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Abstract: SA-PO283

Variation in Radiation Dose of Computed Tomography Examinations Used for Renal Imaging

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical


  • Ganesan, Calyani, Stanford University, Palo Alto, California, United States
  • Chu, Philip W., UCSF, San Francisco, California, United States
  • Smith-Bindman, Rebecca, UCSF, San Francisco, California, United States

Computed tomography (CT) is the most commonly used imaging modality for the assessment of renal related problems (e.g. kidney stones or masses.) Patients may be exposed to higher than needed doses of ionizing radiation, a known carcinogen. The objective of this study is to examine current practice and quantify variation in radiation doses for urinary stone, renal mass, and urogram CT as a first step toward informing future quality-improvement efforts to reduce patient exposure to ionizing radiation.


We identified computed tomography examinations within the University of California San Francisco International Radiation Dose Registry which prospectively assembled CT examinations from 152 institutions in 6 countries between 2015 and 2018 for renal indications including kidney stones and renal masses. We examined variation in mean effective dose by facility and variation in the technical parameters used for these examinations.


We identified 90,459 urinary stone CT exams, 12,489 renal mass CT exams and 45,391 CT urograms. We found radiation dose varied with a threefold range in mean effective dose for urinary stone exams (4.9-13.6 mSv) and renal mass exams (12.7-41.2 mSv) and a sixfold range in mean effective dose for urograms (8.4-46.0 mSv). Adjusting for patient characteristics including size, and machine, make and model did not change these results and substantial variation in dose persisted.


Radiation dose varied substantially for urinary stone CT exams, renal mass CT exams and CT urograms, and these differences were not attenuated by adjusting for patient or machine factors. Doses could be substantially reduced if facilities adopted the protocols of the facilities where low dose protocols are used. This study highlights the need to adopt lower radiation dose protocols and standardize technical parameters to prevent patients from receiving unnecessarily high doses of ionizing radiation in the assessment of renal disease.


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