Biomedical Imaging Expert Answers Questions About New Study

Rebecca Smith-Bindman, MD, a professor of radiology and biomedical imaging at UCSF, answered these questions in light of a new study that shows that medical imaging is increasing even in health maintenance organization systems (HMOs), which don’t have a financial incentive to conduct them.

Q: What is the new study and what did it find?  

A: Our study just published in the medical journal JAMA (2012;307(22):2400-2409) highlights how frequently we use imaging and raises questions as to whether some of it can be reduced.

We looked at large numbers of patients enrolled within six integrated health care systems.  We studied 1 to 2 million patients each year, for 15 years. We found that:

• Imaging rates are high and have increased dramatically;
• There was tremendous variability across health plans in which tests were used;
• Doses that patients received from the exact same CT scans were highly variable across health plans;
• Many patients undergo relatively high doses because of repeat scanning; and
• A significant minority of patients is getting unacceptably high doses.

Q: What are the implications for patients?  

A: Patients need to be engaged in understanding the risks as well as the benefits of imaging, so that they can have more realistic expectations and make informed choices.

Most imaging is valuable, and necessary imaging has far more benefit than harm. However, there are definite harms from imaging, including high-dose radiation exposure as we highlighted in our study; false positive examinations that lead to further testing, diagnosis and treatment; and the over diagnosis of disease that leads to completely unnecessary treatment and labeling of patients with disease.

Patients should make more informed choices regarding when and how to image. That may lead them to request fewer tests, to defer some tests, and possibly to decide that they are willing to accept uncertainty and opt out of a particular test.

Q: Should patients opt out of medical imaging altogether?  

A: No. Patients should not be fearful of getting necessary testing, including CT, which can save lives. It is a remarkable technology that helps with many diagnoses, and when necessary can profoundly improve care. Rather, patients should discuss the tests with their doctors and should be vigilant in ensuring that their imaging is truly necessary.

The two ways to reduce your exposure to radiation from medical imaging are to eliminate unnecessary exams, and to receive more standardized and lower doses in necessary exams.

Q: How do I eliminate unnecessary medical imaging exams?

A: First, whenever an advanced imaging test is ordered for you or your loved one, you can and should ask if the test is really necessary, how will it help your care, and if you can wait and have it later. Some specific questions:

• Is this scan absolutely necessary?
• Will having the scan information change the management of my disease?
• Is it necessary to do it now?
• Can I wait until after seeing a specialist before getting the scan?
• Are there other, alternative tests?

Q: Other questions to ask?

A: If the test is a CT or a PET CT, ask about the dose and the steps taken to ensure that the dose is as low as possible and ask if there is another study that can be ordered that does not deliver radiation. And ask, how you can be sure the test will be done in the safest way possible.