One of the effects that ionizing radiation has on the human body is the appearance of cancer. To treat cancer, ironically, radiation is often used. Radiation treatment is the 2nd most common form of cancer treatment, next to surgery. The National Cancer Institute estimates that over half of all cancer patients receive radiation treatment sometime over the course of their illness (Radiation Therapy and You 2). It can be used alone to fight cancer or can be used in combination with surgery or chemotherapy.
Radiation therapy is not usually administered by a normal physician, but rather by a radiation therapist, more commonly known as a radiation oncologist. Radiation treatment is also known as : radiotherapy, radiology, x-ray therapy, irradiation, or cobalt treatment. What is Radiation Therapy? Radiation treatment consists of using x-rays at high levels (tens of thousands of times the amount used to produce the average chest x-ray) to destroy the cell’s ability to grow and divide. (ONCOLOGY lit. ) Both cancer cells and normal cells are affected, although the normal cells recover more quickly.
Radiation therapy is used to fight radiosensitive cancer. Radiosensitive cancer is cancer that is susceptible to destruction by radiation. On the other hand, some cancers are radioresistant and cannot be treated with radiation within the safe dose range. There are two major methods of radiation treatment: 1/ Internal Radiation (a. k. a. radium implant, brachytherapy, or interstitual or intracavitary radiation) In this procedure the radiation oncologist places radioactive material (usually radium, cesium, or iridium), into or onto the inflicted area.
The purpose is to place the radioactive material as close to the tumor as possible. This can be done in two ways: (i) The radioactive materials are put in a sealed container, such as a tube or needle, and is placed (usually surgically) within or near the cancerous tissue. The tubes or needles are removed after the required dose has been administered. For example, a sealed tube containing radioactive cesium can be inserted into the vagina, radium needles can be implanted into the tongue or breast, and radium seeds can be used for prostate cancer.
Some radioactive substances cannot penetrate casings, so they are used unsealed. Liquids can be injected into the abdomen or the lung cavities. In these liquids are particles that stay in one place; they do not readily pass into blood and lymph. (ii) The radioactive materials are given orally or injected with a syringe. The materials mix with body fluids, and are transported to the internal parts of the body. For example, radioactive iodine is swallowed, and finds its way to the thyroid gland to attack a tumor there (ONCOLOGY lit.)
Liquid radioactive gold or phosphorus can be injected directly into the area of a tumor. 2/ External-beam Radiation In this procedure, a machine directs x-rays or gamma rays to a tumor in the body. This is used much more frequently than internal radiation. There are several types of machines used, but usually either a linear accelerator or a cobalt machine is used. Both machines use high-energy beams to destroy tumor tissue. Both are usually referred to as x-ray machines, but different energy sources produce the beams in each case.
The linear accelerator produces electromagnetic waves. The machine must be turned on to change electricity into the high-energy beams. Cobalt machines use the radioactive isotope of cobalt. The rays are beamed to the body from the source. The radioactive material is enclosed in a shielded unit, and the beams are emitted through a shutter. The cobalt machine does not have to be turned on. In both machines, the distance the beams penetrate depends on the speed at which particles hit the target.
To ensure that the procedure is safe, all machines are shielded so the radiation is only applied to the necessary area. Lead casts and blocks and even plastic molds are custom made for the patient and are used to protect vital organs and to maintain the proper treatment position throughout the entire course of the therapy. Treatment is given in intervals to allow time for normal cells to heal. The radiation therapist calculates the total dosage necessary, and divides it into several doses, usually at five treatments a week.
Each treatment session only takes a few minutes. The treatment schedule often changes throughout the treatment as progress is made.
SIDE EFFECTS : Side effects are common with radiation therapy. The extent of the side effects range from none to slight to severe in patients, depending on the intensity of the treatment. Some side effects are: dry or itchy skin, hair loss, extreme fatigue, sluggish bowels, sore throat, dry cough, earaches, nausea, vomitting, and diarrhea. (ONCOLOGY lit. )