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Radiation Therapy Overview

Radiation oncology or radiation therapy is the treatment of cancer and other diseases with radiation. Oncology is the branch of medicine concerned with the diagnosis and treatment of cancer. Radiation in many forms is used to kill the cancer cells by preventing them from multiplying. Radiation therapy may be used to cure or control cancer. Or, it may be used to ease some of the symptoms associated with cancer.

Health care providers who treat diseases with radiation therapy are called radiation oncologists.

Radiation therapy was developed just a few years after the discovery of X-rays in 1895 and the discovery of radium in 1898. The first cure of cancer by radiation was reported in 1899. This involved a case of skin cancer. Radiation oncology became recognized as a medical specialty in 1922. 

Radiation therapy treatment may be used alone, or in conjunction with other types of treatment, like surgery, chemotherapy (the use of anticancer drugs to treat cancerous cells), and/or other treatments.

The level and type of radiation used will be decided by the radiation oncologist based on the type of cancer, location of the tumor, and sensitivity of the surrounding tissue.

Although each facility may have specific practices in place, generally, radiation oncology procedures include these steps:


  • Simulation. To help set up the actual treatment, the treatment team first "maps" out the position the patient will be in for each treatment. This is done with the aid of molds, headrests, or other devices. Sometimes, the area on the body to be treated will be marked to make sure the radiation will be given in the exact area. In addition, special shields may be made to help focus the radiation and protect surrounding tissue.

  • Treatment plan. Once the simulation has taken place, the radiation oncologist will decide the exact type of treatment.


Radiation Oncology Team

Radiation oncologists collaborate with a comprehensive team of medical oncologists, surgeons, nurses, radiation therapists, medical physicists and dosimetrists, some of which are defined below:

Radiation Oncologist
Radiation oncologists are specialist physicians who use radiation to treat cancer and prevent the spread of the disease. Radiation can be used alone or combined with surgery and/or chemotherapy. Your radiation oncologist will collaborate with other specialists as part of a multidisciplinary team for the best treatment outcomes.

Medical Oncologist
Medical oncology is the use of medications to treat cancer and prevent the spread of the disease. A medical oncologist will coordinate and oversee your cancer care and treatment, which may include chemotherapy, infusion services (such as hydration), hormones and/or pain management.

Fellow (Oncology)
A physician who has completed medical training and is continuing training in oncology.

A physician who has received a MD degree and is training in oncology and working under the supervision of an attending physician.

The medical dosimetrist works closely with the medical physicist and radiation oncologist. The dosimetrist uses advanced computer systems to generate treatment plans using their knowledge of radiation oncology technology, physics, anatomy and radiobiology. Their expertise ensures the treatment plan employs the correct dosage of radiation to reach the targeted tissues while protecting healthy tissue.

Radiation Therapist
Radiation therapists specialize in administering doses of radiation to treat cancer according to the treatment plan provided by the dosimetrist and radiation oncologist. The radiation can be delivered in various forms and methods to help to shrink the tumor.

Medical Physicist
Medical physicists help ensure the safe and accurate use of radiation therapy. They set guidelines for radiation procedures, ensure safe and accurate measurement of radiation doses and monitor the radiological equipment. Their role may also include research and development of new technologies. A qualified medical physicist may have a master's or doctorate degree with 1 to 2 years of clinical physics experience. Medical physicists are certified by the American Board of Radiology or the American Board of Medical Physics.

Radiation Oncology Nurse
A nurse who specializes in radiation oncology. They evaluate patient progress and explain the management of possible side effects of treatment. These nurses ensure the continuity of care, consider a patient’s individual needs and serve as a communication link between doctors and other health care professionals involved in care and treatment.

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