Intended for healthcare professionals


Unacceptable variation in radiation doses from CT scans

BMJ 2019; 364 doi: (Published 14 January 2019) Cite this as: BMJ 2019;364:l165

Linked research

International variation in radiation dose for computed tomography examinations

  1. Peter Vock, senior consultant1
  1. 1Department of Diagnostic, Therapeutic, and Paediatric Radiology, Bern University Hospital, CH-3010 Bern, Switzerland
  1. Correspondence to: P Vock peter.vock{at}

National standards would help protect patients from unnecessary risk

Substantial variations in radiation doses from diagnostic radiological examinations have often been observed.12 While differing patient populations and non-uniform methodologies have contributed to this variation, some patients have likely been exposed to higher radiation doses than required and, thus, exposed to the health risks of ionising radiation.

In a linked paper (doi:10.1136/bmj.k4718),3 Smith-Bindman and colleagues are to be commended for going beyond confirming dose variations for the most frequent computed tomography (CT) examinations, to more detailed quantification and analysis using a large database of more than two million examinations from 151 institutions in seven countries. Their study included CT imaging of the chest, abdomen, (separately or combined), and head of adult patients, and explored the contribution of patient, institutional, country, and protocol parameters in the observed variation.

Variations in radiation dose were modest when analysed by institution or machine characteristics, including patient volumes and …

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