How Radiation is used in Cancer Treatment

Jack Champlin
James MacLeod

The most common types of radiation used for cancer treatment is high-energy photons, electron beams, protons and neutrons. High-energy photons come from radioactive sources such as cobalt. They penetrate the tissue killing the cancer cells. This is the most common type of radiation treatment in use today. Electron beams, which are produced by linear accelerators, are used for treating tumors close to the body surface because they penetrate less into deeper tissues. A linear accelerator is a device used to create high energy x-rays for radio surgery treatment (webster.com). Protons are a newer form of cancer treatment. They cause little damage to tissues as they pass through, but are very good at killing cells at the end of their path. More people are using this form of treatment because they feel there are fewer side effects due to the fact that the proton is able to deliver more radiation to the cancer. However, proton treatment requires highly specialized equipment and often times the patient is exposed to neutrons, which cause long-term side effects. Neutron treatment is being used less and less today yet it's still used for cancers in the prostate, head and neck areas because of its ability to be highly penetrating and damaging nature to cellular structure.

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Radioactive Isotopes Involved in Cancer Treatment

Iodine - 131 is commonly used in the medical and industrial field. It is used to treat thyroid cancer and is moderately radiotoxic. It is the most successful kind of cancer treatment. The half-life of Iodine - 131 is relatively short. It is a little over eight days and upon radioactive decay it emits beta and gamma particles.

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http://en.wikipedia.org/wiki/Iodine-131

Iridium - 192 is used to treat cancer in the head and breast. They are produced in wire form and are introduced through a catheter to the target area. Iridium - 192 has a somewhat long half-life of about 74 days and it decays with an emission of both beta particles and gamma rays.

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There are also many therapeutic procedures, usually to relieve pain that use rhenium - 186 and strontium - 89. They are used for relief of cancer-induced bone pain and many other things. Rhenium- 186 has a relatively short physical half-life of 3.72 days. It has both beta emissions and gamma emissions suitable for treatment and therapy.

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Strontium - 89 when it decays is a pure beta emitter and has a half-life of 50.5 days.

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The Value of the Particular Application

Radiation therapy can be used to treat almost any type of cancer anywhere in the body. It can be given during any phase of the treatment process depending on the particular disease and goals of treatment. Radiation can be used alone or in combination with other things such as chemotherapy, surgery or other biologic agents to treat cancer. It can be used before and after surgery to shrink and kill the cancer cells.

Risks Associated with the Particular Application

As with any type of treatment or medicine there is always risks involved. Radiation therapy damages cancer cells, but can also damage normal tissue. The damage of normal tissue is what causes side effects. The side effects will vary depending on what part of the body is treated and the dose that that part of the body receives. Common side effects are fatigue, feeling extremely tired, skin problems, loss of appetite, hair loss and decrease in blood count. Radiation can cause the lowering of white blood cells, which can then lead to low immunity to viruses and bacteria because the white blood cells are what fights off these attackers.

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Sources

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Klerk, J.m.h., A. Dijk, A.d. Schip, B.a. Zonnenberg, and P.p. Rijk. "Pharmacokinetics of Rhenium." May 1992. Department of Nuclear Medicine. 23 Jan. 2008 .

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