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  5. Appropriate Use
  1. Initiative to Reduce Unnecessary Radiation Exposure from Medical Imaging

Appropriate Use

Several publications from the 2000s suggested that as many as 20%–50% of high-tech imaging procedures, such as CT scans, fail to provide information that improve patient welfare and therefore may represent, at least in part, unnecessary imaging services. An informal estimate, made at a 2001 conference, was that perhaps 10 – 30% of pediatric CT examinations were not necessary.

As a result, attention has turned to appropriate use of diagnostic imaging studies. A diagnostic imaging study can be considered appropriate when the expected health benefit (i.e., increased life expectancy, pain relief, reduction in anxiety, improved functional capacity) exceeds the expected negative consequences (i.e., mortality, morbidity, anxiety of anticipating the procedure, pain produced by the procedure, time lost from work) by a sufficiently wide margin that the procedure is worth doing.

Evaluation of appropriateness can be difficult, because in many cases, published appropriateness criteria are not applicable to all types of patients seen in routine practice. In many cases insufficient evidence exists for experts to achieve consensus on the appropriateness of a particular indication. (1) The 2014 RAND Corporation report on the Medicare Imaging Demonstration (MID) project suggested that between 4% and 26% of imaging studies that could be evaluated were inappropriate, depending on the specific imaging study and the institution at which appropriateness was evaluated.(1) The Rand report also reviewed a number of published reports of decision support system (DSS) use. A DSS synthesizes existing evidence on the effectiveness of each procedure, including appropriateness criteria developed by physician specialty societies. Physicians use DSS to help base decisions on the current evidence at the point of care. A DSS provides immediate feedback to the physician on the appropriateness of a test or treatment ordered for a patient. After the introduction of a DSS to aid physicians in selecting an appropriate examination, the rate of inappropriate examinations decreased in most published reports. DSS can improve the likelihood of appropriateness even when the vast majority of studies are already appropriate. For example, at Massachusetts General Hospital, the percentage of “low utility” studies decreased from 6% to 2% after the introduction of a DSS.

The FDA strongly promotes the efforts of other organizations in the area of appropriate justification of imaging exams through the development and adoption of appropriate-use criteria. An important aspect of reducing unnecessary exams is access to a patient's imaging history (see Education and Communication section). In addition, development and implementation of evidence-based appropriate use guidelines is crucial. Examples of efforts to promote appropriate use of imaging include:


1. Timbie JW, Hussey PS, Burgette L, et al. Medicare Imaging Demonstration Evaluation Report for the Report to Congress. Final Research report. Report RR-706-CMMS. The Rand Corporation, Santa Monica, CA; 2014.

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