P589 Stable Trends in Radiation Exposure Amongst Patients with a New Diagnosis of Inflammatory Bowel Disease at an Irish Tertiary Referral Hospital

Abstract

Background The utilisation of diagnostic imaging has risen dramatically over time. IBD patients are particularly vulnerable to this inclination. We evaluated trends in the radiation doses to which our service exposed our new IBD referrals over time. Methods Searches of new referrals to our IBD clinic during two 24-month periods beginning 01/06/2005 (n=84) and 01/01/2013 (n=63) were conducted. The numbers of AXRs, CT APs, Barium Swallows, Meals, Follow-Throughs and Enemas, CT Colonographies and MRI SBs were collated for each patient for the five-year period subsequent to their first attendance. The dataset was irrevocably anonymised. Cumulative effective radiation doses were calculated using estimates provided in leading radiology journals. Linear regression using the ordinary least squares method examined the relationship between cumulative dose, period of diagnosis, age, gender and category of IBD. Results The mean cumulative effective radiation doses for the earlier and later periods were 4.7mSv (95% CI, 1.86 to 7.54) and 7.4mSv (95% CI, 3.60 to 11.26) respectively. No significant relationship was demonstrated between age (-0.03mSv, 95%CIs: -0.20, 0.12), male gender (0.69mSv, 95%CIs: -4.00, 5.39), or later referral period (3.06mSv, 95%CIs: -1.67, 7.78) and cumulative dose. A diagnosis of Crohn’s (as opposed to UC) had a strongly positive relationship with total radiation dose (5.89, 95%CI: 1.07, 10.70). 12 MRI small bowels were completed during period 2, none during period 1. Conclusion Our evaluation shows an upward trend, failing to meet statistical significance, in the radiation doses to which patients with new diagnoses of IBD were exposed to by our service.