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.