A drug called Photofrin is injected into the patient's bloodstream. Photofrin attaches to the unwanted tissues and seeps into them, leaving the surrounding tissues untouched. Dr. Whelan then uses a new solid-state LED probe to illuminate the tumor, activating the Photofrin. This results in the generation of free radicals in the cancer cells, causing them to die. Photofrin is currently approved in the United Sates for the treatment of certain lung and esophageal cancers.
Lasers are also very expensive and lose power in their fiberoptic cables.
Because of these problems, Dr. Whelan has Food and Drug Administration approval to use the LED probe in the removal of children s brain tumors on a trial basis. The LED light shines through all nearby tissues, reaching parts of the tumor that the shorter wavelengths of laser light cannot. The new probe is also safer because the longer wavelengths of light are cooler than the shorter wavelengths of laser light, making the LED less likely to injure normal brain tissue near the tumor. Since the LED unit can be purchased for a fraction of the cost of a laser, this work has helped reduce the cost of treatment while making it more effective. In addition, the LED's seem to be able to stimulate the growth of tissues to aid in the healing of wounds, another effect being researched.