Good news for any women with dense breasts (i.e. breast tissue that makes tumors hard to spot on mammograms): A new method may make it much easier to see the inner workings of your boobs.

According to the Associated Press,, molecular breast imaging (MBI) offers a powerful new way to detect cancer in dense breasts. As the AP explains, it uses a radioactive tracer that "'lights up' cancer hiding inside dense breasts." In its first big test against traditional mammograms, MBI revealed more tumors and gave fewer false alarms. It also costs less than an MRI (magnetic resonance imaging, another method for detecting breast cancer).

The AP is quick to point out that MBI would not replace mammograms in women with an average risk of breast cancer. But for women with dense breast tissue -- which is about a quarter of women over 40 -- MBI could be a great new tool. In a test on 940 women with dense breasts and a high risk of breast cancer, MBI found 10 out of the 13 tumors that existed, while mammograms found three and missed 10. Had the two methods been combined, 11 of the 13 tumors would have been detected (the other two tumors were found using different methods).

In MBI, women are given what the AP describes as an "intravenous dose of a short-acting tracer that is absorbed more by abnormal cells than healthy ones. Special cameras collect the 'glow' these cells give off, and doctors look at the picture to spot tumors."

The main downside? At the moment MBI requires women to undergo eight to 10 times more radiation than with a mammogram -- though researchers are working on ways to reduce that with better technology. The next step for MBI is a federally funded study to see how it stacks up next to MRI (which gives a high number of false positives and costs over $1,000).

The bottom line: Don't expect your doctor to use MBI the next time you see her, but stay posted -- as Carrie Hruska, a biomedical engineer at the Mayo Clinic in Rochester, Minn., which has been working on the technique for six years, told the AP, "We're just beginning to see what this technology can do."