Staff radiation doses in interventional cardiology: correlation with patient exposure

Abstract

In pediatric interventional cardiology, cardiologists need to stay closer to the patient than during adult catheterization, and the use of biplane systems increases the scatter radiation. Occupational radiation risk is rather high, and estimation of lens doses becomes necessary. Deriving factors for assessing these doses from the patient doses displayed in catheterization laboratories can help in preserving staff radiation safety. A biplane X-ray system and polymethylmethacrylate plates of 4 to 20 cm to simulate pediatric patients have been used. Patient entrance dose rates, dose-area product, and doses to the eyes of the cardiologists for the typical operation modes have been measured. Correlations between patient and staff doses have been obtained. Scatter dose rates increase by a factor of 92 from low fluoroscopy to cine acquisition when phantom thickness increases from 4 to 20 cm. Scatter doses increase linearly with dose-area product for all the thicknesses. Administration of 1 Gy x cm(2) to the patient involves 7 microSv to the eyes of the cardiologist (without extra protection). In conclusion, the experimental correlation factors found between phantom and scatter doses allow a fairly good estimation of staff doses from the dosimetric patient data.