Radiation Dose Index of Renal Colic Protocol CT Studies in the United States: A Report from the American College of Radiology National Radiology Data Registry

Abstract

Purpose-To determine radiation dose indexes for computed tomography (CT) performed with renal colic protocols in the United States, including frequency of reduced-dose technique usage and any institutional-level factors associated with high or low dose indexes.Materials and Methods-The Dose Imaging Registry (DIR) collects deidentified CT data, including examination type and dose indexes, for CT performed at participating institutions; thus, the DIR portion of the study was exempt from institutional review board approval and was HIPAA compliant. CT dose indexes were examined at the institutional level for CT performed with a renal colic protocol at institutions that contributed at least 10 studies to the registry as of January 2013. Additionally, patients undergoing CT for renal colic at a single institution (with institutional review board approval and informed consent from prospective subjects and waiver of consent from retrospective subjects) were studied to examine individual renal colic CT dose index patterns and explore relationships between patient habitus, demographics, and dose indexes. Descriptive statistics were used to analyze dose indexes, and linear regression and Spearman correlations were used to examine relationships between dose indexes and institutional factors.Results-There were 49 903 renal colic protocol CT examinations conducted at 93 institutions between May 2011 and January 2013. Mean age ± standard deviation was 49 years ± 18, and Address correspondence to C.L.M. (chris.moore@yale.edu). Online supplemental material is available for this article. Author contributions:Guarantor of integrity of entire study, C.L.M.; study concepts/study design or data acquisition or data analysis/interpretation, all authors; manuscript drafting or manuscript revision for important intellectual content, all authors; approval of final version of submitted manuscript, all authors; literature research, A.L., J.W., G.G., C.L.M.; clinical studies, M.G., J.W.; experimental studies, J.W.; statistical analysis, A.L., M.B., L.C., C.L.M.; and manuscript editing, A.L., M.B., L.C., J.W., G.G., C.L.M. The purpose of this study was to determine the radiation dose indexes for CT examinations performed with renal colic protocols in the United States, including how frequently reduceddose techniques are used and any institutional-level factors that are associated with high or low dose indexes. Disclosures of Conflicts of Materials and Methods Study SampleThe Dose Index Registry (DIR), part of the American College of Radiology-sponsored National Radiology Data Registry (www.nrdr.acr.org), receives deidentified data from individual CT examinations performed at participating institutions (21). Participating institutions send anonymized data to the DIR for all CT studies of all types that are performed, barring technical issues or scanner incompatibility. For each submitted study, the DIR includes the type of CT study, the technique factors for each acquisition, estimated CT dose index, and total dose-length product (DLP,...

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