MedWire News: Some patients with inflammatory bowel disease are exposed to high amounts of radiation from diagnostic tests, which may increase their risk of other health problems, including cancer, US researchers have found.

"For diagnosis, assessing disease activity, complications and... monitoring response to therapy, patients with inflammatory bowel disease undergo many radiological studies employing ionizing radiation," explain Dr Darrell Pardi and colleagues from the Mayo Clinic in Rochester, Minnesota.

However, they add: "The extent of radiation exposure in these patients is unknown."

To investigate, the researchers studied data on 215 patients with inflammatory bowel disease from Olmsted County in Minnesota who were diagnosed with Crohn's disease or ulcerative colitis between 1990 and 2001.

The team analysed the patients medical records to calculate their exposure to radiation from diagnostic tests, such as conventional radiography, fluoroscopy and computed tomography.

Analysis revealed that, each year, patients with Crohn's disease were exposed to an average 3.1 mSv of radiation from diagnostic tests, while those with ulcerative colitis were exposed to an average 1.2 mSv of radiation.

These levels of radiation exposure are similar to those experienced by people in the general population, note the researchers.

But they also found that some patients with inflammatory bowel disease, such as those with a long duration of disease and severe symptoms, were exposed to significantly higher levels of radiation from diagnostic tests than other patients.

Writing in the American Journal of Gastroenterology, Dr Pardi and team summarise: "Overall, the annualised exposure to diagnostic ionizing radiation was equivalent to natural background radiation exposure. However, a subset of patients had substantially higher levels of exposure."

They conclude: "Clinicians caring for patients with inflammatory bowel disease need to consider the radiation exposure associated with radiologic studies, particularly repeated computed tomography scanning, and should only use these tests when the results will have an impact on the patient's management."