A fiber optic probe includes a first diffuse reflectance spectroscopy fiber, a second diffuse reflectance spectroscopy fiber, and a temperature sensor at a distal end of a temperature sensor fiber. Other embodiments further include a treatment fiber for delivering a high optical power density of light to a tumor and a dosimetry fiber for monitoring the light flux of the treatment fiber. Other embodiments utilize an image-guidance step in a method of using the fiber optic probe.
