This trial investigates operator radiation doses when performing standardized procedures using two different means of radiation protection, namely conventional lead shield and apron versus suspended protection system (Zero-Gravity, ZG). The performed procedure is standard endovascular aortic repair (EVAR). The hypothesis is that ZG offers superior protection for the operator.

Endovascular aneurysm repair (EVAR) is less invasive than open surgery, yet the procedure causes sustained radiation exposure to the operator and has a potential risk of radiation-induced skin damage and later malignancy. The deterministic (threshold limited) adverse effects of radiation have been known since the invention of the X-ray in 1895, but the stochastic (non-threshold limited) adverse effects are not so apparent and thus need constant refinement. Diligent usage of radiation protection and abidance to ALARA (As Low As Reasonably Achievable) principles minimizes cumulative radiation exposure.

The lens of the human eye is very sensitive to radiation and cataract formation has been reported among medical interventional practitioners. Previous research into differences between conventional protection (apron and shields) and suspended personal protection (Zero Gravity, ZG) claims superior protection, especially to the lens, while using a suspended personal protection system. Ancillary lead glasses may be needed to fully protect the eyes. In other studies randomization of methods was deemed irrelevant due to expected dramatic differences between conventional and suspended protection systems. In addition standardization of procedures was lacking, because of cohort matching difficulties. The methods of measuring scattered radiation varies among previous studies and we have found the evaluation methods flawed.

The aim of this research is to evaluate the total radiation exposure to the interventionalist and assistant during infrarenal abdominal aortic aneurysm stent-grafting, while using either conventional protection (lead apron and shield) or a suspended personal protection system (Zero-Gravity, ZG). The ZG system consists of a lead shield that is suspended from the ceiling or a separate hanger that permits freedom of motion of the operator, and with no weight supported by the operator.

The total radiation doses have seen considerate reduction already in Helsinki, Finland and lower doses may influence the efficacy of the ZG system. Improper usage of the ZG protection gear as a whole can lead to inefficient protection.

The operator's subjective ergonomic feel and experience will be evaluated with a postoperative questionnaire.

The patients will be randomized into two groups: one where the operator will be using conventional protection (shield and apron) and one where the operator will be using the ZG system. The data will be collected during a four month period, which includes approximately 50 standardized EVAR operations.

Dosimeters will be used to collect the data during the procedures and are placed in various anatomical regions (eye, chest, leg, stomach, control outside protection). The exposure dosage to the eye is measured with EYE-D (Eye lens TLD dosimeter) and other measurements are done using DIS-1 dosimeters. Other data collected includes total fluoroscopy duration, total dose area product (DAP), entrance skin air KERMA (ESAK), and body mass index.

The anonymity and rights of participants will be protected. The health of patients is of uttermost importance and there is no difference in care received.

The planning and design has started since May 2019. Data collection will commence after dosimeter testing in September 2019 and last until December 2019. After data analysis the results will be disseminated in Spring 2020. Literature review will take place parallel to the research.

Inclusion Criteria:

• all patients eligible for standard EVAR at Helsinki University Hospital

Exclusion Criteria:

• any additional interventions such as embolization, recanalization, screw fixation