Computed tomography (CT) is a scan of internal organs that creates cross-section images using X-rays. It’s a very popular kid on the medical technology block:
- Between 1980 and 2007, the number of CT scans performed in the U.S. increased from 3 million to 70 million.
- An estimated 29,000 future cancers, according to a National Cancer Institute study, will be related to scans done in 2007 alone.
- An estimated 1 in 3 imaging exams do not help the patient nor contribute to better outcomes.
This last, cold reality was delivered recently on KevinMD.com by Dr. Toni Brayer, an internal medicine practitioner. We have raised the flag of CT risks many times, and an increasingly larger segment of the medical community is concerned about the radiation this technology relies on.
We’ve also discussed the fact that a lot of patients are unaware that a CT scan involves radiation, or that radiation can be harmful. Brayer notes that a new study from the University of Washington shows that 1 in 3 people did not know that a CT scan exposed them to radiation, and those who did underestimated the amount of radiation it delivered.
“A CT scan,” Brayer writes, “delivers a mega-dose of radiation, as much as 500 times that of a conventional X-ray.”
The more scans you have, the higher your risk. Radiation risk is cumulative.
Brayer explains a medical situation called “incidentalomas”; that’s when you get, say, an X-ray for a suspected case of pneumonia that also shows something that can’t be explained. So the radiologist might recommend a follow-up CT scan to diagnose that, and you’re on your way to possibly unnecessary-and dangerous-overexposure to radiation.
A better approach taken by Brayer and other clinicians not under spell of “more more more” is to weigh the risks of getting the additional scan with its possible benefits. That often leads clear thinkers, who know that “defensive medicine” (when doctors overprescribe tests in order not to be accused of missing something) is misguided, to address the infection now and repeat the chest X-ray in a few months to see if the unknown spot remains.
Brayer applauds the ability of CT technology, but encourages everyone to understand it better. Her advice:
- If a doctor orders a CT scan for a child, the parent should ask the technician to use pediatric-appropriate settings. (Children are especially vulnerable to the risks of excess radiation.)
- Do not let a doctor or facility repeat a scan that was done recently (for example, if you get second opinions or are seen at a different place). All scans can be electronically shared.
- Ask if a “low-dose” scan is appropriate.
- Avoid using the emergency department for health care-your chances of getting a CT scan for a variety of complaints are extremely high. (See our blog, “Emergency Use of CT Scans Soars.”) The overworked ER doc wants to cover all possibilities, even those that have low probability, in the least amount of time-bingo! Order a CT scan.
- Ask “How could the test result change my (or my child’s care), if at all?”
- Ask, “Can you recommend an alternative, such as an ultrasound or MRI, that doesn’t involve radiation?”
To learn more about radiation overdose injuries, see our backgrounder.