Photodynamic Therapy (sometimes referred to as Blue Light Therapy) is used to help decrease the number of pre-cancers called Actinic Keratosis in an area. is a treatment that uses special drugs, sometimes called photosensitizing agents, along with light to kill cancer cells. The drugs only work after they have been activated or turned on by certain kinds of light. PDT may also be called photoradiation therapy, phototherapy, or photochemotherapy. For more information, visit coloradodermatologyinstitute.com