Mammography has been a standard screening device for breast cancer since the mid-1970s. And the practice is crediting with a 30 percent decline in death due to early detection and treatment. Now, many doctors are urging women to get a 3-D mammogram, which produces a more detailed view of the breast. But there has not been a large-scale study to determine if the technology actually provides a better outcome… until now. Faith Lapidus reports.