The present disclosure provides a method and a system for treating a tissue using photodynamic therapy (PDT). A photosensitizer is administered to the tissue and one or more optical fibers are placed in the tissue. A treatment light is applied to the tissue by way of the one or more optical fibers. A temperature of the tissue is measured during application of the treatment light, and a fluence rate of the treatment light is modified based on the temperature of the tissue. For example, the fluence rate may be modified to be lower if the temperature of the tissue is higher than a predetermined threshold.)
