Fluoroscopic Organ and Tissue-Specific Radiation Exposure by Sex and Body Mass Index During Ureteroscopy

Introduction: Although radiation exposure from CT and plain film imaging has been characterized, the radiation received by patients during modern-era fluoroscopy has not been well described. The purposes of this study were to measure absolute organ and tissue-specific radiation doses during ureteroscopy and to determine the influence of body mass index (BMI) and sex on these doses. Materials and Methods: Eight cadavers underwent a simulated left ureteroscopy. Using a modern C-arm with automatic exposure control settings, thermoluminescent dosimeters were exposed for a fluoroscopy time of 145 seconds (mean time of clinical ureteroscopies from 2006 to 2008). Total tissue exposures were compared by BMI and between sexes using the Wilcoxon signed ranks test and the Mann-Whitney test with p < 0.05 considered significant. Results: Among all cadavers, radiation doses were significantly lower in all contralateral organs excluding the gonad (p < 0.012). Doses were similar bilaterally in the gonad in cadavers with BMI < 30, and in all organs in cadavers with BMI > 30 (p > 0.05). There were significantly higher mean bilateral gonadal doses in female cadavers (3.4 mGy left and 1.9 mGy right) compared with male cadavers (0.36 mGy left and 0.39 mGy right). The highest cancer risk increase was seen at the posterior skin equivalent to 104 additional cancers per 100,000 patients. Conclusion: Contralateral doses were lower for all organs except the gonad when the BMI was < 30. In contrast, when the BMI was > 30, there was no difference in radiation dose delivered to the ipsilateral and contralateral organs. Gonadal doses were significantly higher in female cadavers. Modern-era fluoroscopy remains a significant source of radiation exposure and steps should be taken to minimize exposure during ureteroscopy.