Radiation doses and estimated risk from angiographic projections during coronary angiography performed using novel flat detector

Coronary angiography (CA) procedure uses various angiographic projections to elicit detailed information of the coronary arteries with some steep projections involving high radiation dose to patients. This study intends to evaluate radiation doses and estimated risk from angiographic projections during CA procedure performed using novel flat detector (FD) system with improved image processing and noise reduction techniques. Real-time monitoring of radiation doses using kerma-area product (KAP) meter was performed for 140 patients using Philips Clarity FD system. The CA procedure involved seven standard projections, of which five were extensively selected by interventionalists. Mean fluoroscopic time (FT), KAP, and reference air kerma (Ka,r) for CA procedure were 3.24 min (0.5-10.51), 13.99Gycm2 (4.02-37.6), and 231.43 mGy (73.8-622.15), respectively. Effective dose calculated using Monte Carlo-based PCXMC software was found to be 4.9mSv. Left anterior oblique (LAO) 45° projection contributed the highest radiation dose (28%) of the overall KAP. Radiation-induced risk was found to be higher in females compared to males with increased risk of lung cancer. An increase of 10%-15% in radiation dose was observed when one or more additional projections were adopted along with the seven standard projections. A 14% reduction of radiation dose was achieved from novel FD system when low-dose protocol during fluoroscopy and medium-dose protocol during cine acquisitions were adopted, compared to medium-dose protocol.