An audit of patient radiation doses during interventional cardiology procedures in Uttarakhand, India, and establishment of local diagnostic reference levels

The objective of this study was to investigate patient radiation doses by a dose audit of three common interventional cardiology (IC) procedures: coronary angiography (CA), percutaneous transluminal coronary angioplasty (PTCA) and CA–PTCA procedures performed in IC centres in the Uttarakhand state of India, for the establishment of local diagnostic reference levels (DRLs) and the estimation of average effective dose (E_av) for these procedures. For each procedure, the values of kerma-area product (P_KA), reference air kerma (K_a,r), fluoroscopy time (FT) and the number of cine images were recorded from 1233 CA, 458 PTCA and 736 CA–PTCA procedures performed over a 12-month period at 13 IC centres of the state. From the recorded dose data, 0.6%, 1.53% and 7.9% patients were identified to have exceeded the P_KA trigger level of 500 Gy cm² for possible skin injury for CA, PTCA and CA–PTCA procedures, respectively. The 3rd quartile of the distribution of the recorded P_KA values for each type of procedure was calculated to estimate local DRL values. The estimated values of DRLs and E_av were 37, 153 and 224 Gy cm², and 6.72, 23.97 and 34.79 mSv for CA, PTCA and CA–PTCA procedures, respectively. For about 77% of the surveyed centres, the recorded patient doses were in agreement with the international standards. The local DRLs proposed in this study may be used to achieve patient dose optimization during IC procedures and the obtained patient dose data may also be archived into national dose database for the establishment of national DRLs.