This study sought to quantitatively evaluate the reduction of radiation dose in coronary angiography and angioplasty with the use of theDose Reduction Protocol (DRP) in routine clinical settings.

A Dose Reduction Protocol during coronary interventions was implemented at a tertiary care hospital in September 2018 which included lowering the Fluoroscopy frame rates from 15 fps to 8 fps, frequent use of ‘flurosave’, and decreasing the cine frame rate from 15fps to 10fps. Radiation exposure data for all coronary procedures done using DRP at a tertiary care hospital between October 2018 to November 2020 were collected. For comparison, radiation dose data from consecutive coronary procedures performed without DRP in the same center from April 2015 to September 2018 were evaluated. Data was segregated into diagnostic coronary angiography (CAG) and single-vessel Percutaneous Intervention (PCI). The parameters collected include fluoroscopy time, dose area product (PKA), skin surface entry dose(KAR), and fluoroscopy time (FT). Operators and operator practice did not change between the two evaluated periods. Patient characteristics were collected to evaluate the similarity of patient groups. Image quality was evaluated on a 5-grade scale in 30 patients of each group.

There were no significant differences between the 2 evaluated groups in gender, age, and weight. The median fluoroscopy time during coronary angiography was 2.4 min and 2.7 min in the two groups, and for single vessel angioplasty, it was 8.5 min and 9.3 min in both groups (not significant). The median dose area product was reduced from 2635.7 to 1296 mGym² (51%, p <0.001) in coronary angiograms and from 8822.1 to 2823 mGym² (68%, p <0.001) in single vessel coronary interventions using the DRP. The median skin surface entrance dose was reduced from 412 to 212 mGy (49%, p <0.001) in coronary angiograms and from 1649 to 478 mGy (71%, p <0.001) in single vessel coronary interventions using the Dose reducing Protocol. Image quality was graded as similar between the evaluated periods (4.0 vs 4.2, not significant).

By using a Dose Reducing Protocol, where the fluoroscopy frame rate is decreased to 8fps and the cine frame rate is decreased to 10fps, a substantial reduction in radiation exposure could be achieved without the need to prolong the procedure or fluoroscopy time. The image quality did not decrease significantly and clinically useful images were obtained using the dose-reducing protocol. In accordance with the ALARA principle of radiation exposure, a reduced frame rate, frequent use of the fluoro-save feature and reduced use of cine should be incorporated in all cath lab intervention procedures.