Evaluation of radiation dose and risk to the patient from coronary angiography

Coronary angiography is a commonly performed diagnostic procedure with life saving benefits for the patient. However, because of its potential to deliver a high radiation dose, caution is warranted.

The purpose of this study was to determine the effective dose to an average patient from coronary angiography, to estimate the associated radiation risk in terms of fatal malignancy, and to examine ways effective dose may be reduced.

The dose-area product data from 210 examinations was used to determine the effective dose to the average patient by means of a commercially available software programme. Subsequently, the effective dose was used to estimate radiation risk based on the population averaged probability coefficients given in ICRP 60 and contrasted against age-related risk coefficients from the NRPB. The components of effective dose and radiation risk were examined to identify the organs most at risk.

The average effective dose was found to be 3.4 +/- 1.3 mSv. The risk of fatal malignancy was estimated as 170 per million cases, or around one in 6000. The average lung dose was 14.7 mSv, with the risk of fatal lung cancer estimated as 125 per million cases or one in 8000.

The average effective dose in this study was less than half that of most other studies. The lung was identified as the critical organ and the estimated risk of fatal cancer amounted to an increase of 0.017% above the normal incidence for the general population. The study affirmed that using a reduced cine frame rate, low dose pulsed fluoroscopy, added copper filtration and a conscious effort to reduce screening time can significantly reduce patient dose.