William R. Hendee

During the past few years, several articles have appeared in the scientific literature that predict thousands of cancers and cancer deaths per year in the U.S. population caused by medical imaging procedures that use ionizing radiation. These predictions are computed by multiplying small and highly speculative risk factors by large populations of patients to yield impressive numbers of "cancer victims." The risk factors are acquired from the Biological Effects of Ionizing Radiation (BEIR) VII report without attention to the caveats about their use presented in the BEIR VII report. The principal data source for the risk factors is the ongoing study of survivors of the Japanese atomic explosions, a population of individuals that is greatly different from patients undergoing imaging procedures. For the purpose of risk estimation, doses to patients are converted to effective doses, even though the International Commission on Radiological Protection warns against the use of effective dose for epidemiologic studies or for estimation of individual risks. To extrapolate cancer incidence to doses of a few millisieverts from data greater than 100 mSv, a linear no-threshold model is used, even though substantial radiobiological and human exposure data imply that it is not an appropriate model. The predictions of cancers and cancer deaths are sensationalized in electronic and print public media, resulting in anxiety and fear about medical imaging among patients and parents. Not infrequently, patients are anxious about a scheduled imaging procedure because of articles they have read in the public media. In some cases, medical imaging examinations may be delayed or deferred as a consequence, resulting in a much greater risk to patients than that associated with imaging examinations. © RSNA, 2012.

The growth in medical imaging over the past 2 decades has yielded unarguable benefits to patients in terms of longer lives of higher quality. This growth reflects new technologies and applications, including high-tech services such as multisection computed tomography (CT), magnetic resonance (MR) imaging, and positron emission tomography (PET). Some part of the growth, however, can be attributed to the overutilization of imaging services. This report examines the causes of the overutilization of imaging and identifies ways of addressing the causes so that overutilization can be reduced. In August 2009, the American Board of Radiology Foundation hosted a 2-day summit to discuss the causes and effects of the overutilization of imaging. More than 60 organizations were represented at the meeting, including health care accreditation and certification entities, foundations, government agencies, hospital and health systems, insurers, medical societies, health care quality consortia, and standards and regulatory agencies. Key forces influencing overutilization were identified. These include the payment mechanisms and financial incentives in the U.S. health care system; the practice behavior of referring physicians; self-referral, including referral for additional radiologic examinations; defensive medicine; missed educational opportunities when inappropriate procedures are requested; patient expectations; and duplicate imaging studies. Summit participants suggested several areas for improvement to reduce overutilization, including a national collaborative effort to develop evidence-based appropriateness criteria for imaging; greater use of practice guidelines in requesting and conducting imaging studies; decision support at point of care; education of referring physicians, patients, and the public; accreditation of imaging facilities; management of self-referral and defensive medicine; and payment reform.

OBJECTIVE. The complexity of diagnostic imaging has expanded dramatically over the past two decades. Over the same period, the time and effort devoted to teaching physics (the science and technology of the discipline) have diminished. This paradox compromises the ability of future radiologists to master imaging technologies so that they are used in an efficient, safe, and cost-effective manner. This article addresses these issues. CONCLUSION. Efforts involving many professional organizations are under way to resolve the paradox of the expanding complexity of medical imaging contrasted with the declining emphasis on physics in radiology residency programs. These efforts should help to reestablish physics education as a core value in radiology residency programs.