Cumulative radiation dose and radiation risk from medical imaging in patients subjected to endovascular aortic aneurysm repair

This study was undertaken to quantify the cumulative effective dose (CED) of radiation and the dose to relevant organs in endovascular aortic repair (EVAR) patients, to assess radiation risks and to evaluate the clinical usefulness of multi-detector computed tomography (MDCT) follow-up. The radiation exposures were obtained from 71 consecutive EVAR patients with a follow-up duration a parts per thousand yen1 year. Dose calculations were performed on an individual basis and expressed as effective doses and organ doses. Radiation risk was expressed as risk of exposure-induced death (%), using the biological effects of ionising radiation model. Two radiologists independently assessed the images for abdominal aortic aneurysm expansion without endoleaks, thrombotic occlusion, endoleaks and device migration. They first reviewed arterial imaging alone and subsequently added non-contrast and delayed phases to determine the overall performance. The median total CED and annual CED were 224 and 104 mSv per patient-year. The median cumulative organ doses were 191, 205, 230, 269 and 271 mSv for lung, bone marrow, liver, colon and stomach, respectively. The average risk of exposure-induced death was 0.8 % (i.e., odds 1 in 130). All the findings related to EVAR outcome and leading to a change in patient management were visible during the arterial phase of the MDCT angiography. Omission of the unenhanced scan and the venous phase of the MDCT angiography would have led to a significant reduction of about 60 % of the associated MDCT radiation exposure in a single patient. EVAR patients received high radiation doses and the excess cancer risk attributable to radiation exposure is not negligible. The unenhanced scan and the venous phase of the MDCT angiography could have been omitted without compromising the utility of the examination and with a significant reduction of doses and associated risks.