could affect the transmurality of the atrial lesion, especially in the cases where the atrium is of considerable thickness. (note)

  15. Quantitative Assessment of Variational Surface Reconstruction from Sparse Point Clouds in Freehand 3D Ultrasound Imaging during Image-Guided Tumor Ablation

    Directory of Open Access Journals (Sweden)

    Shuangcheng Deng

    2016-04-01

    Full Text Available Surface reconstruction for freehand 3D ultrasound is used to provide 3D visualization of a VOI (volume of interest during image-guided tumor ablation surgery. This is a challenge because the recorded 2D B-scans are not only sparse but also non-parallel. To solve this issue, we established a framework to reconstruct the surface of freehand 3D ultrasound imaging in 2011. The key technique for surface reconstruction in that framework is based on variational interpolation presented by Greg Turk for shape transformation and is named Variational Surface Reconstruction (VSR. The main goal of this paper is to evaluate the quality of surface reconstructions, especially when the input data are extremely sparse point clouds from freehand 3D ultrasound imaging, using four methods: Ball Pivoting, Power Crust, Poisson, and VSR. Four experiments are conducted, and quantitative metrics, such as the Hausdorff distance, are introduced for quantitative assessment. The experiment results show that the performance of the proposed VSR method is the best of the four methods at reconstructing surface from sparse data. The VSR method can produce a close approximation to the original surface from as few as two contours, whereas the other three methods fail to do so. The experiment results also illustrate that the reproducibility of the VSR method is the best of the four methods.

  16. Non-thermal desorption/ablation of molecular solids induced by ultra-short soft x-ray pulses

    Czech Academy of Sciences Publication Activity Database

    Chalupský, Jaromír; Juha, Libor; Hájková, Věra; Cihelka, Jaroslav; Vyšín, Luděk; Gautier, J.; Hajdu, J.; Hau-Riege, S.P.; Jurek, M.; Krzywinski, J.; London, R.A.; Papalazarou, E.; Pelka, J. B.; Rey, G.; Sebban, S.; Sobierajski, R.; Stojanovic, N.; Tiedtke, K.; Toleikis, S.; Tschentscher, T.; Valentin, C.; Wabnitz, H.; Zeitoun, P.

    2009-01-01

    Roč. 17, č. 1 (2009), s. 208-217 ISSN 1094-4087 R&D Projects: GA AV ČR KAN300100702; GA MŠk LC510; GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR IAA400100701 Grant - others:EU FP6 NEST-Adventure(XE) 012843 Institutional research plan: CEZ:AV0Z10100523 Keywords : x-ray laser * high-order harmonics * free-electron laser * desorption * ablation * organic polymer Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.278, year: 2009

  17. Enhanced laser thermal ablation for the in vitro treatment of liver cancer by specific delivery of multiwalled carbon nanotubes functionalized with human serum albumin.

    Science.gov (United States)

    Iancu, Cornel; Mocan, Lucian; Bele, Constantin; Orza, Anamaria Ioana; Tabaran, Flaviu A; Catoi, Cornel; Stiufiuc, Rares; Stir, Ariana; Matea, Cristian; Iancu, Dana; Agoston-Coldea, Lucia; Zaharie, Florin; Mocan, Teodora

    2011-01-17

    The main goal of this investigation was to develop and test a new method of treatment for human hepatocellular carcinoma (HCC). We present a method of carbon nanotube-enhanced laser thermal ablation of HepG2 cells (human hepatocellular liver carcinoma cell line) based on a simple multiwalled carbon nanotube (MWCNT) carrier system, such as human serum albumin (HSA), and demonstrate its selective therapeutic efficacy compared with normal hepatocyte cells. Both HepG2 cells and hepatocytes were treated with HSA-MWCNTs at various concentrations and at various incubation times and further irradiated using a 2 W, 808 nm laser beam. Transmission electron, phase contrast, and confocal microscopy combined with immunochemical staining were used to demonstrate the selective internalization of HSA-MWCNTs via Gp60 receptors and the caveolin-mediated endocytosis inside HepG2 cells. The postirradiation apoptotic rate of HepG2 cells treated with HSA-MWCNTs ranged from 88.24% (for 50 mg/L) at 60 sec to 92.34% (for 50 mg/L) at 30 min. Significantly lower necrotic rates were obtained when human hepatocytes were treated with HSA-MWCNTs in a similar manner. Our results clearly show that HSA-MWCNTs selectively attach on the albondin (aka Gp60) receptor located on the HepG2 membrane, followed by an uptake through a caveolin-dependent endocytosis process. These unique results may represent a major step in liver cancer treatment using nanolocalized thermal ablation by laser heating.

  18. Temperature mapping and thermal dose calculation in combined radiation therapy and 13.56 MHz radiofrequency hyperthermia for tumor treatment

    Science.gov (United States)

    Kim, Jung Kyung; Prasad, Bibin; Kim, Suzy

    2017-02-01

    To evaluate the synergistic effect of radiotherapy and radiofrequency hyperthermia therapy in the treatment of lung and liver cancers, we studied the mechanism of heat absorption and transfer in the tumor using electro-thermal simulation and high-resolution temperature mapping techniques. A realistic tumor-induced mouse anatomy, which was reconstructed and segmented from computed tomography images, was used to determine the thermal distribution in tumors during radiofrequency (RF) heating at 13.56 MHz. An RF electrode was used as a heat source, and computations were performed with the aid of the multiphysics simulation platform Sim4Life. Experiments were carried out on a tumor-mimicking agar phantom and a mouse tumor model to obtain a spatiotemporal temperature map and thermal dose distribution. A high temperature increase was achieved in the tumor from both the computation and measurement, which elucidated that there was selective high-energy absorption in tumor tissue compared to the normal surrounding tissues. The study allows for effective treatment planning for combined radiation and hyperthermia therapy based on the high-resolution temperature mapping and high-precision thermal dose calculation.

  19. High Retention and Safety of Percutaneously Implanted Endovascular Embolization Coils as Fiducial Markers for Image-Guided Stereotactic Ablative Radiotherapy of Pulmonary Tumors

    International Nuclear Information System (INIS)

    Hong, Julian C.; Yu Yao; Rao, Aarti K.; Dieterich, Sonja; Maxim, Peter G.; Le, Quynh-Thu; Diehn, Maximilian; Sze, Daniel Y.; Kothary, Nishita; Loo, Billy W.

    2011-01-01

    Purpose: To compare the retention rates of two types of implanted fiducial markers for stereotactic ablative radiotherapy (SABR) of pulmonary tumors, smooth cylindrical gold 'seed' markers ('seeds') and platinum endovascular embolization coils ('coils'), and to compare the complication rates associated with the respective implantation procedures. Methods and Materials: We retrospectively analyzed the retention of percutaneously implanted markers in 54 consecutive patients between January 2004 and June 2009. A total of 270 markers (129 seeds, 141 coils) were implanted in or around 60 pulmonary tumors over 59 procedures. Markers were implanted using a percutaneous approach under computed tomography (CT) guidance. Postimplantation and follow-up imaging studies were analyzed to score marker retention relative to the number of markers implanted. Markers remaining near the tumor were scored as retained. Markers in a distant location (e.g., pleural space) were scored as lost. CT imaging artifacts near markers were quantified on radiation therapy planning scans. Results: Immediately after implantation, 140 of 141 coils (99.3%) were retained, compared to 110 of 129 seeds (85.3%); the difference was highly significant (p < 0.0001). Of the total number of lost markers, 45% were reported lost during implantation, but 55% were lost immediately afterwards. No additional markers were lost on longer-term follow-up. Implanted lesions were peripherally located for both seeds (mean distance, 0.33 cm from pleural surface) and coils (0.34 cm) (p = 0.96). Incidences of all pneumothorax (including asymptomatic) and pneumothorax requiring chest tube placement were lower in implantation of coils (23% and 3%, respectively) vs. seeds (54% and 29%, respectively; p = 0.02 and 0.01). The degree of CT artifact was similar between marker types. Conclusions: Retention of CT-guided percutaneously implanted coils is significantly better than that of seed markers. Furthermore, implanting coils is at

  20. Thermal ablation of a confluent lesion in the porcine kidney with a clinically available MR-HIFU system

    Science.gov (United States)

    van Breugel, J. M. M.; de Greef, M.; Wijlemans, J. W.; Schubert, G.; van den Bosch, M. A. A. J.; Moonen, C. T. W.; Ries, M. G.

    2017-07-01

    The incidence of small renal masses (SRMs) sized  weighted MR (T 1 w) imaging. Cell viability staining was performed to visualize the extent of necrosis. Results: a median NPV of 0.62 ml was observed on CE-T 1 w images (IQR 0.58-1.57 ml, range 0.33-2.75 ml). Cell viability staining showed a median damaged volume of 0.59 ml (IQR 0.24-1.35 ml, range 0-4.1 ml). Overlooking of the false rib, shivering of the pig, and too large depth combined with a large heat-sink effect resulted in insufficient heating in 4 cases. The NPV and necrosed volume were confluent in all cases in which an ablated volume could be observed. Our results demonstrated the feasibility of creating a confluent volume of ablated kidney cortical tissue in vivo with MR-HIFU on a clinically available system using respiratory gating and near-field cooling and showed its reproducibility.

  1. Analysis of the effect of renal excretory system cooling during thermal radiofrequency ablation in an animal model

    Directory of Open Access Journals (Sweden)

    Andre Meireles

    2014-01-01

    Full Text Available Objective: Analysis of renal excretory system integrity and efficacy of radiofrequency ablation with and without irrigation with saline at 2 o C (SF2. Materials and Methods: The median third of sixteen kidneys were submitted to radiofrequency (exposition of 1 cm controlled by intra-surgical ultrasound, with eight minutes cycles and median temperature of 90 o C in eight female pigs. One excretory renal system was cooled with SF2, at a 30ml/min rate, and the other kidney was not. After 14 days of post-operatory, the biggest diameters of the lesions and the radiological aspects of the excretory system were compared by bilateral ascending pyelogram and the animals were sacrificed in order to perform histological analysis. Results: There were no significant differences between the diameters of the kidney lesions whether or not exposed to cooling of the excretory system. Median diameter of the cooled kidneys and not cooled kidneys were respectively (in mm: anteroposterior: 11.46 vs. 12.5 (p = 0.23; longitudinal: 17.94 vs. 18.84 (p = 0.62; depth: 11.38 vs. 12.25 (p = 0.47. There was no lesion of the excretory system or signs of leakage of contrast media or hydronephrosis at ascending pyelogram. Conclusion: Cooling of excretory system during radiofrequency ablation does not significantly alter generated coagulation necrosis or affect the integrity of the excretory system in the studied model.

  2. Power Laser Ablation Symposia

    CERN Document Server

    Phipps, Claude

    2007-01-01

    Laser ablation describes the interaction of intense optical fields with matter, in which atoms are selectively driven off by thermal or nonthermal mechanisms. The field of laser ablation physics is advancing so rapidly that its principal results are seen only in specialized journals and conferences. This is the first book that combines the most recent results in this rapidly advancing field with authoritative treatment of laser ablation and its applications, including the physics of high-power laser-matter interaction. Many practical applications exist, ranging from inertial confinement fusion to propulsion of aerostats for pollution monitoring to laser ignition of hypersonic engines to laser cleaning nanoscale contaminants in high-volume computer hard drive manufacture to direct observation of the electronic or dissociative states in atoms and molecules, to studying the properties of materials during 200kbar shocks developed in 200fs. Selecting topics which are representative of such a broad field is difficu...

  3. The Use of Tensor Fascia Lata Pedicled Flap in Reconstructing Full Thickness Abdominal Wall Defects and Groin Defects Following Tumor Ablation

    International Nuclear Information System (INIS)

    Rifaat, M.A.; Abdel Gawad, W.S.

    2005-01-01

    The tensor fascia lata is a versatile flap with many uses in reconstructive plastic surgery. As a pedicled flap its reach to the lower abdomen and groin made it an attractive option for reconstructing soft tissue defects after tumor ablation. However, debate exists on the safe dimension of the flap, as distal tip necrosis is common. Also, the adequacy of the fascia lata as a sole substitute for abdominal wall muscles has been disputable. The aim of the current study is to report our experience and clinical observations with this flap in reconstructing those challenging defects and to discuss the possible options to minimize the latter disputable issues. Patients and Methods: From April 2001 to April 2004, 12 pedicled TFL flaps were used to reconstruct 5 central abdominal wall full thickness defects and 6 groin soft tissue defects following tumor resection. ]n one case, bilateral flaps were used to reconstruct a large central abdominal wall defect. There were 4 males and 7 females. Their age ranged from 19 to 60. From the abdominal wall defects group, all repairs were enforced primarily with a prolene mesh except for one patient who was the first in this study. Patients presenting with groin defects required coverage of exposed vessels following tumor resection. All patients in the current study underwent immediate reconstruction. The resulting soft tissue defects in this study were due to resection of 4 abdominal wall desmoid tumors, a colonic carcinoma infiltrating the abdominal wall, 4 primary groin soft developed in a flap used to cover a groin defect. In the former 3 cases, The flap was simply transposed without complete islanding of the flap. In the latter case, a very large flap was harvested beyond the safe limits with its distal edge just above the knee. In addition, wound dehiscence of the flap occurred in 2 other cases from the groin group. Nevertheless, all the wounds healed spontaneously with repeated dressings. Out of the 5 cases that underwent

  4. Hydrodynamic instabilities in an ablation front

    International Nuclear Information System (INIS)

    Piriz, A R; Portugues, R F

    2004-01-01

    The hydrodynamic stability of an ablation front is studied for situations in which the wavelength of the perturbations is larger than the distance to the critical surface where the driving radiation is absorbed. An analytical model is presented, and it shows that under conditions in which the thermal flux is limited within the supercritical region of the ablative corona, the front may behave like a flame or like an ablation front, depending on the perturbation wavelength. For relatively long wavelengths the critical and ablation surfaces practically lump together into a unique surface and the front behaves like a flame, whereas for the shortest wavelengths the ablation front substructure is resolved

  5. Hydrodynamic instabilities in an ablation front

    Energy Technology Data Exchange (ETDEWEB)

    Piriz, A R; Portugues, R F [E.T.S.I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain)

    2004-06-01

    The hydrodynamic stability of an ablation front is studied for situations in which the wavelength of the perturbations is larger than the distance to the critical surface where the driving radiation is absorbed. An analytical model is presented, and it shows that under conditions in which the thermal flux is limited within the supercritical region of the ablative corona, the front may behave like a flame or like an ablation front, depending on the perturbation wavelength. For relatively long wavelengths the critical and ablation surfaces practically lump together into a unique surface and the front behaves like a flame, whereas for the shortest wavelengths the ablation front substructure is resolved.

  6. Fiber Optic Sensors for Temperature Monitoring during Thermal Treatments: An Overview

    Science.gov (United States)

    Schena, Emiliano; Tosi, Daniele; Saccomandi, Paola; Lewis, Elfed; Kim, Taesung

    2016-01-01

    During recent decades, minimally invasive thermal treatments (i.e., Radiofrequency ablation, Laser ablation, Microwave ablation, High Intensity Focused Ultrasound ablation, and Cryo-ablation) have gained widespread recognition in the field of tumor removal. These techniques induce a localized temperature increase or decrease to remove the tumor while the surrounding healthy tissue remains intact. An accurate measurement of tissue temperature may be particularly beneficial to improve treatment outcomes, because it can be used as a clear end-point to achieve complete tumor ablation and minimize recurrence. Among the several thermometric techniques used in this field, fiber optic sensors (FOSs) have several attractive features: high flexibility and small size of both sensor and cabling, allowing insertion of FOSs within deep-seated tissue; metrological characteristics, such as accuracy (better than 1 °C), sensitivity (e.g., 10 pm·°C−1 for Fiber Bragg Gratings), and frequency response (hundreds of kHz), are adequate for this application; immunity to electromagnetic interference allows the use of FOSs during Magnetic Resonance- or Computed Tomography-guided thermal procedures. In this review the current status of the most used FOSs for temperature monitoring during thermal procedure (e.g., fiber Bragg Grating sensors; fluoroptic sensors) is presented, with emphasis placed on their working principles and metrological characteristics. The essential physics of the common ablation techniques are included to explain the advantages of using FOSs during these procedures. PMID:27455273

  7. Fiber Optic Sensors for Temperature Monitoring during Thermal Treatments: An Overview

    Directory of Open Access Journals (Sweden)

    Emiliano Schena

    2016-07-01

    Full Text Available During recent decades, minimally invasive thermal treatments (i.e., Radiofrequency ablation, Laser ablation, Microwave ablation, High Intensity Focused Ultrasound ablation, and Cryo-ablation have gained widespread recognition in the field of tumor removal. These techniques induce a localized temperature increase or decrease to remove the tumor while the surrounding healthy tissue remains intact. An accurate measurement of tissue temperature may be particularly beneficial to improve treatment outcomes, because it can be used as a clear end-point to achieve complete tumor ablation and minimize recurrence. Among the several thermometric techniques used in this field, fiber optic sensors (FOSs have several attractive features: high flexibility and small size of both sensor and cabling, allowing insertion of FOSs within deep-seated tissue; metrological characteristics, such as accuracy (better than 1 °C, sensitivity (e.g., 10 pm·°C−1 for Fiber Bragg Gratings, and frequency response (hundreds of kHz, are adequate for this application; immunity to electromagnetic interference allows the use of FOSs during Magnetic Resonance- or Computed Tomography-guided thermal procedures. In this review the current status of the most used FOSs for temperature monitoring during thermal procedure (e.g., fiber Bragg Grating sensors; fluoroptic sensors is presented, with emphasis placed on their working principles and metrological characteristics. The essential physics of the common ablation techniques are included to explain the advantages of using FOSs during these procedures.

  8. Percutaneous radiofrequency ablation of osteoid osteomas. Technique and results

    International Nuclear Information System (INIS)

    Bruners, P.; Penzkofer, T.; Guenther, R. W.; Mahnken, A.

    2009-01-01

    Purpose: Osteoid osteoma is a benign primary bone tumor that typically occurs in children and young adults. Besides local pain, which is often worse at night, prompt relief due to medication with acetylsalicylic acid (ASS) is characteristic for this bone lesion. Because long-term medication with ASS does not represent an alternative treatment strategy due to its potentially severe side effects, different minimally invasive image-guided techniques for the therapy of osteoid osteoma have been developed. In this context radiofrequency (RF) ablation in particular has become part of the clinical routine. The technique and results of image-guided RF ablation are compared to alternative treatment strategies. Materials and Methods: Using this technique, an often needle-shaped RF applicator is percutaneously placed into the tumor under image guidance. Then a high-frequency alternating current is applied by the tip of the applicator which leads to ionic motion within the tissue resulting in local heat development and thus in thermal destruction of the surrounding tissue including the tumor. Results: The published primary and secondary success rates of this technique are 87 and 83%, respectively. Surgical resection and open curettage show comparable success rates but are associated with higher complication rates. In addition image-guided RF ablation of osteoid osteomas is associated with low costs. (orig.)

  9. Enhanced laser thermal ablation for the in vitro treatment of liver cancer by specific delivery of multiwalled carbon nanotubes functionalized with human serum albumin

    Directory of Open Access Journals (Sweden)

    Cornel Iancu

    2011-01-01

    Full Text Available Cornel Iancu1, Lucian Mocan1, Constantin Bele2, Anamaria Ioana Orza2, Flaviu A Tabaran3, Cornel Catoi3, Rares Stiufiuc4, Ariana Stir1, Cristian Matea2, Dana Iancu1, Lucia Agoston-Coldea1, Florin Zaharie1, Teodora Mocan11Department of Nanomedicine, 'Iuliu Hatieganu' University of Medicine and Pharmacy, Third Surgery Clinic, Cluj-Napoca, Romania; 2Department of Biochemistry, 3Department of Pathology, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, Romania; 4Department of Biophysics, 'Iuliu Hatieganu' University of Medicine and Pharmacy, Cluj-Napoca, RomaniaAbstract: The main goal of this investigation was to develop and test a new method of treatment for human hepatocellular carcinoma (HCC. We present a method of carbon nanotube-enhanced laser thermal ablation of HepG2 cells (human hepatocellular liver carcinoma cell line based on a simple multiwalled carbon nanotube (MWCNT carrier system, such as human serum albumin (HSA, and demonstrate its selective therapeutic efficacy compared with normal hepatocyte cells. Both HepG2 cells and hepatocytes were treated with HSA–MWCNTs at various concentrations and at various incubation times and further irradiated using a 2 W, 808 nm laser beam. Transmission electron, phase contrast, and confocal microscopy combined with immunochemical staining were used to demonstrate the selective internalization of HSA–MWCNTs via Gp60 receptors and the caveolin-mediated endocytosis inside HepG2 cells. The postirradiation apoptotic rate of HepG2 cells treated with HSA–MWCNTs ranged from 88.24% (for 50 mg/L at 60 sec to 92.34% (for 50 mg/L at 30 min. Significantly lower necrotic rates were obtained when human hepatocytes were treated with HSA–MWCNTs in a similar manner. Our results clearly show that HSA–MWCNTs selectively attach on the albondin (aka Gp60 receptor located on the HepG2 membrane, followed by an uptake through a caveolin-dependent endocytosis

  10. Non-invasive method for screening and early detection of breast tumors using thermal field analysis

    Directory of Open Access Journals (Sweden)

    O. Drosu

    2009-10-01

    Full Text Available The paper refers to general presentation of international and European evaluation regarding breast cancer incidence and mortality as well as recommendations for prevention, screening, detection and treatment.The past years international research development in biomedical engineering has put a particular emphasis on the thermography use in breast pathology diagnosis and its main advantages, such as: an early diagnose of the breast cancer, in that stage when the mammography or ultrasounds can not easily detect the changes of the tissue; a totally non-invasive interaction with human body; very low costs and possibilities for the women to do a self thermographic test.We also present some important results of our research within the field of breast tumor detection using the numerical analysis of the thermal inverse problem.

  11. Radio-frequency ablation in patients with malignant hepatic tumor and experimental model: comparison of expandable needle and water-cooled needle

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Yong Ju; Jeong, Yong Yeon; Kim, Jeong; Yim, Nam yeol; Kang, Heoung Keun [School of Medicine, Chonnam National Univ., Gwangju (Korea, Republic of); Kim, Eun Ha; Yoon, Kwon Ha [School of Medicine, Wonkwang Univ., Iksan (Korea, Republic of); Ko, Seog Wan [School of Medicine, Chonbuk National Univ., Jeonju (Korea, Republic of)

    2004-12-01

    The purpose of this study was to compare the shape and volume of the radio-frequency induced lesions produced by two commercially available radio-frequency ablation (RFA) systems, the expandable and cooled-tip needles, in clinical patients and an experimental model. A twelve-array anchor expandable needle electrode and a single cooled-tip needle electrode were used to treat hepatic tumors with a single session in 23 patients (20 hepatocellular carcinomas and 3 hepatic metastases) and fourteen patients (10 hepatocellular carcinomas and 4 hepatic metastases), respectively. Twenty RFA induced lesions were created with each system in 10 explanted bovine livers. The shape of the RFA induced lesions were divided into oval lesions along or perpendicular to the axis of the electrode and spherical lesions, and we then calculated the volumes of the RFA induced lesions. Fourteen (61%) lesions of the 23 patients treated with the expandable system were oval perpendicular to the axis of the electrode and nine (39%) of the lesions were spherical. All the lesions (100%) of the 14 patients treated with the cooled-tip needle were ovaI along the axis of the electrode. In the ex vivo bovine livers, the shape of the all RFA induced lesions was oval perpendicular to the axis of the electrode for the expandable needle, and oval along the axis of the electrode for the cooled-tip needle. The mean diameter and volume of the RFA induced lesions in the patients were 3.35{+-}0.56 cm and 19.9{+-}6.53 cm{sup 3}, respectively, for the expandable needle and 3.58{+-}0.78 cm and 23.19{+-}5.27 cm{sup 3}, respectively, for the cooled-tip needle. In the ex vivo model, the mean diameter and volume of RFA induced lesions were 3.41{+-}0.59 cm and 26.59{+-}8.02 cm{sup 3}, respectively, for the expandable needle, and 4.04{+-}0.65 cm and 33.82{+-}6.16 cm{sup 3}, respectively, for the cooled-tip needle (p <0.05). These results indicate that the shape of RFA induced lesions with the expandable needle were oval

  12. Real-time Tumor Oxygenation Changes After Single High-dose Radiation Therapy in Orthotopic and Subcutaneous Lung Cancer in Mice: Clinical Implication for Stereotactic Ablative Radiation Therapy Schedule Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Song, Changhoon [Department of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Hong, Beom-Ju; Bok, Seoyeon; Lee, Chan-Ju; Kim, Young-Eun [Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, Gyeongbuk (Korea, Republic of); Jeon, Sang-Rok [Department of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine, Seoul (Korea, Republic of); Wu, Hong-Gyun [Department of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine, Seoul (Korea, Republic of); Institute of Radiation Medicine, Medical Research Center, Seoul National University College of Medicine, Seoul (Korea, Republic of); Lee, Yun-Sang [Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Department of Molecular Medicine and Biopharmaceutical Sciences, Seoul National University College of Medicine, Seoul (Korea, Republic of); Cheon, Gi Jeong; Paeng, Jin Chul [Cancer Research Institute, Seoul National University College of Medicine, Seoul (Korea, Republic of); Institute of Radiation Medicine, Medical Research Center, Seoul National University College of Medicine, Seoul (Korea, Republic of); Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Carlson, David J. [Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut (United States); and others

    2016-07-01

    Purpose: To investigate the serial changes of tumor hypoxia in response to single high-dose irradiation by various clinical and preclinical methods to propose an optimal fractionation schedule for stereotactic ablative radiation therapy. Methods and Materials: Syngeneic Lewis lung carcinomas were grown either orthotopically or subcutaneously in C57BL/6 mice and irradiated with a single dose of 15 Gy to mimic stereotactic ablative radiation therapy used in the clinic. Serial [{sup 18}F]-misonidazole (F-MISO) positron emission tomography (PET) imaging, pimonidazole fluorescence-activated cell sorting analyses, hypoxia-responsive element-driven bioluminescence, and Hoechst 33342 perfusion were performed before irradiation (day −1), at 6 hours (day 0), and 2 (day 2) and 6 (day 6) days after irradiation for both subcutaneous and orthotopic lung tumors. For F-MISO, the tumor/brain ratio was analyzed. Results: Hypoxic signals were too low to quantitate for orthotopic tumors using F-MISO PET or hypoxia-responsive element-driven bioluminescence imaging. In subcutaneous tumors, the maximum tumor/brain ratio was 2.87 ± 0.483 at day −1, 1.67 ± 0.116 at day 0, 2.92 ± 0.334 at day 2, and 2.13 ± 0.385 at day 6, indicating that tumor hypoxia was decreased immediately after irradiation and had returned to the pretreatment levels at day 2, followed by a slight decrease by day 6 after radiation. Pimonidazole analysis also revealed similar patterns. Using Hoechst 33342 vascular perfusion dye, CD31, and cleaved caspase 3 co-immunostaining, we found a rapid and transient vascular collapse, which might have resulted in poor intratumor perfusion of F-MISO PET tracer or pimonidazole delivered at day 0, leading to decreased hypoxic signals at day 0 by PET or pimonidazole analyses. Conclusions: We found tumor hypoxia levels decreased immediately after delivery of a single dose of 15 Gy and had returned to the pretreatment levels 2 days after irradiation and had decreased

  13. Dynamics of tissue shrinkage during ablative temperature exposures

    International Nuclear Information System (INIS)

    Rossmann, Christian; Haemmerich, Dieter; Garrett-Mayer, Elizabeth; Rattay, Frank

    2014-01-01

    There is a lack of studies that examine the dynamics of heat-induced shrinkage of organ tissues. Clinical procedures such as radiofrequency ablation, microwave ablation or high-intensity focused ultrasound, use heat to treat diseases such as cancer and cardiac arrhythmia. When heat is applied to tissues, shrinkage occurs due to protein denaturation, dehydration and contraction of collagen at temperatures greater 50 °C. This is particularly relevant for image-guided procedures such as tumor ablation, where pre- and post-treatment images are compared and any changes in dimensions must be considered to avoid misinterpretations of the treatment outcome. We present data from ex vivo, isothermal shrinkage tests in porcine liver tissue, where axial changes in tissue length were recorded during 15 min of heating to temperatures between 60 and 95 °C. A mathematical model was developed to accurately describe the time and temperature-dependent shrinkage behavior. The shrinkage dynamics had the same characteristics independent of temperature; the estimated relative shrinkage, adjusted for time since death, after 15 min heating to temperatures of 60, 65, 75, 85 and 95 °C, was 12.3, 13.8, 16.6, 19.2 and 21.7%, respectively. Our results demonstrate the shrinkage dynamics of organ tissues, and suggest the importance of considering tissue shrinkage for thermal ablative treatments. (paper)

  14. Considering Angle Selection When Using Ultrasound Electrode Displacement Elastography to Evaluate Radiofrequency Ablation of Tissues

    Science.gov (United States)

    Li, Qiang; Chen, Pin-Yu; Wang, Chiao-Yin; Liu, Hao-Li; Teng, Jianfu

    2014-01-01

    Percutaneous radiofrequency ablation (RFA) is a minimally invasive treatment to thermally destroy tumors. Ultrasound-based electrode-displacement elastography is an emerging technique for evaluating the region of RFA-induced lesions. The angle between the imaging probe and the RFA electrode can influence electrode-displacement elastography when visualizing the ablation zone. We explored the angle effect on electrode-displacement elastography to measure the ablation zone. Phantoms embedded with meatballs were fabricated and then ablated using an RFA system to simulate RFA-induced lesions. For each phantom, a commercial ultrasound scanner with a 7.5 MHz linear probe was used to acquire raw image data at different angles, ranging from 30° to 90° at increments of 10°, to construct electrode-displacement images and facilitate comparisons with tissue section images. The results revealed that the ablation regions detected using electrode-displacement elastography were highly correlated with those from tissue section images when the angle was between 30° and 60°. However, the boundaries of lesions were difficult to distinguish, when the angle was larger than 60°. The experimental findings suggest that angle selection should be considered to achieve reliable electrode-displacement elastography to describe ablation zones. PMID:24971347

  15. Non-coaxial-based microwave ablation antennas for creating symmetric and asymmetric coagulation zones

    Science.gov (United States)

    Mohtashami, Yahya; Luyen, Hung; Hagness, Susan C.; Behdad, Nader

    2018-06-01

    We present an investigation of a new class of microwave ablation (MWA) antennas capable of producing axially symmetric or asymmetric heating patterns. The antenna design is based on a dipole fed by a balanced parallel-wire transmission line. The angle and direction of the deployed dipole arms are used to control the heating pattern. We analyzed the specific absorption rate and temperature profiles using electromagnetic and thermal simulations. Two prototypes were fabricated and tested in ex vivo ablation experiments: one was designed to produce symmetric heating patterns and the other was designed to generate asymmetric heating patterns. Both fabricated prototypes exhibited good impedance matching and produced localized coagulation zones as predicted by the simulations. The prototype operating in porcine muscle created an ˜10 cm3 symmetric ablation zone after 10 min of ablation with a power level of 18 W. The prototype operating in egg white created an ˜4 cm3 asymmetric ablation zone with a directionality ratio of 40% after 5 min of ablation with a power level of 25 W. The proposed MWA antenna design shows promise for minimally invasive treatment of tumors in various clinical scenarios where, depending on the situation, a symmetric or an asymmetric heating pattern may be needed.

  16. No-touch radiofrequency ablation: A comparison of switching bipolar and switching monopolar ablation in Ex Vivo bovine liver

    International Nuclear Information System (INIS)

    Chang, Won; Lee, Jeong Min; Lee, Sang Min; Hank, Joon Koo

    2017-01-01

    To evaluate the feasibility, efficiency, and safety of no-touch switching bipolar (SB) and switching monopolar (SM) radiofrequency ablation (RFA) using ex vivo bovine livers. A pork loin cube was inserted as a tumor mimicker in the bovine liver block; RFA was performed using the no-touch technique in the SM (group A1; 10 minutes, n = 10, group A2; 15 minutes, n = 10) and SB (group B; 10 minutes, n = 10) modes. The groups were compared based on the creation of confluent necrosis with sufficient safety margins, the dimensions, and distance between the electrode and ablation zone margin (DEM). To evaluate safety, small bowel loops were placed above the liver surface and 30 additional ablations were performed in the same groups. Confluent necroses with sufficient safety margins were created in all specimens. SM RFA created significantly larger volumes of ablation compared to SB RFA (all p < 0.001). The DEM of group B was significantly lower than those of groups A1 and A2 (all p < 0.001). Although thermal injury to the small bowel was noted in 90%, 100%, and 30% of the cases in groups A1, A2, and B, respectively, full depth injury was noted only in 60% of group A2 cases. The no-touch RFA technique is feasible in both the SB and SM modes; however, SB RFA appears to be more advantageous compared to SM RFA in the creation of an ablation zone while avoiding the unnecessary creation of an adjacent parenchymal ablation zone or adjacent small bowel injuries

  17. No-touch radiofrequency ablation: A comparison of switching bipolar and switching monopolar ablation in Ex Vivo bovine liver

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Won; Lee, Jeong Min; Lee, Sang Min; Hank, Joon Koo [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2017-04-15

    To evaluate the feasibility, efficiency, and safety of no-touch switching bipolar (SB) and switching monopolar (SM) radiofrequency ablation (RFA) using ex vivo bovine livers. A pork loin cube was inserted as a tumor mimicker in the bovine liver block; RFA was performed using the no-touch technique in the SM (group A1; 10 minutes, n = 10, group A2; 15 minutes, n = 10) and SB (group B; 10 minutes, n = 10) modes. The groups were compared based on the creation of confluent necrosis with sufficient safety margins, the dimensions, and distance between the electrode and ablation zone margin (DEM). To evaluate safety, small bowel loops were placed above the liver surface and 30 additional ablations were performed in the same groups. Confluent necroses with sufficient safety margins were created in all specimens. SM RFA created significantly larger volumes of ablation compared to SB RFA (all p < 0.001). The DEM of group B was significantly lower than those of groups A1 and A2 (all p < 0.001). Although thermal injury to the small bowel was noted in 90%, 100%, and 30% of the cases in groups A1, A2, and B, respectively, full depth injury was noted only in 60% of group A2 cases. The no-touch RFA technique is feasible in both the SB and SM modes; however, SB RFA appears to be more advantageous compared to SM RFA in the creation of an ablation zone while avoiding the unnecessary creation of an adjacent parenchymal ablation zone or adjacent small bowel injuries.

  18. In vivo photoacoustics and high frequency ultrasound imaging of mechanical high intensity focused ultrasound (HIFU) ablation.

    Science.gov (United States)

    Daoudi, Khalid; Hoogenboom, Martijn; den Brok, Martijn; Eikelenboom, Dylan; Adema, Gosse J; Fütterer, Jürgen J; de Korte, Chris L

    2017-04-01

    The thermal effect of high intensity focused ultrasound (HIFU) has been clinically exploited over a decade, while the mechanical HIFU is still largely confined to laboratory investigations. This is in part due to the lack of adequate imaging techniques to better understand the in-vivo pathological and immunological effects caused by the mechanical treatment. In this work, we explore the use of high frequency ultrasound (US) and photoacoustics (PA) as a potential tool to evaluate the effect of mechanical ablation in-vivo , e.g. boiling histotripsy. Two mice bearing a neuroblastoma tumor in the right leg were ablated using an MRI-HIFU system conceived for small animals and monitored using MRI thermometry. High frequency US and PA imaging were performed before and after the HIFU treatment. Afterwards, the tumor was resected for further assessment and evaluation of the ablated region using histopathology. High frequency US imaging revealed the presence of liquefied regions in the treated area together with fragmentized tissue which appeared with different reflecting proprieties compared to the surrounding tissue. Photoacoustic imaging on the other hand revealed the presence of deoxygenated blood within the tumor after the ablation due to the destruction of blood vessel network while color Doppler imaging confirmed the blood vessel network destruction within the tumor. The treated area and the presence of red blood cells detected by photoacoustics were further confirmed by the histopathology. This feasibility study demonstrates the potential of high frequency US and PA approach for assessing in-vivo the effect of mechanical HIFU tumor ablation.

  19. Flat-Panel Cone-Beam Ct-Guided Radiofrequency Ablation of Very Small (≤1.5 cm) Liver Tumors: Technical Note on a Preliminary Experience

    Energy Technology Data Exchange (ETDEWEB)

    Cazzato, Roberto Luigi, E-mail: r.cazzato@unicampus.it; Buy, Xavier, E-mail: x.buy@bordeaux.unicancer.fr; Alberti, Nicolas, E-mail: nicoalbertibdx@gmail.com; Fonck, Mariane, E-mail: m.fonk@bordeaux.unicancer.fr [Institut Bergonié 229 Cours de l’Argonne, Department of Radiology (France); Grasso, Rosario Francesco, E-mail: r.grasso@unicampus.it [Università “Campus Bio-Medico di Roma”, Department of Radiology and Diagnostic Imaging (Italy); Palussière, Jean, E-mail: j.palussiere@bordeaux.unicancer.fr [Institut Bergonié 229 Cours de l’Argonne, Department of Radiology (France)

    2015-02-15

    PurposeThe aim of the present study was to investigate the technical feasibility of flat-panel cone-beam CT (CBCT)-guided radiofrequency ablation (RFA) of very small (<1.5 cm) liver tumors.Materials and MethodsPatients included were candidates for hepatic percutaneous RFA as they had single biopsy-proven hepatic tumors sized ≤1.5 cm and poorly defined on ultrasonography. Following apnea induction, unenhanced CBCT scans were acquired and used to deploy the RF electrode with the aid of a virtual navigation system. If the tumor was not clearly identified on the unenhanced CBCT scan, a right retrograde arterial femoral access was established to carry out hepatic angiography and localize the tumor. Patients’ lesions and procedural variables were recorded and analyzed.ResultsThree patients (2 male and 1 female), aged 68, 76, and 87 years were included; 3 lesions (2 hepato-cellular carcinoma and 1 metastasis from colorectal cancer) were treated. One patient required hepatic angiography. Cycles of apnea used to acquire CBCT images and to deploy the electrode lasted <120 s. Mean fluoroscopic time needed to deploy the electrode was 36.6 ± 5.7 min. Mean overall procedural time was 66.0 ± 22.9 min. No peri- or post-procedural complications were noted. No cases of incomplete ablation were noted at 1-month follow-up.ConclusionPercutaneous CBCT-guided liver RFA with or without arterial hepatic angiography is technically feasible.

  20. Laserinduced interstitial thermotherapy (LITT) of malignant liver tumors. Is it possible to gauge energy requirement for ablation with the aid of Hounsfield units?

    International Nuclear Information System (INIS)

    Hilberg, Anja

    2011-01-01

    Many malignant tumors such as colorectal cancer or breast cancer cause liver metastases. The therapy strategy is dependent on the primary tumor. Laser induced Interstitial Thermotherapy (LITT), together with various other minimally invasive approaches, is a thermotherapy and could be applied in addition to surgery or as the exclusive method of treating isolated liver metastases. Major advantages of such an approach are the possibility of implementing an outpatient scheme, as well as a lower occurrence rate of complications. After a CT-controlled puncture of the metastases the therapy is monitored in the MRI by using thermosensitive sequences. Liver tissue absorbs energy from laser photons; heat caused by this effect leads to the destruction of tumorous tissue. As the amount of energy required to destroy the metastases varies greatly even with the volume of lesions being the same, the aim of this paper is to find out whether there is a relation between energy requirement and liver density as gauged by means of CT before treatment. For this purpose 168 patients with 279 liver metastases originating from different primaries who were treated with LITT between March 2006 and March 2007 were included in this study. 55.4 % of the patients were pretreated with TACE, which reduces the blood flow in the liver, thus reducing amount of energy required from laser photon treatment. Prior to every single LITT sequence liver density was gauged by puncture CT with the aid of Hounsfield units; also, the volume of the induced necrosis in the 24h MRI image and in the control MRI after 3, 6 and 12 months was measured. It was possible to calculate the actual energy consumption on the basis of number, running time and energy output of the laser employed. Check-up examinations showed a decrease of the mean necrosis-volumes, which indicates that absence of recurrence of the tumor in those spots that had been laser-treated. Analysis of the average survival time after the first LITT over an

  1. High-speed scanning ablation of dental hard tissues with a λ = 9.3 μm CO2 laser: adhesion, mechanical strength, heat accumulation, and peripheral thermal damage

    Science.gov (United States)

    Nguyen, Daniel; Chang, Kwang; Hedayatollahnajafi, Saba; Staninec, Michal; Chan, Kenneth; Lee, Robert; Fried, Daniel

    2011-07-01

    CO2 lasers can be operated at high laser pulse repetition rates for the rapid and precise removal of dental decay. Excessive heat accumulation and peripheral thermal damage is a concern when using high pulse repetition rates. Peripheral thermal damage can adversely impact the mechanical strength of the irradiated tissue, particularly for dentin, and reduce the adhesion characteristics of the modified surfaces. The interpulpal temperature rise was recorded using microthermocouples situated at the roof of the pulp chamber on teeth that were occlusally ablated using a rapidly-scanned CO2 laser operating at 9.3 μm with a pulse duration of 10 to 15 μs and repetition rate of 300 Hz over a 2 min time course. The adhesion strength of laser treated enamel and dentin surfaces was measured for various laser scanning parameters with and without post-ablation acid etching using the single-plane shear test. The mechanical strength of laser-ablated dentin surfaces were determined via the four-point bend test and compared to control samples prepared with 320 grit wet sand paper to simulate conventional preparations. Thermocouple measurements indicated that the temperature remained below ambient temperature if water-cooling was used. There was no discoloration of either dentin or enamel laser treated surfaces, the surfaces were uniformly ablated, and there were no cracks visible. Four-point bend tests yielded mean mechanical strengths of 18.2 N (s.d. = 4.6) for ablated dentin and 18.1 N (s.d. = 2.7) for control (p > 0.05). Shear tests yielded mean bond strengths approaching 30 MPa for both enamel and dentin under certain irradiation conditions. These values were slightly lower than nonirradiated acid-etched control samples. Additional studies are needed to determine if the slightly lower bond strength than the acid-etched control samples is clinically significant. These measurements demonstrate that enamel and dentin surfaces can be rapidly ablated by CO2 lasers with minimal

  2. Radiofrequency-induced thermal therapy: results of a European multicentre study of resistive ablation of incompetent truncal varicose veins.

    Science.gov (United States)

    Braithwaite, B; Hnatek, L; Zierau, U; Camci, M; Akkersdijk, Gjm; Nio, D; Sarlija, M; Ajduk, M; Santoro, P; Roche, E

    2013-02-01

    To investigate the effectiveness of bipolar radiofrequency-induced thermal therapy (RFITT) in a multicentre non-randomized study. Some 672 incompetent saphenous veins (85% great saphenous varicose vein, 15% short saphenous vein) in 462 patients (56.5% CEAP [clinical, aetiological, anatomical and pathological elements] class 3 or worse) were treated in eight European centres. Patients were assessed between 180 and 360 days postoperatively. Occlusion rates were determined by duplex ultrasound and compared with the power used for treatment, pull back rate and experience of the operating surgeon. Complete occlusion rates of 98.4% were achieved when treatments were performed by an experienced operator (more than 20 cases), when the maximum power setting on the RFITT generator was between 18 and 20 W and the applicator was withdrawn at a rate slower than 1.5 second/cm RFITT is efficacious, well tolerated by patients and has a low incidence of procedure-related post-operative complications.

  3. TU-B-210-02: MRg HIFU - Advanced Approaches for Ablation and Hyperthermia

    Energy Technology Data Exchange (ETDEWEB)

    Moonen, C. [University Medical Center Utrecht (Netherlands)

    2015-06-15

    MR guided focused ultrasound (MRgFUS), or alternatively high-intensity focused ultrasound (MRgHIFU), is approved for thermal ablative treatment of uterine fibroids and pain palliation in bone metastases. Ablation of malignant tumors is under active investigation in sites such as breast, prostate, brain, liver, kidney, pancreas, and soft tissue. Hyperthermia therapy with MRgFUS is also feasible, and may be used in conjunction with radiotherapy and for local targeted drug delivery. MRI allows in situ target definition and provides continuous temperature monitoring and subsequent thermal dose mapping during HIFU. Although MRgHIFU can be very precise, treatment of mobile organs is challenging and advanced techniques are required because of artifacts in MR temperature mapping, the need for intercostal firing, and need for gated HIFU or tracking of the lesion in real time. The first invited talk, “MR guided Focused Ultrasound Treatment of Tumors in Bone and Soft Tissue”, will summarize the treatment protocol and review results from treatment of bone tumors. In addition, efforts to extend this technology to treat both benign and malignant soft tissue tumors of the extremities will be presented. The second invited talk, “MRI guided High Intensity Focused Ultrasound – Advanced Approaches for Ablation and Hyperthermia”, will provide an overview of techniques that are in or near clinical trials for thermal ablation and hyperthermia, with an emphasis of applications in abdominal organs and breast, including methods for MRTI and tracking targets in moving organs. Learning Objectives: Learn background on devices and techniques for MR guided HIFU for cancer therapy Understand issues and current status of clinical MRg HIFU Understand strategies for compensating for organ movement during MRgHIFU Understand strategies for strategies for delivering hyperthermia with MRgHIFU CM - research collaboration with Philips.

  4. Therapeutic efficacy of percutaneous radiofrequency ablation versus microwave ablation for hepatocellular carcinoma.

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    Full Text Available The aim of this study was to investigate the therapeutic efficacy of percutaneous radiofrequency (RF ablation versus microwave (MW ablation for hepatocellular carcinoma (HCC measuring ≤ 5 cm in greatest diameter. From January 2006 to December 2006, 78 patients had undergone RF ablation whereas 77 had undergone MW ablation. Complete ablation (CA, local tumour progression (LTP and distant recurrence (DR were compared. The overall survival curves were calculated with the Kaplan-Meier technique and compared with the log-rank test. The CA rate was 83.4% (78/93 for RF ablation and 86.7%(91/105 for MW ablation. The LTP rate was 11.8% (11/93 for RF ablation and 10.5% (11/105 for MW ablation. DR was found in 51 (65.4% in the RF ablation and 62 (80.5% in the MW ablation. There was no significant difference in the 1-, 3-, and 5-year overall survival rates (P = 0.780 and the 1-, 3-, and 5-year disease-free survival rates (P = 0.123 between RF and MW ablation. At subgroup analyses, for patients with tumors ≤ 3.0 cm, there was no significant difference in the 1-, 3-, and 5-year overall survival rates (P = 0.067 and the corresponding disease-free survival rates(P = 0.849. For patients with tumor diameters of 3.1-5.0 cm, the 1-, 3-, and 5-year overall survival rates were 87.1%, 61.3%, and 40.1% for RF ablation and 85.4%, 36.6%, and 22% for MW ablation, with no significant difference (P = 0.068. The corresponding disease-free survival rates were 74.2%, 54.8%, and 45.2% for the RF ablation group and 53.3%, 26.8%, and 17.1% for the MW ablation group. The disease-free survival curve for the RF ablation group was significantly better than that for the MW ablation group (P = 0.018. RF ablation and MW ablation are both effective methods in treating hepatocellular carcinomas, with no significant differences in CA, LTP, DR, and overall survival.

  5. Adaptive ultrasound temperature imaging for monitoring radiofrequency ablation.

    Directory of Open Access Journals (Sweden)

    Yi-Da Liu

    Full Text Available Radiofrequency ablation (RFA has been widely used as an alternative treatment modality for liver tumors. Monitoring the temperature distribution in the tissue during RFA is required to assess the thermal dosage. Ultrasound temperature imaging based on the detection of echo time shifts has received the most attention in the past decade. The coefficient k, connecting the temperature change and the echo time shift, is a medium-dependent parameter used to describe the confounding effects of changes in the speed of sound and thermal expansion as temperature increases. The current algorithm of temperature estimate based on echo time shift detection typically uses a constant k, resulting in estimation errors when ablation temperatures are higher than 50°C. This study proposes an adaptive-k algorithm that enables the automatic adjustment of the coefficient k during ultrasound temperature monitoring of RFA. To verify the proposed algorithm, RFA experiments on in vitro porcine liver samples (total n = 15 were performed using ablation powers of 10, 15, and 20 W. During RFA, a clinical ultrasound system equipped with a 7.5-MHz linear transducer was used to collect backscattered signals for ultrasound temperature imaging using the constant- and adaptive-k algorithms. Concurrently, an infrared imaging system and thermocouples were used to measure surface temperature distribution of the sample and internal ablation temperatures for comparisons with ultrasound estimates. Experimental results demonstrated that the proposed adaptive-k method improved the performance in visualizing the temperature distribution. In particular, the estimation errors were also reduced even when the temperature of the tissue is higher than 50°C. The proposed adaptive-k ultrasound temperature imaging strategy has potential to serve as a thermal dosage evaluation tool for monitoring high-temperature RFA.

  6. Parameter estimation of brain tumors using intraoperative thermal imaging based on artificial tactile sensing in conjunction with artificial neural network

    International Nuclear Information System (INIS)

    Sadeghi-Goughari, M; Mojra, A; Sadeghi, S

    2016-01-01

    Intraoperative Thermal Imaging (ITI) is a new minimally invasive diagnosis technique that can potentially locate margins of brain tumor in order to achieve maximum tumor resection with least morbidity. This study introduces a new approach to ITI based on artificial tactile sensing (ATS) technology in conjunction with artificial neural networks (ANN) and feasibility and applicability of this method in diagnosis and localization of brain tumors is investigated. In order to analyze validity and reliability of the proposed method, two simulations were performed. (i) An in vitro experimental setup was designed and fabricated using a resistance heater embedded in agar tissue phantom in order to simulate heat generation by a tumor in the brain tissue; and (ii) A case report patient with parafalcine meningioma was presented to simulate ITI in the neurosurgical procedure. In the case report, both brain and tumor geometries were constructed from MRI data and tumor temperature and depth of location were estimated. For experimental tests, a novel assisted surgery robot was developed to palpate the tissue phantom surface to measure temperature variations and ANN was trained to estimate the simulated tumor’s power and depth. Results affirm that ITI based ATS is a non-invasive method which can be useful to detect, localize and characterize brain tumors. (paper)

  7. Intraoperative application of thermal camera for the assessment of during surgical resection or biopsy of human's brain tumors

    Science.gov (United States)

    Kastek, M.; Piatkowski, T.; Polakowski, H.; Kaczmarska, K.; Czernicki, Z.; Bogucki, J.; Zebala, M.

    2014-05-01

    Motivation to undertake research on brain surface temperature in clinical practice is based on a strong conviction that the enormous progress in thermal imaging techniques and camera design has a great application potential. Intraoperative imaging of pathological changes and functionally important areas of the brain is not yet fully resolved in neurosurgery and remains a challenge. A study of temperature changes across cerebral cortex was performed for five patients with brain tumors (previously diagnosed using magnetic resonance or computed tomography) during surgical resection or biopsy of tumors. Taking into account their origin and histology the tumors can be divided into the following types: gliomas, with different degrees of malignancy (G2 to G4), with different metabolic activity and various temperatures depending on the malignancy level (3 patients), hypervascular tumor associated with meninges (meningioma), metastatic tumor - lung cancer with a large cyst and noticeable edema. In the case of metastatic tumor with large edema and a liquid-filled space different temperature of a cerebral cortex were recorded depending on metabolic activity. Measurements have shown that the temperature on the surface of the cyst was on average 2.6 K below the temperature of surrounding areas. It has been also observed that during devascularization of a tumor, i.e. cutting off its blood vessels, the tumor temperature lowers significantly in spite of using bipolar coagulation, which causes additional heat emission in the tissue. The results of the measurements taken intra-operatively confirm the capability of a thermal camera to perform noninvasive temperature monitoring of a cerebral cortex. As expected surface temperature of tumors is different from surface temperature of tissues free from pathological changes. The magnitude of this difference depends on histology and the origin of the tumor. These conclusions lead to taking on further experimental research, implementation

  8. Evaluation of great saphenous vein occlusion rate and clinical outcome in patients undergoing laser thermal ablation with a 1470-nm bare fiber laser with low linear endovenous energy density

    Directory of Open Access Journals (Sweden)

    Walter Junior Boim Araujo

    2015-12-01

    Full Text Available Abstract Background Water-specific 1470-nm lasers enable vein ablation at lower energy densities and with fewer side effects because they target interstitial water in the vessel wall. Objectives To determine great saphenous vein (GSV occlusion rate after thermal ablation with 1470-nm laser using 7W power and to evaluate clinical outcomes and complications. Method Nineteen patients (31 GSVs underwent thermal ablation. Follow-up duplex scanning, clinical evaluation using the Venous Clinical Severity Score (VCSS, and evaluation of procedure-related complications were performed at 3-5 days after the procedure and at 30 and 180 days. Results Mean patient age was 46 years and 17 of the patients were female (89.47%. Of 31 limbs treated, 2 limbs were clinical class C2, 19 were C3, 9 were C4, and 1 limb was C5 according to the Clinical-Etiology-Anatomy-Pathophysiology (CEAP classification. Mean linear endovenous energy density was 33.53 J/cm. The GSV occlusion rate was 93.5% immediately after treatment, 100% at 3-5 days and 100% at 30 days after treatment and 87.1% 180 days after treatment. There was a significant reduction in VCSS at all time points. Conclusions The data from this study support the possibility that the incidence of complications can be reduced without significantly affecting the clinical outcomes, by using lower energy density. However, this appears to be at the cost of reduced efficacy in terms of GSV occlusion rates.

  9. Effects of pressure rise on cw laser ablation of tissue

    Science.gov (United States)

    LeCarpentier, Gerald L.; Motamedi, Massoud; Welch, Ashley J.

    1991-06-01

    The objectives of this research were to identify mechanisms responsible for the initiation of continuous wave (cw) laser ablation of tissue and investigate the role of pressure in the ablation process. Porcine aorta samples were irradiated in a chamber pressurized from 1 X 10-4 to 12 atmospheres absolute pressure. Acrylic and Zn-Se windows in the experimental pressure chamber allowed video and infrared cameras to simultaneously record mechanical and thermal events associated with cw argon laser ablation of these samples. Video and thermal images of tissue slabs documented the explosive nature of cw laser ablation of soft biological media and revealed similar ablation threshold temperatures and ablation onset times under different environmental pressures; however, more violent initiation explosions with decreasing environmental pressures were observed. These results suggest that ablation initiates with thermal alterations in the mechanical strength of the tissue and proceeds with an explosion induced by the presence superheated liquid within the tissue.

  10. Intracranial inertial cavitation threshold and thermal ablation lesion creation using MRI-guided 220-kHz focused ultrasound surgery: preclinical investigation.

    Science.gov (United States)

    Xu, Zhiyuan; Carlson, Carissa; Snell, John; Eames, Matt; Hananel, Arik; Lopes, M Beatriz; Raghavan, Prashant; Lee, Cheng-Chia; Yen, Chun-Po; Schlesinger, David; Kassell, Neal F; Aubry, Jean-Francois; Sheehan, Jason

    2015-01-01

    In biological tissues, it is known that the creation of gas bubbles (cavitation) during ultrasound exposure is more likely to occur at lower rather than higher frequencies. Upon collapsing, such bubbles can induce hemorrhage. Thus, acoustic inertial cavitation secondary to a 220-kHz MRI-guided focused ultrasound (MRgFUS) surgery is a serious safety issue, and animal studies are mandatory for laying the groundwork for the use of low-frequency systems in future clinical trials. The authors investigate here the in vivo potential thresholds of MRgFUS-induced inertial cavitation and MRgFUS-induced thermal coagulation using MRI, acoustic spectroscopy, and histology. Ten female piglets that had undergone a craniectomy were sonicated using a 220-kHz transcranial MRgFUS system over an acoustic energy range of 5600-14,000 J. For each piglet, a long-duration sonication (40-second duration) was performed on the right thalamus, and a short sonication (20-second duration) was performed on the left thalamus. An acoustic power range of 140-300 W was used for long-duration sonications and 300-700 W for short-duration sonications. Signals collected by 2 passive cavitation detectors were stored in memory during each sonication, and any subsequent cavitation activity was integrated within the bandwidth of the detectors. Real-time 2D MR thermometry was performed during the sonications. T1-weighted, T2-weighted, gradient-recalled echo, and diffusion-weighted imaging MRI was performed after treatment to assess the lesions. The piglets were killed immediately after the last series of posttreatment MR images were obtained. Their brains were harvested, and histological examinations were then performed to further evaluate the lesions. Two types of lesions were induced: thermal ablation lesions, as evidenced by an acute ischemic infarction on MRI and histology, and hemorrhagic lesions, associated with inertial cavitation. Passive cavitation signals exhibited 3 main patterns identified as

  11. Outcomes of patients with hepatocellular carcinoma referred for percutaneous radiofrequency ablation at a tertiary center: Analysis focused on the feasibility with the use of ultrasonography guidance

    International Nuclear Information System (INIS)

    Kim, Ji-Eun; Kim, Young-sun; Rhim, Hyunchul; Lim, Hyo K.; Lee, Min Woo; Choi, Dongil; Shin, Sung Wook; Cho, Sung Ki

    2011-01-01

    Purpose: This study aimed to assess the feasibility of performing ultrasonography (US)-guided percutaneous radiofrequency (RF) ablation on patients with hepatocellular carcinoma (HCC) and identify causes of procedure infeasibility and its predisposing conditions. Materials and methods: A total of 109 consecutive patients (male:female = 86:23; mean 59.9 years) with 136 HCCs (mean 1.8 cm) who had been referred for planning US were analyzed. We evaluated overall procedure feasibility as well as specific factors relating to feasibility, including inability to visualize the tumor with US and factors relating to safety of the procedure. Results: The use of percutaneous RF ablation was concluded as infeasible for 45 tumors (33.1%). Reasons for infeasibility included tumor invisibility (n = 32), a high risk of collateral thermal injury (n = 5), absence of a safe electrode path (n = 5) and a combination of factors (n = 3). Among 136 tumors, 36(26.5%) were invisible due to isoechogenicity (n = 16), indiscrimination from surrounding cirrhotic nodules (n = 10) or an unfavorable location (n = 10). Tumor invisibility was significantly attributed to a small tumor size (P < 0.001, risk ratio = 0.823) and the presence of macronodular cirrhosis (P = 0.006, risk ratio = 4.117). Seven patients with invisible tumors were treated with RF ablation after follow-up (n = 4) or with use of adjacent structures as landmarks (n = 3). Ultimately, 65 of 109 patients were treated with percutaneous RF ablation. Conclusions: US-guided percutaneous RF ablation for HCC was feasible in about two-thirds of candidates. Infeasibility was mostly due to inability to visualize the tumor with US, especially for patients with smaller tumor and macronodular cirrhosis.

  12. EF5 PET of Tumor Hypoxia: A Predictive Imaging Biomarker of Response to Stereotactic Ablative Radiotherapy (SABR) for Early Lung Cancer

    Science.gov (United States)

    2017-11-01

    SABR) for Early Lung Cancer PRINCIPAL INVESTIGATOR: Billy W Loo Jr, MD PhD CONTRACTING ORGANIZATION: The Leland Stanford Junior University...Response to Stereotactic Ablative Radiotherapy (SABR) for Early Lung Cancer 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Billy W Loo Jr, MD...for early stage lung cancer in patients who are not candidates for surgery because of excessive surgical risk, and will be an important treatment option

  13. Value of radiofrequency ablation in the treatment of hepatocellular carcinoma

    Science.gov (United States)

    Feng, Kai; Ma, Kuan-Sheng

    2014-01-01

    Hepatocellular carcinoma (HCC) is a malignant disease that substantially affects public health worldwide. It is especially prevalent in east Asia and sub-Saharan Africa, where the main etiology is the endemic status of chronic hepatitis B. Effective treatments with curative intent for early HCC include liver transplantation, liver resection (LR), and radiofrequency ablation (RFA). RFA has become the most widely used local thermal ablation method in recent years because of its technical ease, safety, satisfactory local tumor control, and minimally invasive nature. This technique has also emerged as an important treatment strategy for HCC in recent years. RFA, liver transplantation, and hepatectomy can be complementary to one another in the treatment of HCC, and the outcome benefits have been demonstrated by numerous clinical studies. As a pretransplantation bridge therapy, RFA extends the average waiting time without increasing the risk of dropout or death. In contrast to LR, RFA causes almost no intra-abdominal adhesion, thus producing favorable conditions for subsequent liver transplantation. Many studies have demonstrated mutual interactions between RFA and hepatectomy, effectively expanding the operative indications for patients with HCC and enhancing the efficacy of these approaches. However, treated tumor tissue remains within the body after RFA, and residual tumors or satellite nodules can limit the effectiveness of this treatment. Therefore, future research should focus on this issue. PMID:24876721

  14. Multi-functional system of radiotherapy and thermal phototherapy for tumors that over-express receptors of the gastrin releasing peptide; Sistema multifuncional de radioterapia y fototerapia termica para tumores que sobre-expresan receptores del peptido liberador de gastrina

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez M, N. P.

    2014-07-01

    The aim of this research was to prepare and characterize a multifunctional system of {sup 177}Lu and {sup 99m}Tc-labelled gold nanoparticles conjugated to Tat(49 57)-Lys{sup 3} bombesin ({sup 177}Lu/{sup 99m}Tc- AuNP-Tat-Bn) and to evaluate the radiation absorbed dose in GRP receptor positive PC3 tumours induced in mice (human prostate cancer cells), as well as to evaluate the thermal effect produced by the multifunctional system in PC3 cancer cells. The preparation of the system involved the conjugation of Bn-Tat, DOTA-GGC and HYNICTOC peptides to AuNP of 20 nm or 5 nm in diameter. The radiolabeling of the system with {sup 99m}Tc was carried out through the ligand HYNIC-TOC and with the {sup 177}Lu through DOTA-GGC. The functionalization of peptides to AuNP, was accomplished through a spontaneous reaction of thiol groups. The system was characterized by spectroscopic techniques while radiochemical purity was determined by size-exclusion molecular chromatography and ultrafiltration. Various internalization trials and non-specific binding were tested to demonstrate the affinity of the system to PC3 cells. The thermal effect was evaluated incubating the system into PC3 cells and irradiating it with a Nd:YAG pulsed laser beam and monitoring the temperature; after irradiation, cell viability was measured. In the evaluation of absorbed dose in mice with induced tumours, the system was administered intratumorally and later, mice were sacrificed, relevant organs and tumor were extracted, activity was quantified and radiopharmaceutical models were obtained for each organ and tumor to be used in the accumulated activity and absorbed dose calculation by the MIRD methodology. Finally, to establish the system location at cellular level, fluorescent images of the system incubated in PC3 cells were acquired with an epi fluorescent microscope. Tem, UV-Vis, XP S and Far-IR spectroscopy techniques demonstrated that AuNPs were functionalized with peptides through interactions with

  15. Advanced film-forming gel formula vs spring thermal water and white petrolatum as primary dressings after full-face ablative fractional CO2 laser resurfacing: a comparative split-face pilot study.

    Science.gov (United States)

    Marini, L

    2018-01-01

    Aesthetically pleasing results and fast, uneventful recovery are highly desirable after rejuvenating ablative laser procedures. Wound dressings following ablative laser procedures should ideally improve and optimize the wound healing environment. The purpose of this comparative split-face, single-blinded, prospective observational study was to assess the efficacy and acceptability of two primary wound dressings immediately after a full-face fractional CO 2 laser resurfacing procedure. The assessments of an innovative film-forming dressing called Stratacel (SC) vs spring thermal water + Vaseline (V+) were conducted after a standardized, single-pass, full-face ablative fractional CO 2 laser skin resurfacing procedure. Clinical parameters, such as haemoglobin - HB; surface temperature - ST; micro-textural modifications - MT; superficial melanin - M; intrafollicular porphyrins - P, were assessed at different phases of the healing process using standardized, non-invasive technologies. Five female volunteers were enrolled in this inpatient, controlled pilot study. Most of the clinical parameters considered, including 3D surface texture analysis, revealed a better performance of SC vs. V+ during the early, more delicate phases of the healing process. This preliminary study, even if performed on a small number of volunteers, confirmed a definite advantage of the tested semipermeable film-forming formula (SC) over a more conventional postoperative skin care regime (V+). Clinical results could be explained by a better uniformity of distribution of SC over the micro-irregularities induced by ablative fractional CO 2 laser resurfacing. Its thin, semipermeable film might, in fact, act as an efficient, perfectly biocompatible, full contact, temporary skin barrier, able to protect extremely delicate healing surfaces from potential environmental irritations. © 2017 European Academy of Dermatology and Venereology.

  16. Individualized laparoscopic B-ultrasound-guided microwave ablation for multifocal primary liver cancer.

    Science.gov (United States)

    Xu, Zhifeng; Yang, Zhangwei; Pan, Jianghua; Hu, Yiren

    2018-03-01

    Liver cancer is one of the most common malignancies of the digestive system. Minimally invasive ablation procedures have become one of the major means for treating unresectable multifocal liver cancer and have been extensively applied in primary and metastatic liver cancer treatment. Laparoscopic B-ultrasound-guided microwave ablation is an example of the progress made in this field. To analyze and summarize the results of and experience with laparoscopic B-ultrasound-guided microwave ablation for multifocal primary liver cancer; moreover, the ablation effects were compared between tumors of different sizes. Laparoscope-guided needle ablation was conducted on 84 lesions from 32 patients with primary liver cancer based on tumor size, quantity, and location. Moreover, the perioperative data, ablation effects according to tumor size, and long-term follow-up results were analyzed. Among the 84 nodules treated via microwave ablation, tumors measuring ≤ 3 cm demonstrated complete ablation upon imaging analysis conducted 1 month after surgery. Moreover, 5 of the tumors measuring > 3 cm demonstrated incomplete ablation. In these cases, a second procedure was performed, until imaging studies confirmed that complete ablation was achieved. Laparoscopic microwave ablation allows for precise puncture positioning, an effective ablation range, and safe and feasible surgery, which is especially suitable for liver tumors located in sites difficult to access.

  17. Nanosecond pulsed electric field ablation of hepatocellular carcinoma.

    Science.gov (United States)

    Beebe, Stephen J; Chen, Xinhua; Liu, Jie A; Schoenbach, Karl H

    2011-01-01

    Hepatocellular carcinoma often evades effective therapy and recurrences are frequent. Recently, nanosecond pulsed electric field (nsPEF) ablation using pulse power technology has emerged as a local-regional, non-thermal, and non-drug therapy for skin cancers. In the studies reported here we use nsPEFs to ablate murine, rat and human HCCs in vitro and an ectopic murine Hepa 1-6 HCC in vivo. Using pulses with 60 or 300 ns and electric fields as high as 60 kV/cm, murine Hepa 1-6, rat N1S1 and human HepG2 HCC are readily eliminated with changes in caspase-3 activity. Interestingly caspase activities increase in the mouse and human model and decrease in the rat model as electric field strengths are increased. In vivo, while sham treated control mice survived an average of 15 days after injection and before humane euthanasia, Hepa 1-6 tumors were eliminated for longer than 50 days with 3 treatments using one hundred pulses with 100 ns at 55 kV/cm. Survival was 40% in mice treated with 30 ns pulses at 55 kV/cm. This study demonstrates that nsPEF ablation is not limited to effectively treating skin cancers and provides a rationale for treating orthotopic hepatocellular carcinoma in pre-clinical applications and ultimately in clinical trials.

  18. Investigation of HIFU-induced anti-tumor immunity in a murine tumor model

    Directory of Open Access Journals (Sweden)

    Lyerly H Kim

    2007-07-01

    Full Text Available Abstract Background High intensity focused ultrasound (HIFU is an emerging non-invasive treatment modality for localized treatment of cancers. While current clinical strategies employ HIFU exclusively for thermal ablation of the target sites, biological responses associated with both thermal and mechanical damage from focused ultrasound have not been thoroughly investigated. In particular, endogenous danger signals from HIFU-damaged tumor cells may trigger the activation of dendritic cells. This response may play a critical role in a HIFU-elicited anti-tumor immune response which can be harnessed for more effective treatment. Methods Mice bearing MC-38 colon adenocarcinoma tumors were treated with thermal and mechanical HIFU exposure settings in order to independently observe HIFU-induced effects on the host's immunological response. In vivo dendritic cell activity was assessed along with the host's response to challenge tumor growth. Results Thermal and mechanical HIFU were found to increase CD11c+ cells 3.1-fold and 4-fold, respectively, as compared to 1.5-fold observed for DC injection alone. In addition, thermal and mechanical HIFU increased CFSE+ DC accumulation in draining lymph nodes 5-fold and 10-fold, respectively. Moreover, focused ultrasound treatments not only caused a reduction in the growth of primary tumors, with tumor volume decreasing by 85% for thermal HIFU and 43% for mechanical HIFU, but they also provided protection against subcutaneous tumor re-challenge. Further immunological assays confirmed an enhanced CTL activity and increased tumor-specific IFN-γ-secreting cells in the mice treated by focused ultrasound, with cytotoxicity induced by mechanical HIFU reaching as high as 27% at a 10:1 effector:target ratio. Conclusion These studies present initial encouraging results confirming that focused ultrasound treatment can elicit a systemic anti-tumor immune response, and they suggest that this immunity is closely related to

  19. Efficacy and safety of radiofrequency ablation of hepatocellular carcinoma in the hepatic dome with the CT-guided extrathoracic transhepatic approach

    International Nuclear Information System (INIS)

    Kim, Young Kon; Kim, Chong Soo; Lee, Jeong Min; Chung, Gyung Ho; Chon, Su Bin

    2006-01-01

    Purpose: The purpose of this study was to determine the efficacy and safety of radiofrequency (RF) ablation for the treatment of hepatocellular carcinoma (HCC) in the hepatic dome with CT-guided extrathoracic transhepatic approach. Materials and methods: Fifteen patients with 15 HCCs (size range: 0.8-4 cm, mean size: 1.8 cm) in the hepatic dome were treated by RF ablation using cooled-tip electrodes and with CT-guided extrathoracic transhepatic approach. Therapeutic response of the tumor to RF ablation and procedure-related complications including hepatic injury, hemoperitoneum, and thermal injury of diaphragm were evaluated. Results: The average number of needle punctures to ensure the correct needle position in the targeted tumor was 3.7 (range: 1-6 punctures). The average ablation time was 14.7 min (range: 8-25 min). Complete necrosis without marginal recurrence after at least 13-month follow-up was attained in 13 tumors (86.7%). There were no major complications related to the procedures. Six patients had shoulder pain that lasted three days to two weeks after the procedures and their symptoms were resolved with conservative treatment. Conclusions: RF ablation using CT-guided extrathoracic transhepatic approach is an effective and safe technique for the treatment of HCC in the hepatic dome

  20. Benign thyroid nodule unresponsive to radiofrequency ablation treated with laser ablation: a case report.

    Science.gov (United States)

    Oddo, Silvia; Balestra, Margherita; Vera, Lara; Giusti, Massimo

    2018-05-11

    Radiofrequency ablation and laser ablation are safe and effective techniques for reducing thyroid nodule volume, neck symptoms, and cosmetic complaints. Therapeutic success is defined as a nodule reduction > 50% between 6 and 12 months after the procedure, but a percentage of nodules inexplicably do not respond to thermal ablation. We describe the case of a young Caucasian woman with a solid benign thyroid nodule who refused surgery and who had undergone radiofrequency ablation in 2013. The nodule did not respond in terms of either volume reduction or improvement in neck symptoms. After 2 years, given the patient's continued refusal of thyroidectomy, we proposed laser ablation. The nodule displayed a significant volume reduction (- 50% from radiofrequency ablation baseline volume, - 57% from laser ablation baseline), and the patient reported a significant improvement in neck symptoms (from 6/10 to 1/10 on a visual analogue scale). We conjecture that some benign thyroid nodules may be intrinsically resistant to necrosis when one specific ablation technique is used, but may respond to another technique. To the best of our knowledge, this is the first description of the effect of performing a different percutaneous ablation technique in a nodule that does not respond to radiofrequency ablation.

  1. Induced thermal ablation with a radiofrequency field in breast cancer cells using gold nanoparticles conjugated to the peptide cycle[RGDfK(C)

    International Nuclear Information System (INIS)

    Sanchez H, L.

    2014-01-01

    The conjugation of peptides to gold nanoparticles (AuNP) produces biocompatible and stable multimeric systems with target-specific molecular recognition. Peptides based on the cyclic Arg-Gly-Asp (RGD) sequence have been reported as high-affinity agents for the α(v)β(3) and α(v)β(v) integrin s over expressed in breast cancer cells. AuNP have also been proposed as localized heat sources for cancer treatment using laser irradiation or radiofrequency (RF). The objective of this research was to evaluate the thermo ablative effect of the AuNP-c [RGDfK(C)] system on MCF7 breast cancer cell viability after exposure to a radiofrequency field and to compare it with that produced by the laser irradiation. The effect of the 13.56 MHz RF (using a power from 0 to 200 W at intervals of 50 W) over the temperature increase in AuNP-colloidal system of 5 and 20 nm at two different concentrations was evaluated. The absorption cross sections (C abs ) of the AuNP-c [RGDfK(C)] nano system when it interacts with low frequency electromagnetic waves (13.56 MHz, λ = 22 m) and optical frequency waves (laser at λ = 532 nm) was analyzed based on the Mi e theory. The effect on the MCF7 cell viability was assessed using two thermal conversion sources (Laser and RF) on AuNP-c [RGDfK(C)] located inside the cytoplasm of the cells. MCF7 cells were treated with AuNP-c [RGDfK(C)] or water after exposure to the RF field (200 W, 100 V/cm) or laser irradiation (Irradiance 0.65 W/cm 2 ). In both cases (RF and laser) the presence of nanoparticles internalized inside the cells caused a significant increase in the temperature of the medium (RF: ΔT = 29.9 ± 1.7 grades C for AuNP compared toΔT = 13.0 ± 1.4 grades C for water; laser: ΔT = 13.5 ± 0.7 grades C for AuNP compared to 3.3 ± 0.5 grades C for water). Although RF induced a higher increase in the temperature of the medium with nanoparticles, the largest effect on the cell viability was produced by laser when nanoparticles were located inside

  2. Multi-functional system of radiotherapy and thermal phototherapy for tumors that over-express receptors of the gastrin releasing peptide

    International Nuclear Information System (INIS)

    Jimenez M, N. P.

    2014-01-01

    The aim of this research was to prepare and characterize a multifunctional system of 177 Lu and 99m Tc-labelled gold nanoparticles conjugated to Tat(49 57)-Lys 3 bombesin ( 177 Lu/ 99m Tc- AuNP-Tat-Bn) and to evaluate the radiation absorbed dose in GRP receptor positive PC3 tumours induced in mice (human prostate cancer cells), as well as to evaluate the thermal effect produced by the multifunctional system in PC3 cancer cells. The preparation of the system involved the conjugation of Bn-Tat, DOTA-GGC and HYNICTOC peptides to AuNP of 20 nm or 5 nm in diameter. The radiolabeling of the system with 99m Tc was carried out through the ligand HYNIC-TOC and with the 177 Lu through DOTA-GGC. The functionalization of peptides to AuNP, was accomplished through a spontaneous reaction of thiol groups. The system was characterized by spectroscopic techniques while radiochemical purity was determined by size-exclusion molecular chromatography and ultrafiltration. Various internalization trials and non-specific binding were tested to demonstrate the affinity of the system to PC3 cells. The thermal effect was evaluated incubating the system into PC3 cells and irradiating it with a Nd:YAG pulsed laser beam and monitoring the temperature; after irradiation, cell viability was measured. In the evaluation of absorbed dose in mice with induced tumours, the system was administered intratumorally and later, mice were sacrificed, relevant organs and tumor were extracted, activity was quantified and radiopharmaceutical models were obtained for each organ and tumor to be used in the accumulated activity and absorbed dose calculation by the MIRD methodology. Finally, to establish the system location at cellular level, fluorescent images of the system incubated in PC3 cells were acquired with an epi fluorescent microscope. Tem, UV-Vis, XP S and Far-IR spectroscopy techniques demonstrated that AuNPs were functionalized with peptides through interactions with the -Sh groups. The radiochemical

  3. Femtosecond laser ablation of enamel

    Science.gov (United States)

    Le, Quang-Tri; Bertrand, Caroline; Vilar, Rui

    2016-06-01

    The surface topographical, compositional, and structural modifications induced in human enamel by femtosecond laser ablation is studied. The laser treatments were performed using a Yb:KYW chirped-pulse-regenerative amplification laser system (560 fs and 1030 nm) and fluences up to 14 J/cm2. The ablation surfaces were studied by scanning electron microscopy, grazing incidence x-ray diffraction, and micro-Raman spectroscopy. Regardless of the fluence, the ablation surfaces were covered by a layer of resolidified material, indicating that ablation is accompanied by melting of hydroxyapatite. This layer presented pores and exploded gas bubbles, created by the release of gaseous decomposition products of hydroxyapatite (CO2 and H2O) within the liquid phase. In the specimen treated with 1-kHz repetition frequency and 14 J/cm2, thickness of the resolidified material is in the range of 300 to 900 nm. The micro-Raman analysis revealed that the resolidified material contains amorphous calcium phosphate, while grazing incidence x-ray diffraction analysis allowed detecting traces of a calcium phosphate other than hydroxyapatite, probably β-tricalcium phosphate Ca3), at the surface of this specimen. The present results show that the ablation of enamel involves melting of enamel's hydroxyapatite, but the thickness of the altered layer is very small and thermal damage of the remaining material is negligible.

  4. Pellet ablation and ablation model development

    International Nuclear Information System (INIS)

    Houlberg, W.A.

    1989-01-01

    A broad survey of pellet ablation is given, based primarily on information presented at this meeting. The implications of various experimental observations for ablation theory are derived from qualitative arguments of the physics involved. The major elements of a more complete ablation theory are then outlined in terms of these observations. This is followed by a few suggestions on improving the connections between theory and experimental results through examination of ablation data. Although this is a rather aggressive undertaking for such a brief (and undoubtedly incomplete) assessment, some of the discussion may help us advance the understanding of pellet ablation. 17 refs

  5. Combined treatment of tyrosine kinase inhibitor labeled gold nanorod encapsulated albumin with laser thermal ablation in a renal cell carcinoma model

    Science.gov (United States)

    This manuscript served to characterize and evaluate Human Serum Albumin-encapsulated Nanoparticles (NPs) for drug delivery of a tyrosine kinase inhibitor combined with induction of photothermal ablation (PTA) combination therapy of Renal Cell Carcinoma (RCC). RCC is the most common type of kidney c...

  6. Osteoid Osteoma: Experience with Laser- and Radiofrequency-Induced Ablation

    International Nuclear Information System (INIS)

    Gebauer, Bernhard; Tunn, Per-Ulf; Gaffke, Gunnar; Melcher, Ingo; Felix, Roland; Stroszczynski, Christian

    2006-01-01

    The purpose of this study was to analyze the clinical outcome of osteoid osteoma treated by thermal ablation after drill opening. A total of 17 patients and 20 procedures were included. All patients had typical clinical features (age, pain) and a typical radiograph showing a nidus. In 5 cases, additional histological specimens were acquired. After drill opening of the osteoid osteoma nidus, 12 thermal ablations were induced by laser interstitial thermal therapy (LITT) (9F Power-Laser-Set; Somatex, Germany) and 8 ablations by radiofrequency ablation (RFA) (RITA; StarBurst, USA). Initial clinical success with pain relief has been achieved in all patients after the first ablation. Three patients had an osteoid osteoma recurrence after 3, 9, and 10 months and were successfully re-treated by thermal ablation. No major complication and one minor complication (sensible defect) were recorded. Thermal ablation is a safe and minimally invasive therapy option for osteoid osteoma. Although the groups are too small for a comparative analysis, we determined no difference between laser- and radiofrequency-induced ablation in clinical outcome after ablation

  7. Thermal therapy for breast tumors by using a cylindrical ultrasound phased array with multifocus pattern scanning: a preliminary numerical study

    International Nuclear Information System (INIS)

    Ho, C-S; Ju, K-C; Cheng, T-Y; Chen, Y-Y; Lin, W-L

    2007-01-01

    The purpose of this study is to investigate the feasibility of using a 1 MHz cylindrical ultrasound phased array with multifocus pattern scanning to produce uniform heating for breast tumor thermal therapy. The breast was submerged in water and surrounded by the cylindrical ultrasound phased array. A multifocus pattern was generated and electrically scanned by the phased array to enlarge the treatment lesion in single heating. To prevent overheating normal tissues, a large planning target volume (PTV) would be divided into several planes with several subunits on each plane and sequentially treated with a cooling phase between two successive heatings of the subunit. Heating results for different target temperatures (T tgt ), blood perfusion rates and sizes of the PTV have been studied. Furthermore, a superficial breast tumor with different water temperatures was also studied. Results indicated that a higher target temperature would produce a slightly larger thermal lesion, and a higher blood perfusion rate would not affect the heating lesion size but increase the heating time significantly. The acoustic power deposition and temperature elevations in ribs can be minimized by orienting the acoustic beam from the ultrasound phased array approximately parallel to the ribs. In addition, a large acoustic window on the convex-shaped breast surface for the proposed ultrasound phased array and the cooling effect of water would prevent the skin overheating for the production of a lesion at any desired location. This study demonstrated that the proposed cylindrical ultrasound phased array can provide effective heating for breast tumor thermal therapy without overheating the skin and ribs within a reasonable treatment time

  8. Clinical application and developmental trend of radiofrequency ablation technology

    International Nuclear Information System (INIS)

    Chen Dongfeng

    2009-01-01

    For recent two decades, radiofrequency ablation technology has made great progress in the field of the treatment for neoplasm. At the very beginning, radiofrequency ablation was adopted in treating the hepatic carcinoma, and since then it has been gradually practiced in treating malignancies of lung, bone, kidney, breast, prostate and other solid tumors. Statistical report of the year 2008 has indicated that in the aspect of similar therapeutic measures radiofrequency ablation therapy for tumors holds a 9% market share. Moreover, in the coming years the clinical use of this kind of therapy for tumors will be steadily increasing by 13% every year. (authors)

  9. Percutaneous Microwave Ablation of Renal Angiomyolipomas

    Energy Technology Data Exchange (ETDEWEB)

    Cristescu, Mircea, E-mail: mcristescu@uwhealth.org [University of Wisconsin, Department of Radiology (United States); Abel, E. Jason, E-mail: abel@urology.wisc.edu [University of Wisconsin, Department of Urology (United States); Wells, Shane, E-mail: swells@uwhealth.org; Ziemlewicz, Timothy J., E-mail: tziemlewicz@uwhealth.org [University of Wisconsin, Department of Radiology (United States); Hedican, Sean P., E-mail: hedican@surgery.wisc.edu [University of Wisconsin, Department of Urology (United States); Lubner, Megan G., E-mail: mlubner@uwhealth.org; Hinshaw, J. Louis, E-mail: jhinshaw@uwhealth.org; Brace, Christopher L., E-mail: cbrace@uwhealth.org; Lee, Fred T., E-mail: flee@uwhealth.org [University of Wisconsin, Department of Radiology (United States)

    2016-03-15

    PurposeTo evaluate the safety and efficacy of US-guided percutaneous microwave (MW) ablation in the treatment of renal angiomyolipoma (AML).Materials and MethodsFrom January 2011 to April 2014, seven patients (5 females and 2 males; mean age 51.4) with 11 renal AMLs (9 sporadic type and 2 tuberous sclerosis associated) with a mean size of 3.4 ± 0.7 cm (range 2.4–4.9 cm) were treated with high-powered, gas-cooled percutaneous MW ablation under US guidance. Tumoral diameter, volume, and CT/MR enhancement were measured on pre-treatment, immediate post-ablation, and delayed post-ablation imaging. Clinical symptoms and creatinine were assessed on follow-up visits.ResultsAll ablations were technically successful and no major complications were encountered. Mean ablation parameters were ablation power of 65 W (range 60–70 W), using 456 mL of hydrodissection fluid per patient, over 4.7 min (range 3–8 min). Immediate post-ablation imaging demonstrated mean tumor diameter and volume decreases of 1.8 % (3.4–3.3 cm) and 1.7 % (27.5–26.3 cm{sup 3}), respectively. Delayed imaging follow-up obtained at a mean interval of 23.1 months (median 17.6; range 9–47) demonstrated mean tumor diameter and volume decreases of 29 % (3.4–2.4 cm) and 47 % (27.5–12.1 cm{sup 3}), respectively. Tumoral enhancement decreased on immediate post-procedure and delayed imaging by CT/MR parameters, indicating decreased tumor vascularity. No patients required additional intervention and no patients experienced spontaneous bleeding post-ablation.ConclusionOur early experience with high-powered, gas-cooled percutaneous MW ablation demonstrates it to be a safe and effective modality to devascularize and decrease the size of renal AMLs.

  10. Enhancement of Intermittent Androgen Ablation Therapy by Finasteride Administration in Animal Models

    National Research Council Canada - National Science Library

    Wang, Zhou

    2006-01-01

    .... Intermittent androgen ablation therapy (IAAT) may slow down the development of androgen refractory tumors because intermittent recovery of androgens can induce differentiation of prostatic epithelial cells...

  11. Enhancement of Intermittent Androgen Ablation Therapy by Finasteride Administration in Animal Models

    National Research Council Canada - National Science Library

    Wang, Zhou

    2004-01-01

    .... Intermittent androgen ablation therapy may slow down the development of androgen refractory tumors because intermittent recovery of androgens can induce differentiation of prostatic epithelial cells...

  12. Enhancement of Intermittent Androgen Ablation Therapy by Finasteride Administration in Animal Models

    National Research Council Canada - National Science Library

    Wang, Zhou

    2005-01-01

    .... Intermittent androgen ablation therapy may slow down the development of androgen refractory tumors because intermittent recovery of androgens can induce differentiation of prostatic epithelial cells...

  13. Enhancement of Intermittent Androgen Ablation Therapy by Finasteride Administration in Animal Models

    National Research Council Canada - National Science Library

    Wang, Zhou

    2003-01-01

    .... Intermittent androgen ablation therapy may slow down the development of androgen refractory tumors because intermittent recovery of androgens can induce differentiation of prostatic epithelial cells...

  14. Targeting doxorubicin encapsulated in stealth liposomes to solid tumors by non thermal diode laser.

    Science.gov (United States)

    Ghannam, Magdy M; El Gebaly, Reem; Fadel, Maha

    2016-04-05

    The use of liposomes as drug delivery systems is the most promising technique for targeting drug especially for anticancer therapy. In this study sterically stabilized liposomes was prepared from DPPC/Cholesterol/PEG-PE encapsulated doxorubicin. The effect of lyophilization on liposomal stability and hence expiration date were studied. Moreover, the effect of diode laser on the drug released from liposomesin vitro and in vivo in mice carrying implanted solid tumor were also studied. The results indicated that lyophilization of the prepared liposomes encapsulating doxorubicin led to marked stability when stored at 5 °C and it is possible to use the re-hydrated lyophilized liposomes within 12 days post reconstitution. Moreover, the use of low energy diode laser for targeting anticancer drug to the tumor cells is a promising method in cancer therapy. We can conclude that lyophilization of the liposomes encapsulating doxorubicin lead to marked stability for the liposomes when stored at 5 °C. Moreover, the use of low energy diode laser for targeting anticancer drug to the tumor cells through the use of photosensitive sterically stabilized liposomes loaded with doxorubicin is a promising method. It proved to be applicable and successful for treatment of Ehrlich solid tumors implanted in mice and eliminated toxic side effects of doxorubicin.

  15. Avoiding Complications in Bone and Soft Tissue Ablation

    International Nuclear Information System (INIS)

    Kurup, A. Nicholas; Schmit, Grant D.; Morris, Jonathan M.; Atwell, Thomas D.; Schmitz, John J.; Weisbrod, Adam J.; Woodrum, David A.; Eiken, Patrick W.; Callstrom, Matthew R.

    2017-01-01

    As with percutaneous ablation of tumors in the liver, lungs, and kidneys, ablation of bone and non-visceral soft tissue tumors carries risk, primarily from collateral damage to vital structures in proximity to the target tumor. Certain risks are of particular interest when ablating bone and non-visceral soft tissue tumors, namely neural or skin injury, bowel injury, fracture, and gas embolism from damaged applicators. Ablation of large volume tumors also carries special risk. Many techniques may be employed by the interventional radiologist to minimize complications when treating tumors in the musculoskeletal system. These methods include those to depict, displace, or monitor critical structures. Thus, measures to provide thermoprotection may be active, such as careful ablation applicator placement and use of various displacement techniques, as well as passive, including employment of direct temperature, radiographic, or neurophysiologic monitoring techniques. Cementoplasty should be considered in certain skeletal locations at risk of fracture. Patients treated with large volume tumors should be monitored for renal dysfunction and properly hydrated. Finally, ablation applicators should be cautiously placed in the constrained environment of intact bone.

  16. Avoiding Complications in Bone and Soft Tissue Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Kurup, A. Nicholas, E-mail: kurup.anil@mayo.edu; Schmit, Grant D., E-mail: schmit.grant@mayo.edu; Morris, Jonathan M., E-mail: morris.jonathan@mayo.edu; Atwell, Thomas D., E-mail: atwell.thomas@mayo.edu; Schmitz, John J., E-mail: schmitz.john@mayo.edu; Weisbrod, Adam J., E-mail: weisbrod.adam@mayo.edu; Woodrum, David A., E-mail: woodrum.david@mayo.edu; Eiken, Patrick W., E-mail: eiken.patrick@mayo.edu; Callstrom, Matthew R., E-mail: callstrom.matthew@mayo.edu [Mayo Clinic, Department of Radiology (United States)

    2017-02-15

    As with percutaneous ablation of tumors in the liver, lungs, and kidneys, ablation of bone and non-visceral soft tissue tumors carries risk, primarily from collateral damage to vital structures in proximity to the target tumor. Certain risks are of particular interest when ablating bone and non-visceral soft tissue tumors, namely neural or skin injury, bowel injury, fracture, and gas embolism from damaged applicators. Ablation of large volume tumors also carries special risk. Many techniques may be employed by the interventional radiologist to minimize complications when treating tumors in the musculoskeletal system. These methods include those to depict, displace, or monitor critical structures. Thus, measures to provide thermoprotection may be active, such as careful ablation applicator placement and use of various displacement techniques, as well as passive, including employment of direct temperature, radiographic, or neurophysiologic monitoring techniques. Cementoplasty should be considered in certain skeletal locations at risk of fracture. Patients treated with large volume tumors should be monitored for renal dysfunction and properly hydrated. Finally, ablation applicators should be cautiously placed in the constrained environment of intact bone.

  17. Radiofrequency ablation for hepatocellular carcinoma: assistant techniques for difficult cases.

    Science.gov (United States)

    Inoue, Tatsuo; Minami, Yasunori; Chung, Hobyung; Hayaishi, Sousuke; Ueda, Taisuke; Tatsumi, Chie; Takita, Masahiro; Kitai, Satoshi; Hatanaka, Kinuyo; Ishikawa, Emi; Yada, Norihisa; Hagiwara, Satoru; Ueshima, Kazuomi; Kudo, Masatoshi

    2010-07-01

    To confirm the safety and effectiveness of techniques to assist radiofrequency ablation (RFA) for difficult cases, we retrospectively evaluated successful treatment rates, early complications and local tumor progressions. Between June 1999 and April 2009, a total of 341 patients with 535 nodules were treated as difficult cases. Artificial pleural effusion assisted ablation was performed on 64 patients with 82 nodules. Artificial ascites-assisted ablation was performed on 11 patients with 13 nodules. Cooling by endoscopic nasobiliary drainage (ENBD) tube-assisted ablation was performed on 6 patients with 8 nodules. When the tumors were not well visualized with conventional B-mode ultrasonography (US), contrast-enhanced US-assisted ablation with Levovist or Sonazoid or virtual CT sonography-assisted ablation was performed. Contrast-enhanced US-assisted ablation was performed on 139 patients with 224 nodules and virtual CT sonography-assisted ablation was performed on 121 patients with 209 nodules. In total, complete ablation was achieved in 514 of 535 (96%) nodules in difficult cases. For RFA with artificial pleural effusion, artificial ascites and ENBD, complete response was confirmed in all cases. For contrast-enhanced US- and CT sonography-assisted ablation, complete response was 95%. Early complications were recognized in 24 cases (4.5%). All cases recovered with no invasive treatment. Local tumor recurrence was investigated in 377 nodules of 245 patients, and 69 (18%) nodules were positive. Tumor recurrences in each assisted technique were 14.7% in artificial pleural effusion cases, 7% in artificial ascites, 12.5% in ENBD tube cases, 31% in virtual CT sonography, and 8.5% in contrast-enhanced US. Although local tumor progression needs to be carefully monitored, assisted techniques of RFA for difficult cases are well tolerated and expand the indications of RFA. Copyright (c) 2010 S. Karger AG, Basel.

  18. Percutaneous Irreversible Electroporation of Unresectable Hilar Cholangiocarcinoma (Klatskin Tumor): A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Melenhorst, Marleen C. A. M., E-mail: m.melenhorst@vumc.nl; Scheffer, Hester J., E-mail: hj.scheffer@vumc.nl; Vroomen, Laurien G. P. H., E-mail: la.vroomen@vumc.nl [VU University Medical Center, Department of Radiology and Nuclear Medicine (Netherlands); Kazemier, Geert, E-mail: g.kazemier@vumc.nl; Tol, M. Petrousjka van den, E-mail: mp.vandentol@vumc.nl [VU University Medical Center, Department of Surgery (Netherlands); Meijerink, Martijn R., E-mail: mr.meijerink@vumc.nl [VU University Medical Center, Department of Radiology and Nuclear Medicine (Netherlands)

    2016-01-15

    Irreversible electroporation (IRE) is a novel image-guided ablation technique that is rapidly gaining popularity in the treatment of malignant tumors located near large vessels or bile ducts. The presence of metal objects in the ablation zone, such as Wallstents, is generally considered a contraindication for IRE, because tissue heating due to power conduction may lead to thermal complications. This report describes a 66-year-old female with a Bismuth–Corlette stage IV unresectable cholangiocarcinoma with a metallic Wallstent in the common bile duct, who was safely treated with percutaneous IRE with no signs for relapse 1 year after the procedure.

  19. Significance of performing CT after radiofrequency ablation of hepatocellular carcinoma. Relationship between CT findings in areas other than the tumor site and post therapeutic outcome

    International Nuclear Information System (INIS)

    Shimokoube, Kouichi; Saito, Kazuhiro; Kotake, Fumio; Nakamura, Hiroshi; Mizokami, Yuji; Mikami, Ryuji; Matsuoka, Takeshi

    2004-01-01

    The relationships between the CT findings following radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) and the clinical symptoms and laboratory data were examined. The subjects consisted of 31 cases (41 nodules) of HCC that were treated by RFA. The CT findings before and after RFA, particularly the findings in areas other than the treatment site (henceforth, secondary findings), were evaluated by a physician and a radiologist. In addition, the relationships between the CT findings and post-RFA clinical symptoms (fever/pain) and laboratory data were examined. Secondary findings were found in 90.3% (28/31). These findings were broadly classified into changes in the needle tract 51.6% (16/31), retention of effusion 41.9% (13/31), thickening of the gallbladder wall 12.9% (4/31), changes in the retroperitoneal space 9.7% (3/31), and dilatation of the intrahepatic bile duct 3.2% (1/31), in the order of frequency. A relationship was found between changes in the retroperitoneal space and the clinical symptoms (fever: p=0.0366, pain: p=0.0012). Relationships were also found between changes in the needle tract and retention of effusion and aspartate aminotransferase (AST) (p<0.0001), as well as between changes in the needle tract and alanine aminotransferase (ALT) (p=0.0149). The size of the treatment area did not correlate with the presence of clinical symptoms and changes in laboratory data. Diverse classification of CT findings was observed after RFA, and a relationship with clinical symptoms was noted. A relationship was also found between classification of the CT findings following RFA and the post-therapeutic outcome. (authors)

  20. Radioiodine Remnant Ablation: A Critical Review

    International Nuclear Information System (INIS)

    Bal, Chandra Sekhar; Padhy, Ajit Kumar

    2015-01-01

    Radioiodine remnant ablation (RRA) is considered a safe and effective method for eliminating residual thyroid tissue, as well as microscopic disease if at all present in thyroid bed following thyroidectomy. The rationale of RRA is that in the absence of thyroid tissue, serum thyroglobulin (Tg) measurement can be used as an excellent tumor marker. Other considerations are like the presence of significant remnant thyroid tissue makes detection and treatment of nodal or distant metastases difficult. Rarely, microscopic disease in the thyroid bed if not ablated, in the future, could be a source of anaplastic transformation. On the other hand, microscopic tumor emboli in distant sites could be the cause of distant metastasis too. The ablation of remnant tissue would in all probability eliminate these theoretical risks. It may be noted that all these are unproven contentious issues except postablation serum Tg estimation that could be a good tumor marker for detecting early biochemical recurrence in long-term follow-up strategy. Radioactive iodine is administered as a form of “adjuvant therapy” for remnant ablation. There have been several reports with regard to the administered dose for remnant ablation. The first report of a prospective randomized clinical trial was published from India by a prospective randomized study conducted at the All India Institute of Medical Sciences, New Delhi in the year 1996. The study reported that increasing the empirical 131 I initial dose to more than 50 mCi results in plateauing of the dose-response curve and thus, conventional high-dose remnant ablation needs critical evaluation. Recently, two important studies were published: One from French group and the other from UK on a similar line. Interestingly, all three studies conducted in three different geographical regions of the world showed exactly similar conclusion. The new era of low-dose remnant ablation has taken a firm scientific footing across the continents

  1. Prostate-specific membrane antigen-directed nanoparticle targeting for extreme nearfield ablation of prostate cancer cells.

    Science.gov (United States)

    Lee, Seung S; Roche, Philip Jr; Giannopoulos, Paresa N; Mitmaker, Elliot J; Tamilia, Michael; Paliouras, Miltiadis; Trifiro, Mark A

    2017-03-01

    Almost all biological therapeutic interventions cannot overcome neoplastic heterogeneity. Physical ablation therapy is immune to tumor heterogeneity, but nearby tissue damage is the limiting factor in delivering lethal doses. Multi-walled carbon nanotubes offer a number of unique properties: chemical stability, photonic properties including efficient light absorption, thermal conductivity, and extensive surface area availability for covalent chemical ligation. When combined together with a targeting moiety such as an antibody or small molecule, one can deliver highly localized temperature increases and cause extensive cellular damage. We have functionalized multi-walled carbon nanotubes by conjugating an antibody against prostate-specific membrane antigen. In our in vitro studies using prostate-specific membrane antigen-positive LNCaP prostate cancer cells, we have effectively demonstrated cell ablation of >80% with a single 30-s exposure to a 2.7-W, 532-nm laser for the first time without bulk heating. We also confirmed the specificity and selectivity of prostate-specific membrane antigen targeting by assessing prostate-specific membrane antigen-null PC3 cell lines under the same conditions (<10% cell ablation). This suggests that we can achieve an extreme nearfield cell ablation effect, thus restricting potential tissue damage when transferred to in vivo clinical applications. Developing this new platform will introduce novel approaches toward current therapeutic modalities and will usher in a new age of effective cancer treatment squarely addressing tumoral heterogeneity.

  2. Paying attention to radiofrequency ablation therapy for neoplasms

    International Nuclear Information System (INIS)

    Wang Zhongming; Li Linsun

    2010-01-01

    Radiofrequency ablation is an effective treatment for malignant tumors. With the development of imaging technique, it has been widely used in treating different kinds of malignant tumors, such as liver cancer, lung cancer, kidney carcinoma, etc. Radiofrequency ablation has a lot of advantages. As a minimally-invasive, safe and effective treatment with less sufferings and fewer complications, this technique has attracted more and more attention of the experts both at home and abroad. (authors)

  3. CMCTS stabilized Fe3O4 particles with extremely low toxicity as highly efficient near-infrared photothermal agents for in vivo tumor ablation

    Science.gov (United States)

    Shen, Song; Kong, Fenfen; Guo, Xiaomeng; Wu, Lin; Shen, Haijun; Xie, Meng; Wang, Xinshi; Jin, Yi; Ge, Yanru

    2013-08-01

    With the potential uses of photothermal therapy (PTT) in cancer treatment with excellent efficacy, and the growing concerns about the nanotoxicity of hyperthermia agents such as carbon nanotubes and gold-based nanomaterials, the importance of searching for a biocompatible hyperthermia agent cannot be emphasized too much. In this work, a novel promising hyperthermia agent employing magnetic Fe3O4 particles with fairly low toxicity was proposed. This hyperthermia agent showed rapid heat generation under NIR irradiation. After modification with carboxymethyl chitosan (CMCTS), the obtained Fe3O4@CMCTS particles could disperse stably in PBS and serum without any aggregation. The modification of CMCTS could decrease the adsorption of bovine serum albumin (BSA) and improve the cellular uptake. In a comparative study with hollow gold nanospheres (HAuNS), Fe3O4@CMCTS particles exhibited a comparable photothermal effect and fairly low cytotoxicity. The in vivo magnetic resonance (MR) images of mice revealed that by attaching a magnet to the tumor, Fe3O4@CMCTS particles accumulated in the tumor after intravenous injection and showed a low distribution in the liver. After being exposed to a 808 nm laser for 5 min at a low power density of 1.5 W cm-2, the tumors on Fe3O4@CMCTS-injected mice reached a temperature of ~52 °C and were completely destroyed. Thus, a kind of multifunctional magnetic nanoparticle with extremely low toxicity and a simple structure for simultaneous MR imaging, targeted drug delivery and photothermal therapy can be easily fabricated.With the potential uses of photothermal therapy (PTT) in cancer treatment with excellent efficacy, and the growing concerns about the nanotoxicity of hyperthermia agents such as carbon nanotubes and gold-based nanomaterials, the importance of searching for a biocompatible hyperthermia agent cannot be emphasized too much. In this work, a novel promising hyperthermia agent employing magnetic Fe3O4 particles with fairly low

  4. Radiofrequency ablation of two femoral head chondroblastomas

    Energy Technology Data Exchange (ETDEWEB)

    Petsas, Theodore [Department of Radiology, University of Patras (Greece); Megas, Panagiotis [Department of Orthopaedic Surgery, University of Patras (Greece)]. E-mail: panmegas@med.upatras.gr; Papathanassiou, Zafiria [Department of Radiology, University of Patras (Greece)

    2007-07-15

    Chondroblastoma is a rare benign cartilaginous bone tumor. Surgical resection is the treatment of choice for pain relief and prevention of further growth. Open surgical techniques are associated with complications, particularly when the tumors are located in deep anatomical sites. The authors performed RF ablation in two cases of subarticular femoral head chondroblastomas and emphasize its positive impact. The clinical course, the radiological findings and the post treatment results are discussed.

  5. Fracture in Phenolic Impregnated Carbon Ablator

    Science.gov (United States)

    Agrawal, Parul; Chavez-Garcia, Jose; Pham, John

    2013-01-01

    This paper describes the development of a novel technique to understand the failure mechanisms inside thermal protection materials. The focus of this research is on the class of materials known as phenolic impregnated carbon ablators. It has successfully flown on the Stardust spacecraft and is the thermal protection system material chosen for the Mars Science Laboratory and SpaceX Dragon spacecraft. Although it has good thermal properties, structurally, it is a weak material. To understand failure mechanisms in carbon ablators, fracture tests were performed on FiberForm(Registered TradeMark) (precursor), virgin, and charred ablator materials. Several samples of these materials were tested to investigate failure mechanisms at a microstructural scale. Stress-strain data were obtained simultaneously to estimate the tensile strength and toughness. It was observed that cracks initiated and grew in the FiberForm when a critical stress limit was reached such that the carbon fibers separated from the binder. However, both for virgin and charred carbon ablators, crack initiation and growth occurred in the matrix (phenolic) phase. Both virgin and charred carbon ablators showed greater strength values compared with FiberForm samples, confirming that the presence of the porous matrix helps in absorbing the fracture energy.

  6. Radiofrequency ablation of hepatocellular carcinoma: Mono or multipolar?

    Science.gov (United States)

    Cartier, Victoire; Boursier, Jérôme; Lebigot, Jérôme; Oberti, Frédéric; Fouchard-Hubert, Isabelle; Aubé, Christophe

    2016-03-01

    Thermo-ablation by radiofrequency is recognized as a curative treatment for early-stage hepatocellular carcinoma. However, local recurrence may occur because of incomplete peripheral tumor destruction. Multipolar radiofrequency has been developed to increase the size of the maximal ablation zone. We aimed to compare the efficacy of monopolar and multipolar radiofrequency for the treatment of hepatocellular carcinoma and determine factors predicting failure. A total of 171 consecutive patients with 214 hepatocellular carcinomas were retrospectively included. One hundred fifty-eight tumors were treated with an expandable monopolar electrode and 56 with a multipolar technique using several linear bipolar electrodes. Imaging studies at 6 weeks after treatment, then every 3 months, assessed local effectiveness. Radiofrequency failure was defined as persistent residual tumor after two sessions (primary radiofrequency failure) or local tumor recurrence during follow-up. This study received institutional review board approval (number 2014/77). Imaging showed complete tumor ablation in 207 of 214 lesions after the first session of radiofrequency. After a second session, only two cases of residual viable tumor were observed. During follow-up, there were 46 local tumor recurrences. Thus, radiofrequency failure occurred in 48/214 (22.4%) cases. By multivariate analysis, technique (P radiofrequency failure. Failure rate was lower with the multipolar technique for tumors radiofrequency, multipolar radiofrequency improves tumor ablation with a subsequent lower rate of local tumor recurrence. © 2015 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

  7. Outcome after Radiofrequency Ablation of Sarcoma Lung Metastases

    Energy Technology Data Exchange (ETDEWEB)

    Koelblinger, Claus, E-mail: claus.koelblinger@bhs.at [KH Barmherzige Schwestern Ried, Department of Radiology (Austria); Strauss, Sandra, E-mail: s.strauss@ucl.ac.uk [UCL and UCLH, Department of Medical Oncology (United Kingdom); Gillams, Alice, E-mail: alliesorting@gmail.com [The London Clinic, Department of Radiology (United Kingdom)

    2013-05-14

    PurposeResection is the mainstay of management in patients with sarcoma lung metastases, but there is a limit to how many resections can be performed. Some patients with inoperable disease have small-volume lung metastases that are amenable to thermal ablation. We report our results after radiofrequency ablation (RFA).MethodsThis is a retrospective study of patients treated from 2007 to 2012 in whom the intention was to treat all sites of disease and who had a minimum CT follow-up of 4 months. Treatment was performed under general anesthesia/conscious sedation using cool-tip RFA. Follow-up CT scans were analyzed for local control. Primary tumor type, location, grade, disease-free interval, prior resection/chemotherapy, number and size of lung tumors, uni- or bilateral disease, complications, and overall and progression-free survival were recorded.ResultsTwenty-two patients [15 women; median age 48 (range 10–78) years] with 55 lung metastases were treated in 30 sessions. Mean and median tumor size and initial number were 0.9 cm and 0.7 (range 0.5–2) cm, and 2.5 and 1 (1–7) respectively. Median CT and clinical follow-up were 12 (4–54) and 20 (8–63) months, respectively. Primary local control rate was 52 of 55 (95 %). There were 2 of 30 (6.6 %) Common Terminology Criteria grade 3 complications with no long-term sequelae. Mean (median not reached) and 2- and 3-year overall survival were 51 months, and 94 and 85 %. Median and 1- and 2-year progression-free survival were 12 months, and 53 and 23 %. Prior disease-free interval was the only significant factor to affect overall survival.ConclusionRFA is a safe and effective treatment for patients with small-volume sarcoma metastases.

  8. Outcome after Radiofrequency Ablation of Sarcoma Lung Metastases

    International Nuclear Information System (INIS)

    Koelblinger, Claus; Strauss, Sandra; Gillams, Alice

    2014-01-01

    PurposeResection is the mainstay of management in patients with sarcoma lung metastases, but there is a limit to how many resections can be performed. Some patients with inoperable disease have small-volume lung metastases that are amenable to thermal ablation. We report our results after radiofrequency ablation (RFA).MethodsThis is a retrospective study of patients treated from 2007 to 2012 in whom the intention was to treat all sites of disease and who had a minimum CT follow-up of 4 months. Treatment was performed under general anesthesia/conscious sedation using cool-tip RFA. Follow-up CT scans were analyzed for local control. Primary tumor type, location, grade, disease-free interval, prior resection/chemotherapy, number and size of lung tumors, uni- or bilateral disease, complications, and overall and progression-free survival were recorded.ResultsTwenty-two patients [15 women; median age 48 (range 10–78) years] with 55 lung metastases were treated in 30 sessions. Mean and median tumor size and initial number were 0.9 cm and 0.7 (range 0.5–2) cm, and 2.5 and 1 (1–7) respectively. Median CT and clinical follow-up were 12 (4–54) and 20 (8–63) months, respectively. Primary local control rate was 52 of 55 (95 %). There were 2 of 30 (6.6 %) Common Terminology Criteria grade 3 complications with no long-term sequelae. Mean (median not reached) and 2- and 3-year overall survival were 51 months, and 94 and 85 %. Median and 1- and 2-year progression-free survival were 12 months, and 53 and 23 %. Prior disease-free interval was the only significant factor to affect overall survival.ConclusionRFA is a safe and effective treatment for patients with small-volume sarcoma metastases

  9. Image-Guided Spinal Ablation: A Review

    Energy Technology Data Exchange (ETDEWEB)

    Tsoumakidou, Georgia, E-mail: gtsoumakidou@yahoo.com; Koch, Guillaume, E-mail: guillaume.koch@chru-strasbourg.fr; Caudrelier, Jean, E-mail: jean.caudrelier@chru-strasbourg.fr; Garnon, Julien, E-mail: julien.garnon@chru-strasbourg.fr; Cazzato, Roberto Luigi, E-mail: roberto-luigi.cazzato@chru-strasbourg.fr; Edalat, Faramarz, E-mail: faramarz.edalat@gmail.com; Gangi, Afshin, E-mail: gangi@unistra.fr [Strasbourg University Hospital (France)

    2016-09-15

    The image-guided thermal ablation procedures can be used to treat a variety of benign and malignant spinal tumours. Small size osteoid osteoma can be treated with laser or radiofrequency. Larger tumours (osteoblastoma, aneurysmal bone cyst and metastasis) can be addressed with radiofrequency or cryoablation. Results on the literature of spinal microwave ablation are scarce, and thus it should be used with caution. A distinct advantage of cryoablation is the ability to monitor the ice-ball by intermittent CT or MRI. The different thermal insulation, temperature and electrophysiological monitoring techniques should be applied. Cautious pre-procedural planning and intermittent intra-procedural monitoring of the ablation zone can help reduce neural complications. Tumour histology, patient clinical-functional status and life-expectancy should define the most efficient and least disabling treatment option.

  10. Computational modeling of ultra-short-pulse ablation of enamel

    Energy Technology Data Exchange (ETDEWEB)

    London, R.A.; Bailey, D.S.; Young, D.A. [and others

    1996-02-29

    A computational model for the ablation of tooth enamel by ultra-short laser pulses is presented. The role of simulations using this model in designing and understanding laser drilling systems is discussed. Pulses of duration 300 sec and intensity greater than 10{sup 12} W/cm{sup 2} are considered. Laser absorption proceeds via multi-photon initiated plasma mechanism. The hydrodynamic response is calculated with a finite difference method, using an equation of state constructed from thermodynamic functions including electronic, ion motion, and chemical binding terms. Results for the ablation efficiency are presented. An analytic model describing the ablation threshold and ablation depth is presented. Thermal coupling to the remaining tissue and long-time thermal conduction are calculated. Simulation results are compared to experimental measurements of the ablation efficiency. Desired improvements in the model are presented.

  11. Enhanced Radiofrequency Ablation With Magnetically Directed Metallic Nanoparticles.

    Science.gov (United States)

    Nguyen, Duy T; Tzou, Wendy S; Zheng, Lijun; Barham, Waseem; Schuller, Joseph L; Shillinglaw, Benjamin; Quaife, Robert A; Sauer, William H

    2016-05-01

    Remote heating of metal located near a radiofrequency ablation source has been previously demonstrated. Therefore, ablation of cardiac tissue treated with metallic nanoparticles may improve local radiofrequency heating and lead to larger ablation lesions. We sought to evaluate the effect of magnetic nanoparticles on tissue sensitivity to radiofrequency energy. Ablation was performed using an ablation catheter positioned with 10 g of force over prepared ex vivo specimens. Tissue temperatures were measured and lesion volumes were acquired. An in vivo porcine thigh model was used to study systemically delivered magnetically guided iron oxide (FeO) nanoparticles during radiofrequency application. Magnetic resonance imaging and histological staining of ablated tissue were subsequently performed as a part of ablation lesion analysis. Ablation of ex vivo myocardial tissue treated with metallic nanoparticles resulted in significantly larger lesions with greater impedance changes and evidence of increased thermal conductivity within the tissue. Magnet-guided localization of FeO nanoparticles within porcine thigh preps was demonstrated by magnetic resonance imaging and iron staining. Irrigated ablation in the regions with greater FeO, after FeO infusion and magnetic guidance, created larger lesions without a greater incidence of steam pops. Metal nanoparticle infiltration resulted in significantly larger ablation lesions with altered electric and thermal conductivity. In vivo magnetic guidance of FeO nanoparticles allowed for facilitated radiofrequency ablation without direct infiltration into the targeted tissue. Further research is needed to assess the clinical applicability of this ablation strategy using metallic nanoparticles for the treatment of cardiac arrhythmias. © 2016 American Heart Association, Inc.

  12. Nanotechnology combined therapy: tyrosine kinase-bound gold nanorod and laser thermal ablation produce a synergistic higher treatment response of renal cell carcinoma in animal model

    Science.gov (United States)

    Immunologically naïve nude mice (Athymic Nude-Foxn1nu) were injected bilaterally on the flanks (n=36) with 2.5 x 106 cells of a human metastatic renal cell carcinoma cell line (RCC 786-O). Subcutaneous xenograft tumors developed 1 cm palpable nodules. AuNR encapsulated in Human Serum Albumin (HSA) P...

  13. CT-guided Bipolar and Multipolar Radiofrequency Ablation (RF Ablation) of Renal Cell Carcinoma: Specific Technical Aspects and Clinical Results

    International Nuclear Information System (INIS)

    Sommer, C. M.; Lemm, G.; Hohenstein, E.; Bellemann, N.; Stampfl, U.; Goezen, A. S.; Rassweiler, J.; Kauczor, H. U.; Radeleff, B. A.; Pereira, P. L.

    2013-01-01

    Purpose. This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. Methods. We included 22 consecutive patients (3 women; age 74.2 ± 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 ± 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. Results. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 ± 13.6 min and 43.7 ± 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 ± 8.8 months, local recurrence-free survival was 14.4 ± 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 ± 16.6 ml/min/1.73 m 2 before RF ablation vs. 47.2 ± 11.9 ml/min/1.73 m 2 after RF ablation; not significant). Conclusions. CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

  14. CT-guided Bipolar and Multipolar Radiofrequency Ablation (RF Ablation) of Renal Cell Carcinoma: Specific Technical Aspects and Clinical Results

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Lemm, G.; Hohenstein, E. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany); Bellemann, N.; Stampfl, U. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Goezen, A. S.; Rassweiler, J. [Clinic for Urology, SLK Kliniken Heilbronn GmbH (Germany); Kauczor, H. U.; Radeleff, B. A. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Pereira, P. L. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany)

    2013-06-15

    Purpose. This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. Methods. We included 22 consecutive patients (3 women; age 74.2 {+-} 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 {+-} 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. Results. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 {+-} 13.6 min and 43.7 {+-} 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 {+-} 8.8 months, local recurrence-free survival was 14.4 {+-} 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 {+-} 16.6 ml/min/1.73 m{sup 2} before RF ablation vs. 47.2 {+-} 11.9 ml/min/1.73 m{sup 2} after RF ablation; not significant). Conclusions. CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

  15. Infrared thermal measurements of laser soft tissue ablation as a function of air/water coolant for Nd:YAG and diode lasers

    Science.gov (United States)

    Gekelman, Diana; Yamamoto, Andrew; Oto, Marvin G.; White, Joel M.

    2003-06-01

    The purpose of this investigation was to measure the maximum temperature at the Nd:YAG and Diode lasers fiberoptic tips as a function of air/water coolant, during soft tissue ablation in pig jaws. A pulsed Nd:YAG laser (1064nm) and a Diode laser (800-830 nm) were used varying parameters of power, conditioning or not of the fiber tip, under 4 settings o