Cardiac imaging can deliver a significant dose of X-rays to a patient. According to a new survey, not enough is done to reduce exposure which may pose a health risk to the patient in the long term.

 Summary

Cardiac imaging is on the increase, to assess the extent of coronary artery disease. While the procedure gives valuable diagnostic information, it also subjects patients to x-rays. Researchers have surveyed the radiation dose to a group of patients and found wide variation. Also, strategies to reduce radiation exposure are not often used.

Introduction

Cardiac computed tomography angiography (CCTA) is a useful imaging technique for investigating patients who may have coronary heart disease. It is often used for a quick assessment of patients who present with chest pain in the emergency room. More CCTA scanners are becoming available around the world, so it is expected that more of these tests will be done. However, CCTA does expose a patient to radiation that could potentially be a health risk. There are ways of minimizing this dose. However, it has not been known, until now, how much exposure varies between clinics and also how often minimization strategies are actually used.

What was done

Researchers in Munich, Germany, investigated the dose of radiation received during CCTA for 1,965 patients in the Prospective Multicenter Study On Radiation Dose Estimates of Cardiac CT Angiography In Daily Practice (PROTECTION1). The patients were an international group, drawn from 21 university hospitals and 29 community hospitals. The exposure of radiation was calculated and independent predictors associated with radiation exposure analyzed.

What was found

The median exposure found in this study from CCTA was equivalent to 600 chest x-rays. And there was a big variation in exposure from clinic to clinic. Various technical factors were found to influence the radiation exposure as well as the weight and clinical status of the patient. Unfortunately, known strategies for reducing exposure to radiation from CCTA were not used all that often.

What this study means

Although CCTA is a valuable aid to the diagnosis of heart disease, it carries a small risk of cancer through radiation exposure. The risk-benefit ratio must therefore be considered carefully, particularly when repeat CCTAs are being carried out. And radiologists may need educating on the importance of carrying out the scan in such a way as to minimize the radiation exposure.

Source

Estimated radiation dose associated with cardiac CT angiography J. Hausleiter, T. Meyer,  et al, Journal of the American Medical Association, February 4, vol. 301, pp. 500--507