Radiation Exposure Dose Reduction according to ECG Window Acquisition Range Setting in Coronary Artery CT Angiography

This study was to reduce the radiation exposure dose of recipients by setting the ECG window acquisition range appropriately during Coronary artery CT Angiography (CCTA) examination. Group 1 (control group) opened ECG window acquisition range to 65% to 75% using the relative delay scan (RDS), which is divided by percentage (%) based on the R-R peak interval of recipient's Average HR, and tested by setting pitch to auto. Group 2 fixed the pitch according to the recipient's HR under the same conditions as Group 1. Group 3 used absolute delay scan (ADS), which is divided by milliseconds (ms) based on the R-R peak interval of recipient's Average HR and fixed the ECG window acquisition range by 60 ms intervals. Group 4 narrowed the scan range from 68% to 73% under the same conditions as Group 1. The values of the mean, minimum, maximum, the volume CT dose index (CTDIvol), and dose length product (DLP) were compared. The exposure dose was reduced by more than 10% when acquired with ADS, not RDS mainly obtained from CCTA. Also, compared to the existing RDS, when the scan range was reduced by half, it was reduced by more than 20%. In conclusion, In CCTA testing, setting the ECG window acquisition range to 5% or 60 ms can reduce radiation exposure without compromising the best phase image acquisition and image quality.