Factors affecting patient radiation exposure during routine coronary angiography in a tertiary referral centre.

Abstract

Cardiac catheterization is carried out by an increasing number of operators from district hospitals as well as tertiary referral centres. Procedures are not standardized and are at the discretion of individual operators. The purpose of this study was to describe the pattern of patient radiation dose and screening times associated with diagnostic cardiac catheterization, and explore determinants of radiation dose to patients and staff. Data were collected from 1337 diagnostic procedures carried out in two cardiac catheterization laboratories from January to June 1998. Screening time and radiation dose measured by dose-area product (DAP) meter were recorded. Status of the operator and type of investigation were determined. 22 operators had performed at least 15 left ventriculograms with coronary angiography (total 944 procedures). The average (+/- SD) was 40 (+/- 22) per operator. Screening times for individual operators varied from 2.0 (+/- 1.3) min to 5.0 (+/- 4.3) min with no relationship between time and number of cases. Consultants and visiting physicians had longer screening times and greater patient DAP readings. In comparison with 115 cases of coronary angiography alone, left ventriculography increased DAP reading from 14.24 (+/- 11.7) Gy cm2 to 20.26 (+/- 0.47) Gy cm2 (p < 0.0001). In 106 cases of coronary artery bypass graft angiography, an aortogram (n = 53) did not add significantly to radiation dose or screening time. A right heart catheter added approximately 5 min to screening time (9.13 (+/- 0.63) min with right heart (n = 83) vs 3.96 (+/- 0.12) min without right heart (n = 1234)), but did not affect radiation dose significantly. There is a wide range of screening times and radiation doses related to diagnostic cardiac catheterization. Visiting and consultant staff use greater radiation doses. Left ventriculography adds significantly to patients' radiation exposure. Aortography does not add significantly to radiation dose in cases of graft angiography.