A new study has identified large differences in radiation doses used for computed tomography (CT) scans. However, rather than the variation being mainly due to differences in the patients scanned or the machine used, the authors say these differences are mainly due to how the scanners are used by medical staff.
Researchers analysed data from over 2 million CT scans performed on 290 machines across 151 institutions in seven countries. They included scans of the abdomen, chest, combined chest and abdomen, and head collected between November 2015 and August 2017.
They found large variation in doses across countries. After adjustment for patient characteristics, there was a four-fold range in mean effective dose for abdominal scans and a 17-fold range in proportion of high dose scans (4-69%). Similar variation persisted for chest scans, and combined chest and abdomen scans. In multivariable analysis, the dose variation across countries was primarily attributable to institutional decisions regarding technical parameters.
The authors said the findings suggest that optimising doses to a consistent standard is possible, but say this would require more education and international collaboration to set benchmarks for optimum target doses.
The findings are published in the BMJ.