An odor detector that sniffs for ammonia leaks on the space shuttle could work as a detector for compounds produced by cancer cells. The detector monitors electrical conductivities of polymer films that change in the presence of different substances. In tests, the ENose from NASA correctly diagnosed lung cancer and diabetes in patients who breathed into it, says developer Babak Kateb of City of Hope Medical Center in Duarte, Calif. He and colleagues believe the device could be linked to other brain imaging and mapping equipment to create a high-resolution brain image to pinpoint cancer.

Such a sensor could be useful to surgeons operating in areas where spotting tumor tissue is difficult. Surgeons mostly rely on visual inspection to locate cancerous tissue, referring back to scans taken before surgery. But brain tissue, for one, is hard to distinguish from cancer, and it also changes shape when the skull is opened, so the scans don't match what the surgeon sees.