Doctors have relied on x-ray technology for more than a century to diagnose a range of ailments, from broken bones to tumors. Though it is still an indispensable tool, many physicians remain leery of the potential damage the energetic beams can cause to DNA -- posing a slight risk of cancer. Recently, researchers have turned to infrared light, which passes through cells without causing damage, as a potential replacement. The problem with IR imaging is finding a way to compose an image from the few IR photons that pass directly through tissue without getting scattered. In a new development, a team from the University of Arizona in Tucson and the California Institute of Technology in Pasadena has found a light-sensitive polymer that might do the job. The result is a hologram, from which a three-dimensional image can be constructed. The polymer, DHADC-MPN, can change its optical properties in response to the interference between the few IR photons traveling straight through a scattering medium and a separate IR beam. The result is a hologram, from which a three-dimensional image can be constructed. So far, systems based on the polymer have been successful imaging only small slices of tissues.