What to know before giving, getting a CT scan

The use of CT scans has grown tremendously in the past three decades. The imaging tests, first widely used in the mid-1970s, have become a valuable tool for pinpointing tumors and blood clots, monitoring heart disease, and reducing the need for exploratory surgery. But there is evidence that their use has outpaced need.

The American Medical Association is taking public comment through the end of this week on a proposal to control use of the tests. There are a couple of good reasons for doing that.

For one, it could save money. For an abdominal CT scan, without use of a dye, performed in Boston-area doctor's office, Medicare will pay almost $300. Private insurers typically would pay more. That may not seem like much. But consider the total costs. In 2001, Medicare was billed for $1.2 billion in CT scans. In 2009, that figure was $2.3 billion.

Another goal: curbing patient exposure to the test's ionizing radiation. While there is no real consensus on how much radiation is too much, there is a general agreement that it is best avoided.

I talked with two specialists about what patients should know. But first, a few startling statistics:

  • Between 1980 and 2006, the number of CT scans performed each year in the United States jumped from 3 million to 62 million.
  • One-third of CT tests are not justified by medical need, according to the draft proposal.
  • At least 1 million children are exposed unnecessarily each year to radiation from CT scans.

The American College of Radiology and other specialists groups have been focused on this issue for years. Dr. James Thrall, that group's president and radiologist-in-chief at Massachusetts General Hospital, and Dr. David Seidenwurm, a radiologist in Sacramento, Calif., who served as an ACR representative to the consortium that drafted the proposal, said patients should ask some key questions before a scan:

Why this test? What is the doctor looking for exactly? How will the results of a CT scan be used to determine the course of care?

Is there an alternative? Could an ultrasound, an MRI, or a colonoscopy – none of which involves ionizing radiation – do the job instead? Of course some alternatives may have their own side effects, Seidenwurm said.

Who wins? Does the doctor have an ownership interest in the machine that will be used? Will they be paid for its use?

The last one is a biggie. Laws aimed at reducing such conflicts have loopholes. Studies show that doctors are more likely to recommend CT scans more often if they will get paid for it. According to one such study from 2007 led by Mass. General researcher Scott Gazelle, physicians who refer patients to get a scan within their own practice or even by members of their own specialty, rather than to radiologists, are twice as likely to recommend use of diagnostic imaging. The authors suggest that a financial benefit may be the motivator.

“It hurts me to have to say this about my own profession, but there are so many greedy people who are just taking money out of the system for no benefit to patients," Thrall said.

What do you think? Have you been referred for one too many CT scans? Or does the peace of mind that you experience in getting a clean test outweigh the risk of radiation? Doctors, what guidelines do you follow?

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Posted by Chelsea Conaboy, Globe Staff, April 26, 2011 10:00 AM