Radiation-free cancer scans may be on the horizon

It's been tested on only a handful of kids, but using MRI with a diagnostic dye to look for cancer may work just as well as using PET and CT scans.

This computer illustration shows a tumor in the brain linked to a tumor-killing gel outside the brain.

(Credit: Video screenshot by Michael Franco/CNET)

Using whole-body scans to screen for cancer presents such a catch-22, especially in kids. While traditional radiation scanners like PET and CT are good at finding cancer, they expose patients to radiation that can be harmful and even induce cancer later in life -- more so in younger patients, because their cells are still dividing quickly and because, with more years ahead of them than adults, children also have a higher chance of being exposed to more radiation down the line.

The good news is that scientists have managed to reduce radiation exposure over the past several years without sacrificing image quality. But now there's a potential alternative that involves combining MRI scans with a "contrast agent" that's basically an iron supplement used to differentiate between tissues of different densities, and it appears to be just as good at finding cancer, but without the risks that come with radiation.

Reporting in the journal The Lancet Oncology, researchers from the Children's Hospital of Michigan, the Stanford School of Medicine, and Vanderbilt Children's Hospital say the new MRI approach found 158 tumors in 22 8- to 33-year-olds, compared with 163 found using the traditional PET and CT scan combo.

"If treatment decisions had been made based on either of these scans, the decision would have been the same," lead author Dr. Heike Daldrup-Link, an associate professor of radiology at the Stanford School of Medicine's Lucile Packard Children's Hospital, told HealthDay.

The study is small, but the positive findings are a step toward wider-spread testing to determine the effectiveness and safety of the new method. (Because MRI uses radio waves instead of radiation, the scans themselves have no side effects, so Daldrup-Link says the only real issue is that some patients may be allergic to the contrast agent.)

Next up: study the approach on more kids and investigate how it might work in adults. The researchers say physicians are already launching a study of the technique in at least six major children's hospitals throughout the country.

And because the cost of each method could be roughly the same, if the MRI approach proves just as effective yet safer, radiation-free cancer scans are likely on the horizon.