Optical biopsy hunts would-be cancers

The difference between slightly abnormal tissue and precancerous tissue can be subtle. Because the changeover may not be visible to the naked eye, surgeons exploring questionable tissue remove a tiny sample for a biopsy–a detailed examination by a trained pathologist. If some biomedical researchers have it their way, physicians will one day be able to scout for precancerous cells by simply shining light on them.