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The journal of the American Medical Association found that nearly a quarter of the women who got a lumpectomy went back for more surgery. But as Elaine Quijano reports, a study found those extra procedures may be unnecessary.

Japan's Fukushima Daiichi nuclear reactor accident has focused new attention on how much ionizing radiation people are exposed to from different sources (see list below). By far the largest source is medical imaging technology (see " Graphic Science: Exposed " in the May 2011 issue). Americans, on average, are exposed to 3.1 millisieverts of radiation a year from natural background factors such as radon gas from the Earth and cosmic rays from the universe