Purpose: Cone beam CT (CBCT) is an important imaging technique. It is commonly used during prostate artery embolization (PAE) to identify the prostatic arterial anatomy and may help prevent non-target embolization. A critique of PAE is potential radiation exposure. The purpose of this study was to investigate the change of CBCT acquisition dose during PAE after optimization of technique.
Material and Methods: Routine PAE procedures performed by a single physician from June to December 2019 were retrospectively analyzed. All procedures were performed in a 40*40 cm flat panel detector angio-interventional suite (IGS740, GE Healthcare, Chicago, Illinois). The CBCT acquisition protocol was changed in October 2019 to obtain optimal image quality at the lowest dose. In addition to changing the acquisition parameters, the physician proceeded with appropriate collimation whenever the clinical context did not require a full field of view acquisition. Upon completion of the procedure, radiation exposure due to CBCT acquisition was assessed. The automated radiation report provided values for Dose Area Product (DAP) and Cumulative Air Kerma (CAK) attributed to CBCT acquisition and number of CBCTs performed.
Results: 28 bilateral consecutive PAE cases were included in the study, 14 cases before the protocol change and 14 cases after. The average number of CBCTs per cases was 4.4 before and 4.8 after. The average DAP attributed to CBCT acquisition was 44.6 Gy.cm2 after protocol change, versus 84.1 Gy.cm2 before (p-value <0.01). The average DAP per CBCT was reduced from 19 Gy.cm2 to 9.2 Gy.cm2 with the new protocol (p-value <0.01), as seen in Figure 1. Overall, DAP and CAK per case was 72 Gy.cm2 and 0.45 Gy with the new protocol versus 170 Gy.cm2 and 1.1 Gy previously.
Conclusions: Implementation of an optimized PAE CBCT acquisition protocol resulted in a dose per unit reduction by about half. The use of this protocol maintains a low radiation dose despite using a high number of CBCTs during PAE.