They reveal true images of the bones and soft tissues beneath our skin, without an incision. They can show lung tumors that are small enough to treat and blockages in blood vessels that can be removed before permanent damage is done.
Computerized tomography is among the 10 greatest medical advances of the last century, says David Feiglin MD. “It’s an amazing technology. Nobel Prizes were won because of it.”
But all this gee-whizzery comes with concern – that radiation exposure from repeated X-rays, CT scans and similar imaging techniques can, over time, cause cancer. The risks and concern are even greater for children, whose developing bodies are more susceptible to harm and who presumably will live many years during which cancer could develop.
“Most of the effects of radiation are felt decades down the line,” Dr. Marta Hernanz-Schulman told the HealthDay news service. She is the chair of the American College of Radiology Pediatric Imaging Commission, which urges the judicious use of imaging.
Feiglin says manufacturers of CT scanners have developed machines that use substantially less radiation. Some of the older machines in the Central New York community do not have this capability, but he says Upstate is using some of the newer CT imaging technology that has the capability of dramatically reducing patient radiation dosages. For example, a CT scan of the chest in the past that may have given the equivalent radiation of 50 chest x-rays now is more like the equivalent of five chest x-rays with the newer model machines.
In addition, Upstate University Hospital employs a pediatric radiologist, Gary Amundson MD and tailors CT scans to children, using the least amount of radiation possible. “You have to generate enough photons to get an image. You don’t want to have it so low that you have to have the scan redone,” he says.
Feiglin and Amundson predict that in the near future, cumulative records will be kept of an individual’s lifetime exposure to radiation through medical imaging – either by patients themselves or through a database that alerts physicians as they prepare to order scans for patients.
Of course medical imaging is not the only source of radiation exposure. Radiation is all around us, including in our bodies. Our smoke detectors, household appliances and the sun all are sources of radiation. Medical physicists call this “background radiation,” and a small amount is not considered dangerous.
Still, a group of nine medical specialty boards is calling for reductions in the use of medical imaging at a time when usage is up.
A study published in June in the Journal of the American Medical Association showed that among six large health care systems, the use of CT scans nearly tripled from 1996 to 2010. Researchers gave these reasons: physician and patient demand, improvement in the technologies that allow it to answer a broad range of questions, fear of medical malpractice lawsuits and uncertainty due to the lack of clinical guidelines on when to use imaging.
The medical boards – which represent cardiologists, allergists, radiologists, family medicine doctors and others – are calling the initiative Choosing Wisely and aiming it at physicians and patients.
At the same time, the Environmental Protection Agency advises that the use of X-rays and CT scans is a “gray area in which risk and benefit must be weighed by individuals and their doctors.” Ultrasound and magnetic resonance imaging do not rely on radiation to create their images, but those modalities aren’t always suitable for the type of images a physician needs.
“A lot of times, our job is to make sure the right scan is being done,” says Ken Galbraith Jr., an instructor in medical imaging sciences in Upstate’s College of Health Professions. “We spend a lot of time checking and double-checking.” That’s why patients who arrive for a scan often find themselves answering questions from the technicians about why they are there.
Medical physicist Kent Ogden says the number of CT scans performed at Upstate is on the decline because of a campaign to make sure any scan that is ordered has a purpose, that it is indicated for the patient. “If an exam is indicated,” he says, “then the benefits far outweigh the risks.
“The real risk from something like CT scans is actually pretty small, anyway,” Ogden says.
Time was, routine physical exams came with a chest X-ray. Not anymore. In general, physicians rely on medical imaging to assist with diagnoses. X-rays work well for bone fractures. MRIs and ultrasounds are better for injuries of the soft tissue. CT scans are used extensively in the treatment of traumatic injuries, and in oncology, and prior to surgery so that surgeons are not surprised by anything in the operating room.
Given the increased use of imaging, and the potential for overuse, medical experts suggest patients ask questions of their physicians before submitting to a scan. Ask how the scan will improve care. Ask if there are alternatives that don’t use radiation. Find out if the facility where the scan will be done is accredited by the American College of Radiology. And if the scan is for your child, ask if the radiation dose can be adjusted to child size.
Dave Clemente, Director of Medical Imaging Sciences at Upstate, says a fair question is: What do we hope to learn from this scan?
“I’m not challenging the doctor when I ask him or her. I’m just curious,” Clemente says. “Nowadays, doctors tend to respect that.”
Also keep in mind, if your doctor orders an additional scan, it does not necessarily mean he or she made a mistake. It may be that the image didn’t show what they were looking for, or that they are now looking for something else. If you are curious, ask.