Probability of receiving a high cumulative radiation dose and primary clinical indication of CT examinations: a 5-year observational cohort study

C.R.L.P.N. Jeukens*, H. Boere, B.A.J.M. Wagemans, P.J. Nelemans, E.C. Nijssen, R. Smith-Bindman, J.E. Wildberger, A.M. Sailer

*Corresponding author for this work

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Objective High radiation exposure is a concern because of the association with cancer. The objective was to determine the probability of receiving a high radiation dose from CT (from one or more examinations within a 5-year period) and to assess the clinical context by evaluating clinical indications in the high-dose patient group. Design Observational cohort study. Effective radiation dose received from one or more CT examinations within a predefined 5-year calendar period was assessed for each patient. Setting Hospital setting. Participants All patients undergoing a diagnostic CT examination between July 2013 and July 2018 at the Maastricht University Medical Center. Primary and secondary outcome measures The primary outcome was the probability of receiving a high effective dose, defined as >= 100 mSv, from one or more CT examinations within 5 years as derived from a time-to-event analysis. Secondary outcomes were the clinical indication for the initial scan of patients receiving a high effective dose. Results 100 672 CT examinations were performed among 49 978 patients including 482 (1%) who received a high radiation dose. The estimated probability of a high effective dose from a single examination is low (0.002% (95% CI 0.00% to 0.01%)). The 4.5-year probability of receiving a high cumulative effective dose was 1.9% (95% CI 1.6% to 2.2%) for women and 1.5% (95% CI 1.3% to 1.7%) for men. The probability was highest in age categories between 51 and 74 years. A total of 2711 (5.5%) of patients underwent more than six CT examinations, and the probability of receiving a high effective dose was 16%. Among patients who received a high effective dose, most indications (80%) were oncology related. Conclusions The probability of receiving a high radiation dose from CT examinations is small but not negligible. In the majority (80%) of high effective dose receiving patients, the indication for the initial CT scan was oncology related.
Original languageEnglish
Article number041883
Number of pages9
JournalBMJ Open
Issue number1
Publication statusPublished - 1 Jan 2021


  • computed tomography
  • computed-tomography
  • exposure
  • health policy
  • radiation oncology
  • recurrent ct

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