At this point, people believe there is [a] linear relationship between the dose and the risk of cancer. So if you cut the dose in half, you also cut the risk in half. The question should be, can you optimize the dose by using a lower amount of radiation or can the scan be done only once instead of three times? For kids especially, doctors should really optimize with the lowest dose possible if a CT scan is warranted.
Is that happening?
I would say that five or so years ago, there's no question they were actually getting adult doses. But after Dave Brenner [of Columbia] started hopping up and down about this problem and it was picked up in the media, pediatricians got very sensitive and manufacturers began putting pediatric dose settings on the CT machines. But, I don't think the sensitivity is there for teenagers or young adults.
What are some alternatives to CT scanning that patients should know about or ask their doctors?
I would ask if there are ways we can find out the answer without using radiation. Using ultrasound, for example, or doing an MRI scan. Those don't use ionizing radiation, so there is virtually no risk. And if the scan is definitely going to be done, ask about the dose you will be getting. If a child is getting a scan, a concerned parent should make sure the radiology technician is using the correct pediatric doses.
How do you prevent redundant CT scans and help patients to keep track of the scans they've already had?
When our patients go to another hospital or doctor, we give them a CD of all their exams on it, and anyone can open them up, throw it on a PC, and have a look at the pics. That's very helpful.
Are CT scans useful for asymptomatic patients?
I don't recommend CT scans for asymptomatic patients. Take lung cancer screening for example. One article in the New England Journal of Medicine from last year concluded that CT scanning could prevent 80 percent of lung cancer deaths by catching lung nodules. Then in a 2007 Journal of the American Medical Association study, there was found to be no reduction in mortality by using CT scans for lung cancer. We shouldn't do something with risk until studies determine what the risks and benefits actually are. A lot of scans are not justified, like the business of whole-body CT screening. No one has ever shown that these have more benefit than risk.
