Roughly 25 patients a day are wheeled into Intermountain Medical Center's "cath lab" for CT scans to look for calcium buildup in their coronary arteries.
Coronary artery scans the newest addition to radiologists' growing arsenal of diagnostic tools can aid doctors in diagnosing heart problems early. But they expose patients to 50 to 150 times the radiation of a chest X-ray, raising their risk for developing cancer later in life.
"We want to make sure patients are getting tests only for the right reasons," said cardiologist Donald Lappé at a news conference Wednesday touting a 9-month-old initiative aimed at ensuring just that.
Since August 2012 Intermountain Heathcare's 168 clinics and 22 hospitals have been tracking patients' cumulative radiation exposure from high-dose tests: CT scans, nuclear medicine scans and interventional radiology exams. Later the hospital chain hopes to also track X-rays, mammograms and other screens.
Generally the cancer risk from a single test is low, but radiation exposure is of growing concern in medicine.
The U.S. population's exposure to ionizing radiation has nearly doubled during the past two decades, largely due to medical tests, according to the U.S. Food and Drug Administration, which requires all hospitals to disclose radiation doses to patients upon request.
Intermountain is the first health system in the country to proactively report cumulative exposure to patients in an online electronic health record, said Lappé, medical director of Intermountain's cardiovascular clinical program.
Simply by focusing on radiation, Intermountain's cath lab has reduced patient exposure 20 percent, said Lappé. Cardiologists have devised ways to use lower doses in certain heart procedures without sacrificing diagnostic capability, he said.
Armed with this information patients are better poised to decide whether to skip a test or consider one that doesn't use radiation, such as an MRI or ultrasound, he added.
Still, the amount of radiation that raises a person's cancer risk is in dispute. There's little consensus on how to measure exposure, and the data can be hard to decipher for patients.
"That's the downside," said 29-year-old Josh Page, of Clearfield, who was told he was exposed to 97.3 millisieverts, or mSv, of radiation last winter during multiple CT scans at an Intermountain hospital.
"You can get online and explore on your own what that number means. But you really have no clue. Is that an incredible amount of radiation? Is this going to kill me?"
But Page has no second thoughts about the CT scans, which he says were necessary to examine the growth of cysts associated with his pancreatitis and determine whether he needed surgery.
"Just having the knowledge is good," he said. "Having pancreatitis drastically increases your risk of getting pancreatic cancer, so now I know I need to be careful and get checked."
But some medical physicists fear out-of-context exposure information can frighten patients away from life-saving tests and treatments.
Federal data peg the risk of getting cancer in anyone's lifetime at 45 percent. Some experts say exposure to 100 mSv of radiation can increase that risk by about 1 percent. An average abdominal CT scan clocks in at 10 mSv.
But those numbers are based on population studies and don't take into account risk factors such as a patient's age, said Peter Jenkins, a medical physicist at University Hospital.
University Hospital reports cumulative exposures to patients who ask for it and tailors the information to a patient's age, gender, body size, the number of scans performed and which organs were exposed.
"Each cell type responds differently and handles injury from radiation differently, so each organ will have a different sensitivity to radiation," Jenkins said. Young children are also more susceptible, he said.
Intermountain's reports don't include these nuances.
Finding a meaningful but easy-to-understand way to convey risk is the challenge facing all radiologists, said Todd Russell, director of radiology at St. Mark's Hospital, which also monitors exposure.
Even a person's occupation can alter risk, he said, noting people receive more radiation during an airplane flight than on the ground. "So if I'm a flight attendant how much more at risk am I from getting 10 CT scans than someone who works in an office?"
Bottom line, said Intermountain radiologist Karen Conner, patients want information. "People are more aware of these risks and want to know how to manage these risks and discuss it with their doctors," she said.
Your radiation risks
Everyone is exposed to "background" radiation from cosmic rays, radon gas and other naturally occurring substances.
By the 1980s the modern use of radioactive minerals in medicine, power generation and warfare, coupled with radiation from television sets, computer monitors and airport security, added to individuals' radiation exposure.
Today radiation in medicine accounts for about 40 percent of the average individual's lifetime exposure.
Source: Food and Drug Administration, Harvard University Heart Letter, 2009