There's a well-established medical technology that many physicians believe could help catch undiagnosed breast tumors in one-third to one-half of women -- yet it's not being used routinely. It's ultrasound imaging, a longtime fixture of obstetricians' offices. Some doctors use ultrasound along with traditional x-ray mammography in breast exams, but the majority have been waiting for clearer evidence of its benefits. And that's exactly what a key clinical trial now under way in the United States could provide.

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