link
Bookmarks
Percutaneous Tumor Ablation
Nicolas Cardenas, MD; Jessica L. Burris, BS; Joshua Kuban, MD
To access 4,300 diagnoses written by the world's leading experts in radiology, please log in or subscribe.Subscribe

KEY FACTS

  • Terminology

    • Preprocedure

      • Procedure

        • Post Procedure

          • Outcomes

            TERMINOLOGY

            • Definitions

              • Lung cancer
                • Epidemiology
                  • 2nd most common cancer type in USA; leading cause of cancer-related death
                  • Estimated 228,820 new cases of lung cancer diagnosed in 2020 in USA
                  • Non-small cell lung cancer (NSCLC) is most common cancer subtype (80-85% of primary lung cancer)
                  • Lungs are 2nd most frequent site of metastatic disease [colorectal, renal cell carcinoma (RCC), breast, sarcomas, germ cell tumors]
                • TNM staging system
                  • Stage IA
                    • T1: 3 cm surrounded by lung/visceral pleura, not involving main bronchus, no nodal (N0) or metastatic spread (M0)
                    • T1a: ≤ 1 cm; T1b: > 1 cm to ≤ 2 cm; T1c: > 2 cm to ≤ 3 cm
              • Liver cancer
                • Epidemiology
                  • Hepatocellular carcinoma (HCC) is most common primary liver malignancy
                  • 6th most common newly diagnosed primary malignancy worldwide
                  • Colorectal cancer (CRC)
                    • 3rd most common newly diagnosed solid cancer worldwide
                    • Liver is most common site of metastasis
                    • Incidence: 38.9 new diagnoses/100,000 people in North America
                • Barcelona clinic liver cancer staging system (BCLC)
                  • Used to stratify patients to decide best treatment plan
                  • Consider following
                    • Number and size of hepatic tumors
                    • Patient performance status (PS) using Eastern Cooperative Oncology Group (ECOG) scale
                    • Child-Pugh system
                  • BCLC stages 0, A, B, C, D
                • Milan criteria
                  • Determines eligibility for liver transplantation
              • Kidney cancer
                • Epidemiology
                  • RCC is most common renal malignancy
                  • 12th most newly diagnosed primary malignancy worldwide
                  • Incidence: 15.9 new diagnoses/100,000 people in North America
                • TNM staging system
                  • T1: < 7 cm in greatest dimension, confined to kidney
                    • T1a: < 4 cm, T1b: > 4 cm and < 7 cm
              • Bone/soft tissue tumors
                • Epidemiology
                  • Osteoid osteomas are benign tumors that account for 10-12% of benign bone tumors
                    • Symptom onset between 5-24 years of age; male predominance
                  • Bone is 3rd most common site of metastasis
            • Ablation Modalities

              • Radiofrequency ablation (RFA)
                • Physics
                  • Transforms radiofrequency (RF) energy into heat
                  • RF generator ranging from 60-250 W produces alternating current, resulting in agitation of ions surrounding probe tip
                  • Ionic agitation leads to frictional heat, which is deposited within surrounding tissue/tumor
                  • Tissue temperature parameters
                    • Goal of 60-100 °C: Irreversible cellular damage occurs instantly at this temperature; goal temperature should be maintained for ~ 8-16 minutes, depending on RFA system used
                    • 50-60 °C: May induce coagulation necrosis in minutes
                    • < 50 °C does not reliably induce necrosis
                    • > 100 °C should be avoided as high temperatures lead to tissue char/vaporization resulting in gas production, which acts as insulator, impeding further heat diffusion within surrounding tumor
                  • Applicator design
                    • Probe diameter range: 14-17.5 Fr
                    • 3 types of RF applicators: Single straight needle, cluster straight needles, and multitoned expandable electrodes
                    • Main difference among applicators is size of ablation zones possible in one treatment
                    • Monopolar vs. bipolar RFA: Bipolar RFA allows for use of multiple probes simultaneously, creating larger ablation zones and making it less susceptible to heat sink
                  • Ablation zone
                    • Shape and size of ablation zone depends on both type and number of applicators placed within tumor
                    • Goal is 5- to 10-mm treatment margin beyond suspected tumor border
                • Advantages
                  • Intrinsic cautery effect may decrease bleeding complications
                • Disadvantages
                  • Associated with higher procedural pain than microwave ablation (MWA) or Cryo
                  • Variable tissue thermal conductivity may lead to irregular ablation margins
                  • Lung tissue has high impedance and low conduction, thus increasing procedure time
                  • Heat sink effect
                    • Flowing blood in nearby vessels cools tissue, limiting heating of tumor tissue
                    • Presence of vessels or bronchi > 3 mm in diameter within ablation zone may be predictor of incomplete local treatment due to "heat sink" effect
                  • May require slow and lengthy treatment to effectively kill tumor
              • MWA
                • Physics
                  • Relies on dielectric heating
                    • Applied electromagnetic field causes water molecules in surrounding tissues to rotate at microwave's frequency
                    • Rapidly oscillating water molecules results in frictional heating, raising tissue temperature surrounding probe tip
                    • Higher water content = better heat absorption and conductivity = larger ablation zone
                  • As with RFA, goal of treatment is to sustain temperatures > 50 °C and ideally > 60 °C
                  • Advantages
                    • More rapid generation of high temperatures
                    • Not limited by increased impedance seen with tissue boiling/charring in RFA: This allows for much higher intratumoral temperatures, leading to larger ablation zones with relatively shorter treatment durations
                    • Less susceptible to heat sink
                    • Does not require grounding pads
              • Cryoablation
                • Physics
                  • Causes tumor necrosis through rapid cell freezing
                    • Multifaceted cellular death: Protein denaturation, cell membrane rupture, vessel thrombosis/ischemia
                  • Joules-Thomson effect
                    • Rapid expansion of argon gas at applicator tip leads to rapid drop in temperature (Joules-Thomson effect), cooling surrounding tissue: Temperatures can range from -80 to -150 °C
                    • To induce thaw cycle, compressed helium is circulated within applicator; expansion of helium at tip leads to rapid increase in temperature
                  • Process consists of alternating freezing and thawing cycles
                    • Triple cycle is typically used in lung (3-minute freeze, 3-minute passive thaw, 7-minute freeze, 3-minute passive thaw, 10-minute freeze followed by variable active/passive thaw to raise temp to 22 °C
                    • Nonlung ablation typically consists of 2 freeze cycles of variable length, depending on "ice ball" growth (10-minute freeze followed by 8-minute thaw cycle common)
                  • Multiple probes can be used to treat large tumors
                • Advantages
                  • Decreased procedure associated pain
                  • Real-time visualization of treatment area
                    • "Ice ball" readily visible with CT/US/MR guidance
                  • Ablation zone can be modulated by probe placement and modulating freeze power and time of each probe to create shapes that ensure tumor and margin coverage
                  • Data suggests increased efficacy of cryoablation compared to RFA/MWA in treating renal tumors
                  • Prospective data suggests efficacy comparable to partial nephrectomy, which is standard of care
                • Disadvantages
                  • Longer ablation time than thermal-based techniques
                  • More expensive, as multiple probes may be required
                  • System requires gas availability and storage

            PREPROCEDURE

            • Indications

              • Contraindications

                • Preprocedure Imaging

                  • Getting Started

                    PROCEDURE

                    • Patient Position/Location

                      • Alternative Procedures/Therapies

                        • Baseline Imaging and Planning

                          • Probe Insertion/Positioning

                            • Ancillary Procedures

                              • Intraprocedural Monitoring of Patient and Treatment

                                • Completion Imaging and Recovery

                                  POST PROCEDURE

                                  • Follow-Up

                                    OUTCOMES

                                    • Complications

                                      • Expected Outcomes

                                        Selected References

                                        1. Genshaft SJ et al: Society of Interventional Radiology multidisciplinary position statement on percutaneous ablation of non-small cell lung cancer and metastatic disease to the lungs: endorsed by the Canadian Association for Interventional Radiology, the Cardiovascular and Interventional Radiological Society of Europe, and the Society of Interventional Oncology. J Vasc Interv Radiol. 32(8):1241.e1-12, 2021
                                        2. Genshaft SJ et al: Society of Interventional Radiology quality improvement standards on percutaneous ablation of non-small cell lung cancer and metastatic disease to the lungs. J Vasc Interv Radiol. 32(8):1242.e1-10, 2021
                                        3. Gunn AJ et al: Society of Interventional Radiology quality improvement standards on percutaneous ablation in renal cell carcinoma. J Vasc Interv Radiol. 31(2):195-201.e3, 2020
                                        4. Morris CS et al: Society of Interventional Radiology position statement on the role of percutaneous ablation in renal cell carcinoma: endorsed by the Canadian Association for Interventional Radiology and the Society of Interventional Oncology. J Vasc Interv Radiol. 31(2):189-94.e3, 2020
                                        5. Izzo F et al: Radiofrequency ablation and microwave ablation in liver tumors: an update. Oncologist. 24(10):e990-1005, 2019
                                        6. Tafti BA et al: Lung ablation: indications and techniques. Semin Intervent Radiol. 36(3):163-75, 2019
                                        7. Mouli SK et al: The role of percutaneous image-guided thermal ablation for the treatment of pulmonary malignancies. AJR Am J Roentgenol. 209(4):740-51, 2017
                                        8. Wallace AN et al: Percutaneous image-guided cryoablation of musculoskeletal metastases: pain palliation and local tumor control. J Vasc Interv Radiol. 27(12):1788-96, 2016
                                        9. Zhang F et al: Prognostic factors for long-term survival in patients with renal-cell carcinoma after radiofrequency ablation. J Endourol. 30(1):37-42, 2016
                                        10. Lee H et al: Hepatectomy vs radiofrequency ablation for colorectal liver metastasis: a propensity score analysis. World J Gastroenterol. 21(11):3300-7, 2015
                                        11. US Cancer Statistics Working Group. United States Cancer Statistics: 1999–2012 Incidence and Mortality Web-based Report. Atlanta: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention and National Cancer Institute. 2015. http://www.cdc.gov/uscs
                                        12. Ahmed M et al: Image-guided tumor ablation: standardization of terminology and reporting criteria--a 10-year update: supplement to the consensus document. J Vasc Interv Radiol. 25(11):1706-8, 2014
                                        13. Gunn AJ et al: Percutaneous ablation of the small renal mass-techniques and outcomes. Semin Intervent Radiol. 31(1):33-41, 2014
                                        14. Hiraki T et al: Radiofrequency ablation for early-stage nonsmall cell lung cancer. Biomed Res Int. 152087, 2014
                                        15. Kurup AN: Percutaneous ablation for small renal masses-complications. Semin Intervent Radiol. 31(1):42-9, 2014
                                        16. Ridge CA et al: Epidemiology and staging of renal cell carcinoma. Semin Intervent Radiol. 31(1):3-8, 2014
                                        17. Belfiore G et al: Patients' survival in lung malignancies treated by microwave ablation: our experience on 56 patients. Eur J Radiol. 82(1):177-81, 2013
                                        18. Cucchetti A et al: Systematic review of surgical resection vs radiofrequency ablation for hepatocellular carcinoma. World J Gastroenterol. 19(26):4106-18, 2013
                                        19. Howlader N et al: SEER cancer statistics review, 1975-2012. http://seer.cancer.gov/csr/1975_2012/
                                        20. Kashima M et al: Complications after 1000 lung radiofrequency ablation sessions in 420 patients: a single center's experiences. AJR Am J Roentgenol. 197(4):W576-80, 2011
                                        21. Vogl TJ et al: Microwave ablation therapy: clinical utility in treatment of pulmonary metastases. Radiology. 261(2):643-51, 2011
                                        22. Hong K et al: Radiofrequency ablation: mechanism of action and devices. J Vasc Interv Radiol. 21(8 Suppl):S179-86, 2010
                                        23. Brace CL: Radiofrequency and microwave ablation of the liver, lung, kidney, and bone: what are the differences? Curr Probl Diagn Radiol. 38(3):135-43, 2009
                                        24. Gervais DA et al: Society of Interventional Radiology position statement on percutaneous radiofrequency ablation for the treatment of liver tumors. J Vasc Interv Radiol. 20(7 Suppl):S342-7, 2009
                                        25. Lencioni R et al: Response to radiofrequency ablation of pulmonary tumours: a prospective, intention-to-treat, multicentre clinical trial (the RAPTURE study). Lancet Oncol. 9(7):621-8, 2008
                                        26. Hiraki T et al: Pneumothorax, pleural effusion, and chest tube placement after radiofrequency ablation of lung tumors: incidence and risk factors. Radiology. 241(1):275-83, 2006
                                        27. Goldberg SN et al: Image-guided tumor ablation: standardization of terminology and reporting criteria. Radiology. 235(3):728-39, 2005
                                        28. Solbiati L et al: Percutaneous radio-frequency ablation of hepatic metastases from colorectal cancer: long-term results in 117 patients. Radiology. 221(1):159-66, 2001
                                        Related Anatomy
                                        Loading...
                                        Related Differential Diagnoses
                                        Loading...
                                        References
                                        Tables

                                        Tables

                                        KEY FACTS

                                        • Terminology

                                          • Preprocedure

                                            • Procedure

                                              • Post Procedure

                                                • Outcomes

                                                  TERMINOLOGY

                                                  • Definitions

                                                    • Lung cancer
                                                      • Epidemiology
                                                        • 2nd most common cancer type in USA; leading cause of cancer-related death
                                                        • Estimated 228,820 new cases of lung cancer diagnosed in 2020 in USA
                                                        • Non-small cell lung cancer (NSCLC) is most common cancer subtype (80-85% of primary lung cancer)
                                                        • Lungs are 2nd most frequent site of metastatic disease [colorectal, renal cell carcinoma (RCC), breast, sarcomas, germ cell tumors]
                                                      • TNM staging system
                                                        • Stage IA
                                                          • T1: 3 cm surrounded by lung/visceral pleura, not involving main bronchus, no nodal (N0) or metastatic spread (M0)
                                                          • T1a: ≤ 1 cm; T1b: > 1 cm to ≤ 2 cm; T1c: > 2 cm to ≤ 3 cm
                                                    • Liver cancer
                                                      • Epidemiology
                                                        • Hepatocellular carcinoma (HCC) is most common primary liver malignancy
                                                        • 6th most common newly diagnosed primary malignancy worldwide
                                                        • Colorectal cancer (CRC)
                                                          • 3rd most common newly diagnosed solid cancer worldwide
                                                          • Liver is most common site of metastasis
                                                          • Incidence: 38.9 new diagnoses/100,000 people in North America
                                                      • Barcelona clinic liver cancer staging system (BCLC)
                                                        • Used to stratify patients to decide best treatment plan
                                                        • Consider following
                                                          • Number and size of hepatic tumors
                                                          • Patient performance status (PS) using Eastern Cooperative Oncology Group (ECOG) scale
                                                          • Child-Pugh system
                                                        • BCLC stages 0, A, B, C, D
                                                      • Milan criteria
                                                        • Determines eligibility for liver transplantation
                                                    • Kidney cancer
                                                      • Epidemiology
                                                        • RCC is most common renal malignancy
                                                        • 12th most newly diagnosed primary malignancy worldwide
                                                        • Incidence: 15.9 new diagnoses/100,000 people in North America
                                                      • TNM staging system
                                                        • T1: < 7 cm in greatest dimension, confined to kidney
                                                          • T1a: < 4 cm, T1b: > 4 cm and < 7 cm
                                                    • Bone/soft tissue tumors
                                                      • Epidemiology
                                                        • Osteoid osteomas are benign tumors that account for 10-12% of benign bone tumors
                                                          • Symptom onset between 5-24 years of age; male predominance
                                                        • Bone is 3rd most common site of metastasis
                                                  • Ablation Modalities

                                                    • Radiofrequency ablation (RFA)
                                                      • Physics
                                                        • Transforms radiofrequency (RF) energy into heat
                                                        • RF generator ranging from 60-250 W produces alternating current, resulting in agitation of ions surrounding probe tip
                                                        • Ionic agitation leads to frictional heat, which is deposited within surrounding tissue/tumor
                                                        • Tissue temperature parameters
                                                          • Goal of 60-100 °C: Irreversible cellular damage occurs instantly at this temperature; goal temperature should be maintained for ~ 8-16 minutes, depending on RFA system used
                                                          • 50-60 °C: May induce coagulation necrosis in minutes
                                                          • < 50 °C does not reliably induce necrosis
                                                          • > 100 °C should be avoided as high temperatures lead to tissue char/vaporization resulting in gas production, which acts as insulator, impeding further heat diffusion within surrounding tumor
                                                        • Applicator design
                                                          • Probe diameter range: 14-17.5 Fr
                                                          • 3 types of RF applicators: Single straight needle, cluster straight needles, and multitoned expandable electrodes
                                                          • Main difference among applicators is size of ablation zones possible in one treatment
                                                          • Monopolar vs. bipolar RFA: Bipolar RFA allows for use of multiple probes simultaneously, creating larger ablation zones and making it less susceptible to heat sink
                                                        • Ablation zone
                                                          • Shape and size of ablation zone depends on both type and number of applicators placed within tumor
                                                          • Goal is 5- to 10-mm treatment margin beyond suspected tumor border
                                                      • Advantages
                                                        • Intrinsic cautery effect may decrease bleeding complications
                                                      • Disadvantages
                                                        • Associated with higher procedural pain than microwave ablation (MWA) or Cryo
                                                        • Variable tissue thermal conductivity may lead to irregular ablation margins
                                                        • Lung tissue has high impedance and low conduction, thus increasing procedure time
                                                        • Heat sink effect
                                                          • Flowing blood in nearby vessels cools tissue, limiting heating of tumor tissue
                                                          • Presence of vessels or bronchi > 3 mm in diameter within ablation zone may be predictor of incomplete local treatment due to "heat sink" effect
                                                        • May require slow and lengthy treatment to effectively kill tumor
                                                    • MWA
                                                      • Physics
                                                        • Relies on dielectric heating
                                                          • Applied electromagnetic field causes water molecules in surrounding tissues to rotate at microwave's frequency
                                                          • Rapidly oscillating water molecules results in frictional heating, raising tissue temperature surrounding probe tip
                                                          • Higher water content = better heat absorption and conductivity = larger ablation zone
                                                        • As with RFA, goal of treatment is to sustain temperatures > 50 °C and ideally > 60 °C
                                                        • Advantages
                                                          • More rapid generation of high temperatures
                                                          • Not limited by increased impedance seen with tissue boiling/charring in RFA: This allows for much higher intratumoral temperatures, leading to larger ablation zones with relatively shorter treatment durations
                                                          • Less susceptible to heat sink
                                                          • Does not require grounding pads
                                                    • Cryoablation
                                                      • Physics
                                                        • Causes tumor necrosis through rapid cell freezing
                                                          • Multifaceted cellular death: Protein denaturation, cell membrane rupture, vessel thrombosis/ischemia
                                                        • Joules-Thomson effect
                                                          • Rapid expansion of argon gas at applicator tip leads to rapid drop in temperature (Joules-Thomson effect), cooling surrounding tissue: Temperatures can range from -80 to -150 °C
                                                          • To induce thaw cycle, compressed helium is circulated within applicator; expansion of helium at tip leads to rapid increase in temperature
                                                        • Process consists of alternating freezing and thawing cycles
                                                          • Triple cycle is typically used in lung (3-minute freeze, 3-minute passive thaw, 7-minute freeze, 3-minute passive thaw, 10-minute freeze followed by variable active/passive thaw to raise temp to 22 °C
                                                          • Nonlung ablation typically consists of 2 freeze cycles of variable length, depending on "ice ball" growth (10-minute freeze followed by 8-minute thaw cycle common)
                                                        • Multiple probes can be used to treat large tumors
                                                      • Advantages
                                                        • Decreased procedure associated pain
                                                        • Real-time visualization of treatment area
                                                          • "Ice ball" readily visible with CT/US/MR guidance
                                                        • Ablation zone can be modulated by probe placement and modulating freeze power and time of each probe to create shapes that ensure tumor and margin coverage
                                                        • Data suggests increased efficacy of cryoablation compared to RFA/MWA in treating renal tumors
                                                        • Prospective data suggests efficacy comparable to partial nephrectomy, which is standard of care
                                                      • Disadvantages
                                                        • Longer ablation time than thermal-based techniques
                                                        • More expensive, as multiple probes may be required
                                                        • System requires gas availability and storage

                                                  PREPROCEDURE

                                                  • Indications

                                                    • Contraindications

                                                      • Preprocedure Imaging

                                                        • Getting Started

                                                          PROCEDURE

                                                          • Patient Position/Location

                                                            • Alternative Procedures/Therapies

                                                              • Baseline Imaging and Planning

                                                                • Probe Insertion/Positioning

                                                                  • Ancillary Procedures

                                                                    • Intraprocedural Monitoring of Patient and Treatment

                                                                      • Completion Imaging and Recovery

                                                                        POST PROCEDURE

                                                                        • Follow-Up

                                                                          OUTCOMES

                                                                          • Complications

                                                                            • Expected Outcomes

                                                                              Selected References

                                                                              1. Genshaft SJ et al: Society of Interventional Radiology multidisciplinary position statement on percutaneous ablation of non-small cell lung cancer and metastatic disease to the lungs: endorsed by the Canadian Association for Interventional Radiology, the Cardiovascular and Interventional Radiological Society of Europe, and the Society of Interventional Oncology. J Vasc Interv Radiol. 32(8):1241.e1-12, 2021
                                                                              2. Genshaft SJ et al: Society of Interventional Radiology quality improvement standards on percutaneous ablation of non-small cell lung cancer and metastatic disease to the lungs. J Vasc Interv Radiol. 32(8):1242.e1-10, 2021
                                                                              3. Gunn AJ et al: Society of Interventional Radiology quality improvement standards on percutaneous ablation in renal cell carcinoma. J Vasc Interv Radiol. 31(2):195-201.e3, 2020
                                                                              4. Morris CS et al: Society of Interventional Radiology position statement on the role of percutaneous ablation in renal cell carcinoma: endorsed by the Canadian Association for Interventional Radiology and the Society of Interventional Oncology. J Vasc Interv Radiol. 31(2):189-94.e3, 2020
                                                                              5. Izzo F et al: Radiofrequency ablation and microwave ablation in liver tumors: an update. Oncologist. 24(10):e990-1005, 2019
                                                                              6. Tafti BA et al: Lung ablation: indications and techniques. Semin Intervent Radiol. 36(3):163-75, 2019
                                                                              7. Mouli SK et al: The role of percutaneous image-guided thermal ablation for the treatment of pulmonary malignancies. AJR Am J Roentgenol. 209(4):740-51, 2017
                                                                              8. Wallace AN et al: Percutaneous image-guided cryoablation of musculoskeletal metastases: pain palliation and local tumor control. J Vasc Interv Radiol. 27(12):1788-96, 2016
                                                                              9. Zhang F et al: Prognostic factors for long-term survival in patients with renal-cell carcinoma after radiofrequency ablation. J Endourol. 30(1):37-42, 2016
                                                                              10. Lee H et al: Hepatectomy vs radiofrequency ablation for colorectal liver metastasis: a propensity score analysis. World J Gastroenterol. 21(11):3300-7, 2015
                                                                              11. US Cancer Statistics Working Group. United States Cancer Statistics: 1999–2012 Incidence and Mortality Web-based Report. Atlanta: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention and National Cancer Institute. 2015. http://www.cdc.gov/uscs
                                                                              12. Ahmed M et al: Image-guided tumor ablation: standardization of terminology and reporting criteria--a 10-year update: supplement to the consensus document. J Vasc Interv Radiol. 25(11):1706-8, 2014
                                                                              13. Gunn AJ et al: Percutaneous ablation of the small renal mass-techniques and outcomes. Semin Intervent Radiol. 31(1):33-41, 2014
                                                                              14. Hiraki T et al: Radiofrequency ablation for early-stage nonsmall cell lung cancer. Biomed Res Int. 152087, 2014
                                                                              15. Kurup AN: Percutaneous ablation for small renal masses-complications. Semin Intervent Radiol. 31(1):42-9, 2014
                                                                              16. Ridge CA et al: Epidemiology and staging of renal cell carcinoma. Semin Intervent Radiol. 31(1):3-8, 2014
                                                                              17. Belfiore G et al: Patients' survival in lung malignancies treated by microwave ablation: our experience on 56 patients. Eur J Radiol. 82(1):177-81, 2013
                                                                              18. Cucchetti A et al: Systematic review of surgical resection vs radiofrequency ablation for hepatocellular carcinoma. World J Gastroenterol. 19(26):4106-18, 2013
                                                                              19. Howlader N et al: SEER cancer statistics review, 1975-2012. http://seer.cancer.gov/csr/1975_2012/
                                                                              20. Kashima M et al: Complications after 1000 lung radiofrequency ablation sessions in 420 patients: a single center's experiences. AJR Am J Roentgenol. 197(4):W576-80, 2011
                                                                              21. Vogl TJ et al: Microwave ablation therapy: clinical utility in treatment of pulmonary metastases. Radiology. 261(2):643-51, 2011
                                                                              22. Hong K et al: Radiofrequency ablation: mechanism of action and devices. J Vasc Interv Radiol. 21(8 Suppl):S179-86, 2010
                                                                              23. Brace CL: Radiofrequency and microwave ablation of the liver, lung, kidney, and bone: what are the differences? Curr Probl Diagn Radiol. 38(3):135-43, 2009
                                                                              24. Gervais DA et al: Society of Interventional Radiology position statement on percutaneous radiofrequency ablation for the treatment of liver tumors. J Vasc Interv Radiol. 20(7 Suppl):S342-7, 2009
                                                                              25. Lencioni R et al: Response to radiofrequency ablation of pulmonary tumours: a prospective, intention-to-treat, multicentre clinical trial (the RAPTURE study). Lancet Oncol. 9(7):621-8, 2008
                                                                              26. Hiraki T et al: Pneumothorax, pleural effusion, and chest tube placement after radiofrequency ablation of lung tumors: incidence and risk factors. Radiology. 241(1):275-83, 2006
                                                                              27. Goldberg SN et al: Image-guided tumor ablation: standardization of terminology and reporting criteria. Radiology. 235(3):728-39, 2005
                                                                              28. Solbiati L et al: Percutaneous radio-frequency ablation of hepatic metastases from colorectal cancer: long-term results in 117 patients. Radiology. 221(1):159-66, 2001