Financial incentives also fuel the casual use of scans. “Radiology has become an enormous profit” center for hospitals, Smith-Bindman said. “The amount we get paid is very high” under fee-for-service systems.
Patient demand is a key factor. Many people, unaware of the radiation risk, push for tests in the erroneous belief that they signify cutting-edge care. “If a patient requests [a CT scan] and a doctor says no, it could be a good starting point for a conversation,” said Orly Avitzur, medical director for Consumer Reports. But too often, doctors feel pressed for time so they just order the test. “As a practicing neurologist, I can tell you it is a very tough thing to say, ‘No, this is not needed at this time.’ “
To determine whether a CT is necessary, Avitzur said, patients should ask why the scan is being done, how the results might affect treatment and whether an alternative such as ultrasound or an MRI could be used instead.
How Much Is Too Much?
Among radiologists, the debate about the risk of cancer from diagnostic CTs rages.
“Everything we do in medicine involves trade-offs,” said Smith-Bindman, who directs UCSF’s Radiology Outcomes Research Lab. “The risks of radiation are real, and radiation leads to cancer. I think the data are quite compelling and not that hard to understand.”
But others disagree. “I don’t think the risks are as clear-cut” as Smith-Bindman contends, said Mass General’s Brink, vice chairman of the board of the American College of Radiology. In a recent article he co-authored, Brink characterized the risk of cancer from diagnostic scans as “unproved” and “overemphasized,” based in part on uncertainty about the effect of radiation.
Scott Berger, director of neuroradiology at the Mount Kisco Medical Group in New York, agrees. “The risk of dying from a cancer that is not detected is thousands of times greater than” from radiation, he said. “These tests are lifesaving, they are great for patients.”
But Marta Hernanz-Schulman, medical director of radiology at the Monroe Carell Jr. Children’s Hospital at Vanderbilt in Nashville, is less gung-ho.
“Is radiation a real problem?” she asked. “We don’t know, but we need to act as if it were.” Studies performed in the United Kingdom in 2012 and Australia in 2013 found an increase in cases of leukemia and malignant brain tumors among children and young adults who had undergone CT scans. One concern, said Hernanz-Schulman, a past president of the Society for Pediatric Radiology, is that many children undergo CT scans in adult facilities and may receive excessive doses because scanners are not adjusted between patients.