When that nagging pain in your knee won’t go away, your doctor may recommend an X-ray to find out what’s going on. But you may have concerns about radiation exposure. Should you take the test?

If you’re like most people, you’re reluctant to question your doctor’s advice. And you probably shouldn’t flat out refuse a recommended medical test. However, recently, the medical community has come under scrutiny about the over-prescription of diagnostic tests.

MRIs, X-rays and CT-scans are useful for diagnosing a variety of medical conditions, and in many circumstances they’re safe. However, while radiation exposure from a single X-ray is quite low, having too many over your lifetime can put you at risk for cancer. You may also develop cataracts or skin burns.

Also, a report in the New England Journal of Medicine indicated that radiation from current domestic CT-scan use — about 62 million per year — may cause 1 in 50 future cases of cancer.

Even radiation-free MRIs aren’t completely safe. For instance, when taken using a solution called gadolinium it can cause a serious condition called NSF/NFD, where the skin begins to harden. Sometimes, internal organs are also affected.

Proof of Unnecessary Testing?

Several studies show that in some cases these tests do little to improve patient diagnosis and care. At the Oregon Health and Science University in Portland, researchers looked at six studies of 1,800 people with lower back pain. Patients who received imaging tests fared no better than patients who received standard treatment but no imaging.

More evidence comes from Dr. Albert Martin of the Department of Medicine at the University of California, San Francisco, School of Medicine. In a report published in an issue of the Western Journal of Medicine he states that some screening tests have become routine practice although there isn’t enough evidence to show they affect the result of patient care.

Disturbing Reasons for Overuse of Tests

Several factors are at play here. First, many hospitals and doctors don’t want to face lawsuits if a test wasn’t ordered for an illness that wasn’t successfully treated. Also, many patients have a perception that the more expensive tests, CT-scans and MRIs, are better at diagnosing a problem.

Particularly troubling is that many hospitals encourage their doctors to order tests as a way to boost revenue. For instance, in 2008 the Medicare allowable reimbursement for knee MRIs was $457.33, compared to only $43.39 for a four-view arthritis series of knee X-rays.

A Better Way to Prescribe Diagnostic Tests?

According to Dr. Martin, better knowledge of test ordering principles and a few testing strategies could significantly reduce unnecessary testing and costs. This would also reduce the risks patients face.

Some testing strategies that could help include better tracking of patient imaging tests, dose reduction, improved communication between different health care providers, and better education of patients and physicians.

What You Can Do to Protect Yourself

  • Give your doctor a complete medical history Existing medical conditions can affect your tests, for instance if you have a pacemaker and you’re undergoing an MRI. Give your doctor all the necessary information.
  • Find out why you need the test Make sure your doctor explains what the test does and what information he hopes to get from it.
  • Is your doctor an expert in your condition One study suggested that doctors may over-prescribe MRIs thinking it saves time for the orthopaedic surgeon and patient. Get a second opinion.
  • Find out if there’s an alternative For instance, doctors might recommend ultrasounds for pregnant women and children to reduce their exposure to radiation from X-rays.
  • Keep track of your tests Reduce the amount of testing you undergo by letting your doctor know when your last imaging tests were taken.
  • Find out the risks Your doctor should inform you about the risks of the test and give you any literature available on it.
  • Prepare properly For instance, you cannot wear jewelry during an MRI test. Or, some X-rays require you to swallow a liquid such as iodine; if you have an allergy to it, let your doctor know.
  • Wear protection During an X-ray you should wear a lead shield or vest. Also, earplugs can block out the noise during an MRI.
  • Don’t insist on a test Ask your doctor to explain why you don’t need the test. Then find out how he plans to treat your condition, including when to schedule follow-up visits to monitor it.


Study References:

Journal: New England Journal of Medicine Volume 357:2277-2284 Number 22
Date of Study: November 2007
Study Name: Computed Tomography — An Increasing Source of Radiation Exposure
Website: http://content.nejm.org/cgi/content/full/357/22/2277
Author(s): David J. Brenner, Ph.D., D.Sc., and Eric J. Hall, D.Phil., D.Sc.

Journal: Western Journal of Medicine 1982 May; 136(5): 456–461.
Date of Study: May 1982
Study Name: Computed Tomography — An Increasing Source of Radiation Exposure
Website: http://www.pubmedcentral.nih.gov/pagerender.fcgi?artid=1273827&pageindex=2#page
Author(s): Albert R. Martin, MD.

Journal: The Lancet Volume 373, Issue 9662, Pages 463 - 472

Date of Study: February 2009
Study Name: Imaging strategies for low-back pain: systematic review and meta-analysis
Website: http://www.ohsu.edu/xd/about/news_events/news/choulowbackpainstudy.cfm and
Author(s): Roger Chou, M.D., Rongwei Fu PhD, John A Carrino, Richard A Deyo MD