The radiation therapist is in daily contact with the cancer patient, positioning them for treatment, performing mathematical calculations of radiation dosage and operating a variety of equipment that produces ionizing radiation. Therapists may also specialize in the area of treatment planning, which includes design and construction of various treatment devices, manual and computerized dose computations and dose measurement procedures. The radiation therapist has considerable responsibility in the area of patient care and must be knowledgeable regarding the psychology of dealing with terminally ill patients and their families.