May 7, 2007 Almost every doctor’s surgery in a developed country has a 2-D ultrasound scanner and for most parents it’s the first time they see their child-to-be. Apart from enabling us to see an unborn child in its mother’s womb, medical ultrasonography helps to detect gall stones, identify tumor-like lumps and it plays a particularly important role in the early detection of breast cancer. Three-dimensional sonography can provide especially informative images, for instance allowing the structure of tumors, their growth pattern and their blood supply to be clearly distinguished from healthy tissue. Although 3-D technology has been available since the 1990s, it remains prohibitively expensive. Physicians and clinics wishing to upgrade from 2-D to 3-D technology usually have to invest more than US$100,000 in new equipment. Now researchers have produced a system that enables conventional 2-D ultrasound scanners to be upgraded to provide 3-D images for less than US$1000.