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Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). Although radiotherapy is often used as part of curative therapy, it is occasionally used as a palliative treatment, where cure is not possible and the aim is for symptomatic relief. Other rare uses are to wipe out the immune system prior to transplant to reduce the incidence of tissue rejection, called TBI or Total Body Irradiation; to calm hyperactive muscles -- such as might cause twitchy eyes -- with mild superficial treatments; and to form scar tissue around a stent to reinforce the vascular wall.1 Application
Radiotherapy is commonly used for the treatment of tumours. It may be used as the primary therapy. It is also common to combine radiotherapy with surgery and/or chemotherapy and/or hormone therapy. The most common tumours treated with radiotherapy are breast cancerBreast cancer is cancer of breast tissue. Worldwide, it is the most common form of cancer in females, affecting approximately 10% of all women at some stage of their life in the Western world. Although significant efforts are made to achieve early detecti, prostate cancerProstate cancer is the second most common type of cancer in men in the United States, after skin cancer. Of all the men who are diagnosed with cancer each year, more than one-fourth have prostate cancer. The prostate The prostate is a gland in a man's rep, lung cancerLung cancer is a malignant tumour of the lungs. Most commonly it is bronchogenic carcinoma (about 90%). Lung cancer is the most lethal malignant tumour worldwide, causing up to 3 million deaths. Exposure to carcinogens, such as those present in tobacco sm, colorectal cancerColorectal cancer includes cancerous growths in the colon, rectum, anus, and appendix. It is the third most common form of cancer and the second leading cause of death among cancers in the United States. Many colorectal cancers are thought to arise from p, head & neck cancers, gynaecological tumours , bladder cancer and lymphomaLymphoma is a general term for cancers that develop in the lymphatic system. Hodgkin's disease, discovered by Thomas Hodgkin in 1832, is one type of lymphoma. All other lymphomas are grouped together and are called non-Hodgkin's lymphoma. Prevalence Accor, although the cancer's stageStage has several meanings: In rocketry, a stage is one of several independent rockets used to reduce the need for fuel. Referring to rivers, the stage is the height of the water on a gauge. Flood stage occurs when it begins to overflow the surrounding ar (progress) and invasion into lymph nodes, as well as and other health and (unfortunately) monetary factors affect which treatment will have the greatest possibility of success.
Radiation therapy is commonly applied just to the localised area involved with the tumour. Often the radiation fields also include the draining lymph nodes. It is possible but uncommon to give radiotherapy to the whole body, or entire skin surface.
2 Side effects
Although the actual treatment is painless, using external radiation (see below) to tackle tumours inevitably leads to side effects. The side effects can occur during treatment (acute side effects such as soreness and redness over the affected area; nausea and vomiting) or long after treatment has finished (late side effects reflecting permanent organ damage). Implanting radioactive sources has the usual side effects associated with invasive procedures.
3 Dosage
Radiation Therapy can, to some extent, be regarded as a drug like any other. It is therefore useful to distinguish the total dose from the fractionation schedule. Radiation therapy is usually given daily, the dose depends primarily on tumor type, but many other factors such as whether radiation is given alone or with chemotherapy, before or after surgery, the success of surgery and its findings and many other reasons that are considered by the treating doctor (known as a radiation oncologist). The typical dose for a solid epithelial tumor may range from 50 to 70 Gray or more, while lymphomas (white cell) tumors might receive doses closer to 20 to 40 Gray given in daily doses (a daily dose is a fraction);In adults these are typically ~2 Gy ( Gray (unit)) per fraction. These small frequent doses allow healthy cells time to grow back, repairing damage inflicted by the radiation. In short, total dose can be given in daily fractions using external beam radiation or the total dose can be given via other methods such as implants that deliver radiation continuously over a given timeframe. Depending on the implant type, it may be given as a fraction (e.g. High Dose Rate HDR) over minutes or hours or as another example permanent seeds may be implanted (such as in the prostate) which slowly deliver radiation until the seeds become inactive.
