The American College of Radiology white paper on radiation dose in medicine:deep impact on the practice of cardiovascular imaging

Abstract

In April 2007, the American College of Radiology released the "White Paper on Radiation Dose in Medicine". The Blue Ribbon panel members included private practice and academic diagnostic radiologists, medical physicists, representatives of industry and regulatory groups, and a patient advocate. The panel concluded that the expanding use of imaging modalities using ionizing radiations such as CT and nuclear medicine may result in an increased incidence of radiation-related cancer in the exposed population in the not-too-distant future, and this problem can likely be minimized by preventing the inappropriate use of such imaging and by optimizing studies that are performed to obtain the best image quality with the lowest radiation dose. The White Paper set forth practical suggestions to minimize radiation risk, including education for all stakeholders in the principles of radiation safety and preferential use of alternative (non-ionizing) imaging techniques, such as MRI and ultrasound. These recommendations are especially relevant for cardiologists, who prescribe and/or practice medical imaging examinations accounting for at least 50% of the total effective dose by radiation medicine, which amounts to an equivalent of about 160 chest x-rays per head per year in US. Were they be enacted, these simple recommendations would determine a revolution in the contemporary way of teaching, learning and practising cardiology.

Figure 1

Medical and natural sources of radiation. Modified from ref 1, and updated with 2006 data from ref. 3. The effective dose of 1 mSv is equivalent to 50 chest x-rays. The per-head dose of ionizing radiation from clinical imaging exams in the United States increased almost 600 percent from 1980 to 2006.

Figure 2

Graphical presentation of cancer risk and radiation dose (in multiples of exposure from a conventional chest x-ray exam) for some common cardiovascular examinations. Modified from ref. 7, on the basis of novel estimates of BEIR VII (ref. 21).

Figure 3

Risk stratified according to age and gender. The risk is 37% higher in women than in men, and 4-fold higher in children <1 year than in adults. The risk is reduced by one-half in elderly (>80 years). Redrawn and modified from ref. 7, on the basis of novel estimates of BEIR VII (ref. 21).

Figure 4

The cumulative exposure of doses (y axis, left) and corresponding risk (y axis, right) with a standard, radiation-insensitive, diagnostic algorhythm for coronary artery disease. In the x-axis, we listed some common cardiologic examinations with the corresponding doses (1 mSv = 50 chest x-rays). The threshold of 50 mSv of epidemiological evidence is surpassed by a typical cardiologic patient with known or suspected coronary artery disease, in one single hospital admission.