Every woman over the age of 50 years is urged to have a mammogram to detect signs of early breast cancer - but scientists this week say there is a better and more sensitive test that should be used instead. Mammograms use x-ray technology, so women are exposed to radiation while their breast is being pressed between special plates. As well as being dangerous and invasive, the tests are also notoriously unreliable, often producing false positives and negatives. In other words, they detect cancers that aren't there, so causing unnecessary worry, or they fail to pick up cancers that are there. Instead, hospitals should be using microwave tomography, which is cheaper, less risky and more accurate, say researchers. (Source: SIAM Journal on Applied Mathematics, 2010; 70: 2509-33).