Data Analysis on Patient Exposures in Cardiac Angiography

Abstract

In cardiac interventional radiology the fluoroscopy time and the film length are dominating factors for the resulting exposure of patients. From experiments in laboratory conditions and from measurements in actual practice and empirical formula has been derived to calculate the kerma-exposure product as a function of fluoroscopy time and film length. To simulate actual medical practice as closely as possible during the experiments, reference procedures were composed for fluoroscopy and cine-angiography. Over a period of two years, data on fluoroscopy time and cine film length were collected in the clinical practice of a large cardiology department in a major hospital in the Netherlands. The data reference to nearly 3000 cardiac intervention procedures, 50/50 divided between cardio-angiography and percutaneous transluminal coronary angiography. The mean value for the kerma-area product over all cardiac procedures is approx. 40 Gy cm2. The relative standard deviation is 60%. From the distribution measured, it follows that about 20% of all cardiac procedures account for approximately half the collective dose for patients. The empirically derived fit-function to calculate the kerma-area product provides a useful method to analyse patient exposures in interventional radiology as an aid in the context of quality assurance of medical practice and ALARA programmes in radiological protection.