A radiation oncologist is a doctor who specializes in radiation therapy for cancer patients. This is a subspecialty of medical oncology and radiology. Radiation is sometimes used to treat mesothelioma in conjunction with chemotherapy and/or surgery. Radiation is also used as a palliative treatment to help relieve pain or other symptoms. If you choose to undergo radiation, your doctor may refer you to a radiation specialist. After you have completed your course of radiation therapy, the radiation specialist will refer you back to your medical oncologist, who is the “leader” of your medical team.