Radiography treatment is used to treat cancer.
Radiography treatment is more commonly known as radiation therapy in the United States. It is the use of radiation as medical treatment, usually for forms of cancer. The therapeutic goal of radiation therapy, also known as radiotherapy, X-ray therapy and irradiation, is to kill cancer cells while doing as little damage as possible to normal cells. Unfortunately, it is never possible to completely avoid damaging normal cells during radiation therapy, so there will also be some degree of toxic effects from treatment.
Use of Radiation Therapy
When the goal of treatment is curative, radiation therapy is often used in combination with surgery and chemotherapy. Depending on the type of cancer, treatment often begins with surgery to remove most of the tumor. That's followed by local radiation to kill off tumor cells that were missed, then chemotherapy to prevent the cells from spreading to other parts of the body. Radiation is also sometimes used to shrink a tumor before surgery and make it easier to remove and in cases where a cure is unlikely to improve patient comfort.
Goals of Radiation Therapy
Radiation kills cells primarily by either damaging their DNA or by creating destructive chemical compounds known as free radicals. Cells that are dividing quickly are more prone to destruction as the result of damaged DNA. Since cancer cells divide more frequently than normal cells, radiation is more likely to damage cancer cells than normal cells. Free radicals are more likely to damage cells that are well-supplied with oxygen. Cells near the edge of a tumor are often well-supplied with oxygen, while cells in the center are not.
Planning Radiation Therapy
A plan for radiation therapy consists of the type of radiation to be employed, the number of sessions per week, the total weeks of treatment and the dose of radiation used per session. Physicians choose to use certain types of radiation depending on the radiation's penetration property and the type of tissue being treated in the patient. The choice of radiation type can have a major effect on how well the treatment kills tumor cells and spares normal cells. Scheduling the treatment in multiple sessions over several weeks helps to ensure that radiation is delivered mainly to the well-oxygenated edge of the tumor where it will be the most effective.
Immediate Toxicity of Radiation Therapy
Since radiation therapy is designed to kill cells, it is inevitable that they will have some degree of toxicity. The short-term toxicity of radiation therapy is seen mostly in cells that are dividing rapidly, such as the skin, the bone marrow (where blood cells are made) and the lining of the intestines. If these tissues are part of the irradiated area, problems such as severe peeling and thinning of the skin, decreased blood cell production and nausea can result.
Long-Term Effects of Radiation Therapy
Since radiation therapy works in part by damaging DNA, it is inevitable that it will to some extent increase the future risk of cancer. Paradoxically, this risk is lower with higher dose radiation, although there does not seem to be a dose high enough to eliminate the risk entirely. The younger a patient is when first exposed to radiation therapy, the more the risk of future cancer seems to increase.
Tags: normal cells, radiation therapy, cancer cells, cells that, dose radiation, edge tumor
