A system for optical tomography includes an apparent light source adapted to project excitation light toward a specimen having fluorescent proteins therein, wherein the excitation light enters the specimen becoming intrinsic light within the specimen, wherein the intrinsic light is adapted to excite fluorescent light from the fluorescent proteins, and wherein the intrinsic light and the fluorescent light are diffuse. A method of optical tomography includes generating the excitation light with the apparent light source, wherein the intrinsic light and the fluorescent light are diffuse.