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Radiation Therapy: Overview and General Information

Published: 2009-03-24 - Updated: 2022-06-02
Author: Disabled World - Contact Details
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Synopsis: Overview of radiation therapy for both internal and external cancer treatment including types and possible side effects. Radiation therapy or radiotherapy is abbreviated as RT, RTx, or XRT. Nearly two-thirds of all cancer patients will receive radiation therapy during their illness. Radiation therapy may be curative in several types of cancer if they are localized to one area of the body. It may also be used as part of adjuvant therapy, to prevent tumor recurrence after surgery or to remove a primary malignant tumor.

Main Digest

Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is therapy using ionizing radiation, generally as part of cancer treatment to control or kill malignant cells. Radiation therapy may be curative in several types of cancer if they are localized to one area of the body. It may also be used as part of adjuvant therapy, to prevent tumor recurrence after surgery to remove a primary malignant tumor (for example, early stages of breast cancer). Radiation therapy is synergistic with chemotherapy and has been used before, during, and after chemotherapy in susceptible cancers.


Radiation therapy is one of several treatments used in the treatment of cancer, either by itself or in combination with additional types of treatment; most often chemotherapy or surgery. At high doses, several times greater than the amount used for X-rays, radiation is capable of killing cancerous cells and shrinking tumors. More than 50% of all persons with cancer receive some form of radiation therapy as a part of their treatment plan.

Radiation therapy is administered externally, via external beam radiation, or increasingly through internal radiation; also referred to as, 'Brachytherapy.' Recent research is focusing on using special cells within a person's body called, 'Monoclonal Antibodies,' to deliver radiation therapy directly to the site of cancer within them.

Article continues below image.
Color medical illustration of a patient receiving external radiation therapy. External beam radiation therapy comes from a machine that aims radiation at the cancer. Source: National Cancer Institute (NCI) - Creator: NIH Medical Arts.
Color medical illustration of a patient receiving external radiation therapy. External beam radiation therapy comes from a machine that aims radiation at the cancer. Source: National Cancer Institute (NCI) - Creator: NIH Medical Arts.

Use of Radiation Therapy Today

There have been some major advances in Radiation therapy in recent years, largely due to the use of computer technology and highly sophisticated equipment, as well as recent understandings of how cancer cells work. Radiation therapy is safer as a result. Doctors are very careful to limit damages done to healthy tissues by precisely targeting radiation beams directly at cancerous areas. They divide treatments into several smaller sessions called, 'Fractions.' Technicians make sure that radiation therapy equipment is in top working order, and doctors use the minimum effective dose. Patients commonly receive external beam therapy for five days in a row and rest over the weekend. By receiving small, frequent doses and taking brief rests, damage to healthy cells is limited, and destruction of cancer cells is effective.

External and Internal radiation therapies may be used as curative therapies to eliminate cancer. They may also be used as a means of palliative therapy to relieve both pain and symptoms. These forms of radiation therapy can also be used as adjuvant therapies, meaning that they are used in conjunction with additional forms of treatment such as chemotherapy or surgery, hormone therapy, or other treatments.

Adjuvant radiation therapy may be used before surgery to shrink a tumor; also referred to as, 'Neoadjuvant Therapy.' It can also be used with, or after, chemotherapy - making tumors more receptive to radiation therapy. Adjuvant radiation therapy can also be used after surgery to ensure that all cancerous cells are destroyed.

Types of Radiation Therapy


External Beam Therapy is administered much like a common X-ray. Radiation used for external beam radiation treatments comes from machines such as linear accelerators or orthovoltage X-ray machines. These machines deliver treatments with very precise accuracy.

Two additional and common types of radiation used include gamma rays and x-rays. High-energy, penetrating radiation in low doses can be used to diagnose disease, while powerful and penetrating rays may be used in radiation therapy to treat cancer. Both State and Federal guidelines strictly regulate the use of and care of equipment used for these purposes. The patient's safety is always given the highest priority.


Internal Radiation Therapy is a treatment option that involves the placement of radioactive substances such as iridium, cesium, and iodine either near, or into, cancerous cells within a person's body. The person commonly remains in the hospital for at least a day. The implants may be either temporary or permanent. These implants may be placed within a tumor - which is an abnormal growth of tissue resulting from excessive cell division, directly into a cancerous area - called, 'interstitial,' orally, or through an injection.

Cancerous cells reproduce more rapidly than healthy cells in a person's body. Radiation therapy targets cancerous cells; the radiation reacts with the water in the cells, damaging the DNA in the cell that controls the cell's growth. Usually, cells can repair themselves and continue the process of growth. Cancer cells are unable to repair themselves as easily, they tend to die. Although healthy cells are also affected, they repair themselves more efficiently.

Total Body Irradiation

Total Body Irradiation is a form of radiation therapy used in conjunction with a bone marrow transplant.

One single, large dose; or possibly six to eight smaller doses, is administered to the person's entire body to destroy cancerous cells. There is one major disadvantage to this form of treatment; healthy bone marrow is also destroyed in the process. New bone marrow cells that are taken from either the patient or a donor before irradiation are given back to the patient after the treatment. The new bone marrow cells replace the damaged ones and rebuild the person's immune system, helping them to fight infections and diseases.

Use of Internal Radiation Therapy

During Internal Radiation Therapy, a Radiation Oncologist and/or a Surgeon surgically places a radiation source either into or near cancerous cells in the person's body. Placement of a radiation source near the cancer cells makes it possible to deliver a higher total dose of radiation to a smaller area than with external treatment. Through limitation of the amount of radiation that healthy cells are exposed to, the damages done to these healthy cells are minimized.

Internal radiation therapy is being used today to treat persons who have cancers of the prostate, cervix, uterus, thyroid, breast, neck, and head. People may receive both external and internal radiation therapies at the same time, or consecutively. Implants used during internal radiation therapy are also referred to as, 'seeds,' and are a combination of a radioactive source placed within a small holder that is then inserted into the person's body either in or near cancer. During this procedure, the person receives either general anesthesia or a local anesthetic, depending on the location of cancer and the method used to insert the seed.

Implants that are high-dose might be removed after a few minutes, or left in place for a few hours. Implants that are low-dose may be left in place for longer periods; sometimes for a few days, or even permanently. Permanent implants lose their radiation rapidly. Internal radiation may also be administered by injecting a radioactive substance into the person's blood or body cavity, or by mouth.

The type of radiation therapy received depends on many factors, including;

Will I Be Radioactive?

Persons who are receiving internal radiation therapy can emit tiny amounts of radiation for short periods. These persons stay in a hospital in a private room, and the medical professional providing care for them may be unable to spend long periods with them in the room; working quickly.

The person will receive all of the care they need. The person will have limited visiting hours; the person's visitors will be advised of any special precautions.

Possible Side-Effects of Treatment

Persons experiencing radiation therapy commonly endure side effects in the areas that are being treated. Many times, there are ways to treat these symptoms. The side-effects of radiation therapy may include:

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Cite This Page (APA): Disabled World. (2009, March 24). Radiation Therapy: Overview and General Information. Disabled World. Retrieved September 23, 2023 from

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