In scintimammography, a radioactive tracer is injected into the patient, then a special camera locates where the radiation accumulates in the breasts. It is not used as a screening test but has proved a useful complement to mammography in diagnosing cancers when they're large enough. Some studies suggest that a newly developed "high resolution dedicated breast camera" may be useful with smaller cancers too.
A note of caution: Although some of these new technologies are already in use and others are in clinical trials, most probably won't be coming to a clinic near you very soon. And none of them offers hope for solving one big screening dilemma: how to distinguish dangerous cancers from those that will never go on to threaten a woman's life or cause her any problems at all. Because scientists can't do this yet, they generally treat all cancers, often with toxic chemicals or radiation.
Nonetheless, breast cancer screening has been shown to save lives, and scientists around the world are working to make it do an even better job. "This is a very active field of research," Sheth says. "We keep learning more every day."