Underestimation of Occupational Radiation Exposure during Endovascular Abdominal Aortic Aneurysm Repair

During interventional procedures of endovascular abdominal aortic aneurysm repair (EVAR), the dosimeter was conventionally placed on chest facing toward the surgical table, instead of the main source of scatter radiation. Purpose of this study is to evaluate the underestimation of occupational radiation exposure. Phantom experiments were performed in a hybrid operating room equipped with an interventional angiography system. Electric personal dosimeters were placed at the level of eyes, chest, abdomen, and gonad of three positions, representing the principal operator (PO), assistant operator (AO), and sterile nurse (SN). Personal dose equivalent was measured with two different orientations of radiation detection, facing the table and facing the phantom, respectively. In addition to fluoroscopy, the dose produced by digital subtraction angiography was also measured to estimate the radiation exposure of routine EVAR. In this study, staff doses of 26 EVAR cases were also collected in our hospital to correlate the estimated dose. Our results show that the facing-phantom dose normalized by dose area product of patient is significantly higher than the facing-table dose when the latter is regularly seen in clinical practice. This underestimation could be even worse at a more distant position (e.g., AO and SN) as the incident angle of scatter radiation is larger. Besides, the estimated dose is highly correlated with the on-site measured dose (R2 ∼ 0.8) at chest and gonad of the PO.