Computed tomography (CT) and, more recently, CT enterography are excellent non-invasive tools for diagnosing Crohn’s disease, and for subsequent assessment of the disease, before and after therapy.1 In this light, and given the general availability and ease of use of CT machines, it is not surprising that CT is steadily replacing barium small-bowel follow-through as the radiological modality of choice for imaging Crohn’s disease.

There is, however, a potential downside, which is the radiation exposure produced by the CT scan. By their nature, CT scans result in radiation doses which are very much at the high end of those produced in diagnostic radiology, simply because a CT scan is effectively a large number of individual images that are electronically combined to produce a three-dimensional image. The effective dose involved in a CT scan is not large, but it is typically two to six times larger than that from barium small-bowel follow-through. Because of the typical long-term remission/relapse pattern of Crohn’s disease, together with the fact that is predominantly a disease of young people, Crohn’s disease patients are often imaged multiple times which, of course, correspondingly multiplies the radiation dose.

In this light, the report by Desmond et al2 in this issue of the journal (see page 1524) surveying trends in radiation exposure as a result of imaging Crohn’s …