Despite universal consensus that computed tomography (CT) overwhelmingly benefits patients when used for appropriate indications, concerns have been raised regarding the potential risk of cancer induction from CT due to the exponentially increased use of CT in medicine. Keeping radiation dose as low as reasonably achievable, consistent with the diagnostic task, remains the most important strategy for decreasing this potential risk. This article summarizes the general technical strategies that are commonly used for radiation dose management in CT. Dose-management strategies for pediatric CT, cardiac CT, dual-energy CT, CT perfusion and interventional CT are specifically discussed, and future perspectives on CT dose reduction are presented.

Objective

For diagnosis, assessing disease activity, complications and extraintestinal manifestations, and monitoring response to therapy, patients with inflammatory bowel disease undergo many radiological studies employing ionizing radiation. However, the extent of radiation exposure in these patients is unknown.

Methods

A population-based inception cohort of 215 patients with inflammatory bowel disease from Olmsted County, Minnesota, diagnosed between 1990 and 2001, was identified. The total effective dose of diagnostic ionizing radiation was estimated for each patient. Linear regression was used to assess the median total effective dose since symptom onset.

Results

The number of patients with Crohn's disease and ulcerative colitis was 103 and 112, with a mean age at diagnosis of 38.6 and 39.4 yr, respectively. Mean follow-up was 8.9 yr for Crohn's disease and 9.0 yr for ulcerative colitis. Median total effective dose for Crohn's disease was 26.6 millisieverts (mSv) (range, 0–279) versus 10.5 mSv (range, 0–251) for ulcerative colitis (P < 0.001). Computed tomography accounted for 51% and 40% of total effective dose, respectively. Patients with Crohn's disease had 2.46 times higher total effective dose than ulcerative colitis patients (P = 0.001), adjusting for duration of disease.

Conclusions

Annualizing our data, the radiation exposure in the inflammatory bowel disease population was equivalent to the average annual background radiation dose from naturally occurring sources in the U.S. (3.0 mSv). However, a subset of patients had substantially higher doses. The development of imaging management guidelines to minimize radiation dose, dose-reduction techniques in computed tomography, and faster, more robust magnetic resonance techniques are warranted.