Proposal for Reducing the Operator Radiation Exposure Dose during 3D DSA Imaging under Carotid Artery Occlusion Tests (Matas and Allcock Test).

Objective: 3D DSA performed under carotid artery occlusion tests (Matas and Allcock test) while the operator manually compresses the patient's carotid artery may be performed as a preoperative evaluation. However, few known studies have quantified the operator's radiation exposure dose during 3D DSA under carotid artery occlusion tests. In this study, we measured the changes in the operator's radiation exposure dose during such imaging under different protective measures and assessed alternative protective measures for hand exposure apart from protective gloves and the operator's head and neck orientation, proposing a new protection method. Methods: We measured changes in the operator's radiation exposure dose under different protective measures. Specifically, we measured changes in lens dose on the operator's head and neck orientation and the use of protective equipment. Furthermore, we evaluated alternative protective measures for hand exposure aside from protective gloves. Results: In all measurement points, the lower measured dose was recorded when protective measures were implemented. The measured doses to the left and right lenses varied depending on the usage of protective equipment and the orientation of the operator's head and neck. The lowest measured dose to both lenses was recorded when the protective equipment and ceiling-suspended shield were used, and the operator's head and neck were turned toward the subject. The hand dose was the lowest when protective gloves were used (316.9 μGy), representing a 72% reduction compared with unprotected conditions. When the neck guard or lead plate was inserted underneath the measurement points, the hand dose decreased by approximately 29% (884.3 μGy) and 43% (657.6 μGy), respectively, compared with unprotected conditions. Conclusion: Our findings confirmed that operator radiation exposure dose can be reduced through protective measures. The lens exposure dose was minimized when protective equipment and the ceiling-suspended shield were used, and the operator's head and neck were turned toward the subject. While the protective effect of the lead plates was lower than that of protective gloves-which can be challenging to use during manual compression-the method of inserting a lead plate beneath the patient table and bending it along the shoulder was identified as another useful alternative.