67th Annual Meeting Abstracts

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Radiation Dose in CT-Guided Cryoablation of Renal Masses
Amy S Burns, *Allen R Goode, *Matthew J Bassignani, Noah S Schenkman
University of Virginia, Charlottesville, VA

Introduction: The use of image-guided therapy is increasing while health risks from exposure to ionizing radiation are increasingly reported. Our goal was to calculate the effective radiation dose received during CT-guided cryoablation of renal tumors and to compute the learning curve for the procedure.
Materials & Methods: A retrospective chart review from January 2008 to February 2009 found 17 patients that underwent renal mass percutaneous cryoablation. Using radiation dose estimates based on a standard anthropomorphic phantom from each procedure, the average effective radiation dose was estimated.
Results: A total of 11 males and 6 females underwent cryoablation. There were 10 right- and 9 left-sided renal masses (one patient had ablation of three left tumors). Average mass size was 2.7 cm (range 0.9 cm-5.9 cm), average fluoroscopy time was 55.8 seconds (range 25.1-143.4 seconds), and average effective dose was 8.13 mSv for the fluoroscopy portion and 19.67 mSv for the total procedure. Average effective fluoroscopy dose and total dose for the first five cases were 12.56 mSv and 21.56 mSv, respectively. For the last five cases, average effective dose for the fluoroscopy portion and total procedure were 4.12 mSv and 15.78 mSv, respectively.
Conclusions: Average effective radiation dose for the entire procedure was 19.67 mSv. For comparison, the effective dose for three-phase renal CT is 23.7 mSv. Average effective radiation dose in the first five is higher compared to the last five cases. Patients should be informed of potential radiation risks when selecting this treatment modality.

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