What are the different types of radiation therapy?

Dr Camille

There two major "types" of Radiation Therapy that can be considered; External Radiation Therapy and Internal Radiation Therapy. There are different subcategories of each "type" of Radiation Therapy of which the overall general description of each will be given.

External Beam Radiation Therapy: In this treatment, the radiation is generated externally, enters the body to the area where it is directed, destroys the cancer cells using this energy (such as photons or protons) and then exits the body. Because the beam is a form of energy, that enters and exits the body, the patient is never radioactive. For "visual animations" of how this works, watch "the basics of Radiation Therapy" in the member section at Internal Radiation Therapy: This type of radiation therapy uses a "radioactive source" that continually gives off Radiation, until it is depleted of its energy (becomes inert). This is often referred to as "Brachytherapy" meaning that the energy only travels a short distance (usually less than 1cm). There are high dose radiation (HDR) where the radioactive source travels along a tube, is exposed to the cancer and destroys it, then is retrieved (this treatment last a matter of minutes; less than 30min depending on the strength/energy of the source). The other type is low dose radiation therapy (LDR) where in most cases the source is left permanently (see animations of permanent prostate seed implant in the prostate section of Another type of LDR used in cervical cancer leaves the radioactive source in for a few days to treat the cancer before removing it. 

Radiation is also used in the "liquid form" to treat some other forms of cancer (thyroid cancer) or used in some test to look for cancer (PET Scan).

Be sure to discuss with the doctor which one of the above type of Radiation Therapy is best suited for the type of cancer being in treated. They will also discuss with you types of precaution that needs to be taken.

External beam radiation therapy is the type most commonly used in oncology. For this type of radiation therapy, you lie on a table and receive a dose of radiation from a linear accelerator, a device that allows radioactive beams to penetrate your body. 3-D conformal radiation therapy is a type of external radiation therapy that allows beams of radiation to penetrate both the inside and the outside of your tumors. Internal radiation therapy uses radioactive implants to deliver radiation directly to the site of your tumor. Radiopharmaceutical drugs also send radiation directly to the site of the tumor.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.