Diagnostic reference levels and median doses for common clinical indications of CT: findings from an international registry

D. Bos*, S.I. Yu, J. Luong, P.L. Chu, Y.F. Wang, A.J. Einstein, J. Starkey, B.N. Delman, P.A.T. Duong, M. Das, S. Schindera, A.R. Goode, F. MacLeod, A. Wetter, R. Neill, R.K. Lee, J. Roehm, J.A. Seibert, L.F. Cervantes, N. KasraieP. Pike, A. Pahwa, C.R.L.P.N. Jeukens, R. Smith-Bindman

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Ob jectives The European Society of Radiology identified 10 common indications for computed tomography (CT) as part of the European Study on Clinical Diagnostic Reference Levels (DRLs, EUCLID), to help standardize radiation doses. The objective of this study is to generate DRLs and median doses for these indications using data from the UCSF CT International Dose Registry. Methods Standardized data on 3.7 million CTs in adults were collected between 2016 and 2019 from 161 institutions across seven countries (United States of America (US), Switzerland, Netherlands, Germany, UK, Israel, Japan). DRLs (75th percentile) and median doses for volumetric CT-dose index (CTDIvol) and dose-length product (DLP) were assessed for each EUCLID category (chronic sinusitis, stroke, cervical spine trauma, coronary calcium scoring, lung cancer, pulmonary embolism, coronary CT angiography, hepatocellular carcinoma (HCC), colic/abdominal pain, appendicitis), and US radiation doses were compared with European. Results The number of CT scans within EUCLID categories ranged from 8,933 (HCC) to over 1.2 million (stroke). There was greater variation in dose between categories than within categories (p < .001), and doses were significantly different between categories within anatomic areas. DRLs and median doses were assessed for all categories. DRLs were higher in the US for 9 of the 10 indications (except chronic sinusitis) than in Europe but with a significantly higher sample size in the US. Conclusions DRLs for CTDIvol and DLP for EUCLID clinical indications from diverse organizations were established and can contribute to dose optimization. These values were usually significantly higher in the US than in Europe.
Original languageEnglish
Pages (from-to)1971-1982
Number of pages12
JournalEuropean Radiology
Issue number3
Early online date13 Oct 2021
Publication statusPublished - Mar 2022


  • Tomography
  • X-ray computed
  • Adult
  • Diagnostic reference levels
  • United States
  • Registries
  • RISK

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