Radiation Therapy
Radiation therapy is the use of a certain type of energy to shrink tumors and kill cancer cells. It destroys cells or injures in the area being treated by damaging their genetic material, making it impossible for these cells to continue to divide and grow. Although radiation damages both normal cells and cancer cells . The most normal cells can recover from the effects of function and radiation properly. The goal of radiation therapy is to damage as many cancer cells as possible, while limiting harm to nearby healthy tissue.
There are three types of radiotherapy-
- External beam radiotherapy (EBRT or XRT) or teletherapy
- Conventional external beam radiotherapy
- Stereotactic Radiation
- Virtual simulation, 3-dimensional conformal radiotherapy, and intensity-modulated radiotherapy
- Particle Therapy
- Brachytherapy or sealed source radiotherapy
- Radioisotope Therapy (RIT) or unsealed source radiotherapy
External beam radiotherapy
It is the most frequently used form of radiotherapy. The patient sits or lies on a couch and an external source of radiation is pointed at a particular part of the body.
- external beam radiotherapy directs the radiation at the tumour from outside the body.
- Kilovoltage x-rays are used for treating superficial structures and skin cancer.
- Megavoltage X-rays are used to treat deep-seated tumours (e.g. bladder, bowel, prostate, lung, brain).
Brachytherapy or Internal radiation therapy
This therapy is used to place radiation very much close or inside the tumor. the source are usually implant, they may be in the form of thin plastic tubes, wires called seeds,catheters, capsuled, ribbons. Internal radiation therapy is being used to treat cancers of the head and neck, breast, uterus, thyroid, cervix, and prostate. Patients can receive both internal and external radiation therapy at the same time or consecutively.
Systemic radiation therapy
In this therapy, the radiation source is given by injecting in to vain or as a liquid. Radioactive materials such as iodine 131 and strontium 89 are used in it. You can not feel the radiation travelling throughout body.The therapy itself isn’t painful. Systemic radiation therapy is sometimes used to treat cancer of the thyroid and adult non-hodgkin lymphoma.
External beam radiotherapy (EBRT or XRT) , Brachytherapy, Radioisotope Therapy (RIT) can deep penetrate into the body than can others. In addition, some types of radiation can be very finely controlled to treat only a small area without damaging nearby organs and tissues. Other types of radiation are better for treating larger areas.
In some cases, the goal of radiation treatment is the complete destruction of an entire tumor. In some other cases. the aim is to relieve symptoms and shrink a tumor . In either case, doctors plan treatment to spare as much healthy tissue as possible.
About half of all cancer patients receive some type of radiation therapy. This therapy may be used alone or in combination with other cancer treatments, such as surgery or chemotherapy. In some cases, a patient may receive more than one type of radiation therapy