Estimation of equivalent organ and effective doses to patients undergoing coronary angiography and percutaneous coronary intervention procedures using Monte Carlo simulation

Abstract

The aim of the present study was to assess the patient-specific equivalent organ dose (HT) and effective dose (ED) delivered to individual patients from cardiovascular interventional radiology (CVIR) procedures and to compare these doses to those reported in the literature. The HT and EDs to 113 patients from two CVIR procedures: coronary angiography (CA) and percutaneous coronary interventions (PCI) were acquired from two major hospitals in Tanzania. The HT and EDs were estimated using the knowledge of the patient characteristics, patient related exposure parameters, geometry of examination, measurements of air kerma area product and Monte Carlo-based PCXMC software. The median HT in the present study for the lung, heart and oesophagus for the CA, were 47.1 mSv, 33.8 mSv, and 22.9 mSv, respectively, while for the PCI were 102.6 mSv, 77.5 mSv, and 51.9 mSv, respectively. The median values of ED as recommended by ICRP 103 for the CA and PCI procedures were 11.1 mSv and 24.7 mSv, respectively. The overall variations between individual EDs across the two hospitals differed by factors of up to 63.1 and 25.1, respectively for the CA and PCI procedures. The mean values of HT and EDs in the present study were, for the most part, higher than the reported values for India, Belgium and Italy, while comparable with those reported for Greece. The proposed diagnostic reference levels (DRLs) for the CA and PCI were for KAP 91.4 Gy cm2 and 129.4 Gy cm2, for fluoroscopy time 15.5 min and 28.4 min, for number of cine frames 791.5 and 1213.5, and ED 19.8 and 36.9 mSv, respectively. The observed wide range of exposure parameters and patient doses within and across the hospitals and the observed relatively high patient doses compared to those reported in the literature, call for the need to standardize examination protocols and optimise radiation dose to patients from CVIR procedures.