Chad Robert Tracy1, Paul Kogan1, Amit Gupta1, Jeffrey C Gahan2, Nithin P J Theckumparampil3, Sammy E Elsamra3, Zhamshid Okunov4, Shiliang Sun5, Chandana Lall6, Igor Lobko7, Jaime Landman4, Jeffrey A Cadeddu2, Louis R Kavoussi6. 1. 1 Department of Urology, University of Iowa , Iowa City, Iowa. 2. 2 Department of Urology, University Texas Southwestern Medical Center , Dallas, Texas. 3. 3 Rutgers Cancer Institute , New Brunswick, New Jersey. 4. 4 Department of Urology, University of California-Irvine , Orange, California. 5. 5 Department of Radiology University of Iowa , Iowa City, Iowa. 6. 6 Department of Radiology, University of California-Irvine , Orange, California. 7. 7 Department of Interventional Radiology, Hofstra North Shore-Long Island Jewish School of Medicine , Hempstead, New York.
Abstract
OBJECTIVE: To understand the effective radiation dose during percutaneous cryoablation (CA) and radiofrequency ablation (RFA) and characterize variables that may affect the individual dose. MATERIALS AND METHODS: The effective radiation dose was determined by conversion of the dose-length product from CT scans performed during percutaneous CA or RFA for patients with solitary renal masses (<4 cm) at four academic centers. Radiation dose per case was compared between patients and institutions using multivariate and univariate analysis. Lifetime attributable risk of cancer was calculated for each institution and utilized to determine the number needed to harm for a range of ages at the time of exposure. RESULTS: One hundred twenty-three patients met the inclusion criteria with a mean age of 71 years. Sixty-nine percent of patients were male, mean body-mass index (BMI) was 29.4, and mean tumor size was 2.2 cm. The mean effective radiation dose per ablation was 40 mSv (range 3.7-147). On multivariate analysis, only BMI and institution were associated with the radiation dose. No significant difference in radiation exposure was seen for RFA or CA procedures. CONCLUSIONS: Radiation exposure during percutaneous ablation is similar to a multiphase CT scan. However, there is wide variability in individual treatment exposure, varying from 3.7 to 147 mSv, depending primarily on institution and BMI. Standardization of protocols is required to achieve as low as reasonably achievable levels of radiation.
OBJECTIVE: To understand the effective radiation dose during percutaneous cryoablation (CA) and radiofrequency ablation (RFA) and characterize variables that may affect the individual dose. MATERIALS AND METHODS: The effective radiation dose was determined by conversion of the dose-length product from CT scans performed during percutaneous CA or RFA for patients with solitary renal masses (<4 cm) at four academic centers. Radiation dose per case was compared between patients and institutions using multivariate and univariate analysis. Lifetime attributable risk of cancer was calculated for each institution and utilized to determine the number needed to harm for a range of ages at the time of exposure. RESULTS: One hundred twenty-three patients met the inclusion criteria with a mean age of 71 years. Sixty-nine percent of patients were male, mean body-mass index (BMI) was 29.4, and mean tumor size was 2.2 cm. The mean effective radiation dose per ablation was 40 mSv (range 3.7-147). On multivariate analysis, only BMI and institution were associated with the radiation dose. No significant difference in radiation exposure was seen for RFA or CA procedures. CONCLUSIONS: Radiation exposure during percutaneous ablation is similar to a multiphase CT scan. However, there is wide variability in individual treatment exposure, varying from 3.7 to 147 mSv, depending primarily on institution and BMI. Standardization of protocols is required to achieve as low as reasonably achievable levels of radiation.