A tomographic fluorescent imaging device for imaging fluorophores in biological tissues has a scanned laser for scanning the tissue and a camera for receiving light from the biological tissue at an angle to the beam at a second wavelength ten or more nanometers greater in wavelength than the wavelength of the laser. Use of both intrinsic and extrinsic fluorophores is described. Images are obtained at each of several positions of the beam. An image processing system receives the series of images, models a path of the beam through the tissue, and determines depth of fluorophore in tissue from intersections of the modeled path of the beam and the path of the received light. The laser is of 600 nm or longer wavelength, to provide penetration of tissue. The imaging device is used during surgery to visualize lesions of various types to ensure complete removal of malignant tumors. An alternative embodiment uses differences in intensity of fluorescent radiation from tissue as observed at different wavelengths to determine depth of fluorophore in tissue. An embodiment operates at multiple wavelengths to construct tomographic images of chromophores, such as hemoglobin, and is capable of dynamic imaging.