Skyrocketing numbers of expensive medical imaging procedures - from CT scans to nuclear stress tests - are not just straining the nation's health care system, but are exposing patients to significant amounts of potentially cancer-causing radiation even though little research has been done into whether those tests actually make people healthier, a new study suggests.
The tests, say the study's authors, may be doing more harm than good.
"One reason why these tests are being used more is they're getting better and better and they're an extremely helpful part of diagnosis and treatment," said Dr. Reza Fazel, a cardiologist at Emory University School of Medicine in Atlanta and the lead author of a study in today's New England Journal of Medicine. "But just because we have them doesn't mean we should use them. ... There's a cost with these tests, and it's not just dollars but radiation risk."
No one disputes that advanced medical imaging has transformed medicine by enabling physicians to detect diseases and other medical problems at early stages - and even cure them. But with a rapid rise in expenditures on these tests, one of the fastest-growing costs in health care, there have been calls to rein in the use of unnecessary imaging. CT scans alone, which expose patients to moderate amounts of radiation for each test and are many times repeated, have quadrupled since 1992, according to a 2007 study.
Dr. Michael S. Lauer, director of the NIH's National Heart, Lung, and Blood Institute in Bethesda, said one of the biggest obstacles to restricting the number of radiologic tests is that not enough is known about whether most of them make patients feel better or live longer. X-rays for broken bones are obvious, but high-tech CT scans of the heart haven't been medically proved to improve health and they expose patients to much higher levels of radiation. "The problem that we have here is we don't know if there are too many [tests given], too few or just right," said Lauer, who was not part of the study.
He says only a few imaging tests - mammograms for discovering breast tumors, ultrasound of the abdomen for diagnosing aortic aneurysms - have been scientifically proved to save lives. Many have never been studied in large-scale clinical trials. In addition to leading to high doses of radiation, some tests can find cancers so small they might never have caused problems, leading to unnecessary surgeries and psychological distress.
