CT scans have helped doctors find tumors, blood clots, broken bones and kidney stones, but there is increasing concern that they expose some patients to too much radiation.
The concern arose from the fact that doctors have ordered more and more CT scans, and numerous radiologists and medical organizations worried that patients would absorb harmful amounts of radiation over time.
The Joint Commission, which accredits health care organizations, issued an alert last August on the risks of diagnostic imaging.
Doctors and medical groups say CT scans have done considerably more good than harm. Nevertheless, they acknowledge that great care must be taken to make sure the dose of radiation is as low as possible while still providing the desired picture clarity.
In extreme instances, high doses of radiation can burn patients. The bigger concern, though, is that frequent CT scans over time may cause cancer.
"The risk is small, but I think it's there," said Thomas Lane, diagnostic radiation physicist at the Nebraska Medical Center.
Susan E. Bissell of Omaha has had many CT scans and isn't especially concerned about it. That's because she's been in a 13-year battle with cancer. Her breast cancer eventually moved to her brain, and CT scans have helped doctors know where the cancer is situated.
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Bissell, 50, credited those CT scans with enabling doctors to pinpoint and target her cancer.
"I would be dead right now without that CT scan," said Bissell, who had her latest CT scan last week. "It saves my life."
The number of CT scans done in the United States increased from about 3 million in 1980 to close to 80 million two years ago, said Dr. Allen Dvorak, associate medical director at UniNet Health Network, a combined enterprise of Alegent Health, Creighton University Medical Center, physicians and others.
There are several reasons for the increase. CT scans have improved, making them an increasingly powerful tool in diagnosing diseases. "The capabilities of CT are amazing," Dvorak said. "It is unbelievable, the quality."
CT scans have enabled physicians to diagnose diseases in many cases without doing exploratory surgeries.
The scanners now are available in small-town hospitals, and more patients demand that CT scans be used in their cases, said Dr. Thomas Dworak, interim chairman of the radiology department at Creighton University Medical Center. Physicians also use CT scans as defensive strategies to avoid potential malpractice lawsuits.
And some physicians own imaging equipment. The more scans done, the better financially for those physicians.
In the past few years, numerous organizations have weighed in on the need for meticulousness when ordering and using CT scans.
CT scans typically deliver the most radiation, but PET scans, X-rays, mammograms and some other forms of imaging also use ionizing radiation, which is the kind of radiation in question. MRIs and ultrasounds do not.
The American College of Radiology and other medical groups have conducted two national campaigns to encourage hospitals, clinics and doctors to order only necessary scans. Image Gently, begun in 2008, was directed toward CTs and other scans for children, and Image Wisely, begun in late 2010, involved adult patients.
CT scans that must be done frequently on young patients are of special concern. Among other reasons, children who receive numerous CT scans are at greater risk of cancer because radiation doses accumulate over a lifetime.
Further, the federal government this year has begun requiring freestanding imaging centers to gain accreditation from the American College of Radiology, Joint Commission or some other qualified group.
CT scans basically combine special X-ray technology with computerization to produce multiple pictures of the body's interior, according to the ACR. Scans of internal organs, bones, tissue and blood vessels provide greater clarity and better detail than X-rays, the ACR said.
While harm can occur from the cumulative effect of many CT scans, using insufficient radiation increases the possibility of inadequate images and misdiagnosis, and may lead to more scans, the Joint Commission said.
Radiation experts have an acronym for using just the right dose and no more: ALARA, which stands for "as low as reasonably achievable." In some cases, an MRI can be used instead of a CT scan.
"I think it is an ongoing concern," Richard Morin, chairman of the ACR safety committee, said of exposing patients to radiation. Morin has a doctorate in medical physics and is a medical physicist with the Mayo Clinic in Jacksonville, Fla.
The Nebraska Medical Center's Thomas Lane, who has a doctorate in radiation sciences, said horrible cases in which patients absorbed extremely high doses of radiation have received publicity over the past few years. A technologist in California activated CT scan equipment repeatedly, burning the side of a boy's face in 2009. In another California case that year, dozens of stroke victims received far too much radiation because a technologist had the machine on the wrong setting.
Morin said cases in which patients receive too much radiation from a CT scan generally are human error. Radiologists say it's not difficult for a skilled operator to set the machine so it emits the right amount of radiation.
Nevertheless, Morin and others said, one setting doesn't fit all. The dose hinges on the size of the patient and the organ or body part being scanned.
Susan Bissell said CT scans have played a big role in her ability to continue fighting cancer, and she intends to keep battling.
"I have a granddaughter I'd like to see finish high school," Bissell said. The granddaughter is 9 years old.
Contact the writer:
402-444-1123, rick.ruggles@owh.com
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