Measurement and optimization of patient radiation doses in endovascular aneurysm repair

The study assessed radiation exposure during EVAR. Two types of patient dose were estimated: effective dose (ED), which allows estimation of radiation risk to the EVAR patient population; and Peak Skin Dose (PSD), which allows us assess the potential for an individual patient to receive a radiation skin injury. An ancillary aim was to examine dose optimization in EVAR procedures. Based on 111 EVAR cases we estimated average ED as 12.4 mSv. Cumulative patient dose in our centre was lower than other studies because the follow up of EVAR patients is based on ultrasound rather than CT. PSD calculated using a published conversion formula closely matched measurements with calibrated gafchromic film. 99% of patients had an estimated PSD of < 2Gy. Results indicate that skin injuries are possible, but very unlikely in EVAR procedures at our centre. EVAR is a high dose procedure and emphasis on dose optimisation is important. We broke the EVAR procedure into 15 steps and, in a phantom study, showed how skin dose changes as procedure steps are varied. The resulting dose matrix has the potential to be used as an educational tool to promote dose optimization.