The Effect of a Suspended Radiation Protection System on Occupational Radiation Doses During Infrarenal EVAR Procedures: A Randomised Controlled Study

Objective: To compare the protective effect of Zero Gravity (ZG) with conventional radiation protection during endovascular aneurysm repair (EVAR). Secondly, user experience was surveyed with a questionnaire on ergonomics. Methods: This was a single centre, prospective, randomised, two arm trial where 71 consecutive elective infrarenal EVAR procedures were randomised into two groups: (1) operator using ZG and assistant using conventional protection (n = 36), and (2) operator and assistant using conventional radiation protection (n = 35). A movable floor unit ZG system consists of a lead shield (1.0 mm Pb equivalent) for the front of the body and 0.5 mm Pb equivalent acrylic shielding for the head and neck. The ZG also includes arm flaps of 0.5 mm Pb equivalent covering the arm up to the elbow. Deep dose equivalent values, H_p(10) were measured with direct ion storage dosimeters (DIS) placed on various anatomical regions of the operator (axilla, chest, abdomen, and lower leg). Personal dose equivalent values, H_p(3) to eye lenses were measured in the operating and assisting surgeon using thermoluminescence dosimeters. The study was registered at the US National Institute of Health #NCT04078165. Results: Protection with the standard protection was superior in chest (0.0 vs. 0.1 μSv), abdomen (0.0 vs. 0.6 μSv), and lower leg (0.4 vs. 2.2 μSv) (p < .001). On the other hand, the ZG system yielded better shielding for the axilla (1.5 vs. 0.0 μSv) and eyes (6.3 vs. 1.1 μSv) of the operator. The use of ZG hampered the deployment of ancillary shields, which is particularly relevant for protection of the assisting surgeon. Users found ZG more cumbersome than conventional garments, it also impaired communication and reduced field of view. Conclusion: Both ZG and conventional radiation protection reduced radiation exposure. Conventional protection allows better manoeuvrability at the price of wider exposure of the upper arm and axilla. ZG indirectly impaired protection of the assistant.