BSc Nursing Final Year, RGU, India
Radiation therapy is also known as Radiotherapy, X-ray therapy or Irradiation. In this therapy, energy called ionizing radiation is used to kill the cancer cells and shrink the tumors. This therapy injures or destroys cells in the areas being treated by damaging genetic material, making it impossible for cancer cells to continue to grow and divide.
Radiation therapy is of two types:
1.External radiation therapy/Teletherapy:
It is administered by a machine at a certain distance from a specific area of the body. The radiation source is external. Depending upon the amount of energy, X-rays can be used to destroy the cancer cells on the surface or in deeper parts of the body. The types of cancer that can be treated are cancer of bladder, brain, breast, cervix, larynx, lungs, prostate, vagina etc. The sources of energy are electromagnetic radiation (X-ray, Gamma rays) and particulate radiation (electrons, neutrons, heavy ions etc.). Some of the specialized methods are Intraoperative radiation therapy, Stereotactic radiosurgery, Stereotactic radiotherapy, 3D conformal radiation therapy, Intensity-modulated radiation therapy (IMRT)
2) Internal radiation therapy/Brachytherapy:
It is a radiation technique in which the specific radio isotopes (radiation source) are placed directly into or near the tumor. The radiation isotopes are usually sealed into a small holder called implant. These implants may be in the form of thin wires or plastic tubes which are placed into the body cavities interstitial compartment. The patient may not be able to have visitors or if any visitors, that too for short period of time because the one with such implants also act like source of radiation. These implants may be temporary or permanent. Once these implants are removed, there is no radioactivity in the body. The amount of radiation should go down to safe level, before patient leaves the hospital.
Methods of treatment of Brachytherapy:
Sealed Brachytherapy and Unsealed Brachytherapy are the two methodologies for the treatment.
a) Sealed Brachytherapy is grouped into interstitial implants and intracavity Brachytherapy. Materials in the form of needle, seed, wire, ribbon, and catheter are inserted into the tissues or near the tumor site in interstitial implants. In Intracavity Brachytherapy, radiation sources are implanted directly into the body cavity and held in place with an applicator.
Image: Brachytherapy seeds used to treat prostate cancer.
b) In Unsealed Brachytherapy, radioactive material such as iodine 131 and strontium 38 are used. These can be taken orally or injected into the body. The substance travels throughout the body and delivers radiation. Profoundly used Radio isotopes are Radium (256Ra), Cesium (173Cs), Cobalt (60Co), Gold (198Au), Iridium (192I), Iodine (131I) Phosphorous (32P) etc. commonly emitting alpha, beta and gamma rays.