How does radiation therapy work? Well, high energy radiation displaces electron from atoms and molecules. This 'high energy' radiation is …show more content…
Electrons as depicted have a short range and are used when cancer cells are close to the skin. Both types of x-rays and gamma rays penetrate deeper than electrons, however the dose absorbed by the tissue decreases exponentially. For protons, as the depth increase so does the absorption. Unlike other types of particles, the peak for protons is very steep and only for a certain exact depth. The advantage of this pattern in energy deposition is that minimal energy is affecting healthy tissues as opposed to the malignant cancer tissue.
Brachytherapy
Unlike the methods described above, brachytherapy is know as internal radiation therapy. Like the same suggests, brachytherapy is a form of therapy where a radiation source is directly placed inside, or near a tumour. One may use this method of treatment as the radiation has to travel a shorter distance, thus reducing the chance of damaging normal healthy tissue. This method also deals a large amount of radiation to a concentrated area in a short period of time. There are two main types of internal radiation:
Interstitial radiation - Radiation source is placed directly into or next to neoplasm as a small pellets or …show more content…
Based on the type of brachytherapy needed, various types of radioactive material are used. The most commonly used radiation sources that release energy by beta-minus decay are Cesium-137, Cobalt-60, Ruthenium-106, and Radium-226. Also, while decaying Iridium-192 releases gamma rays, that can be used for radiation therapy. Other radionuclides used are Cesium-131, Iodine-125, and Palladium-103. What is unique about these radiation sources is that they encounter electron capture. During electron capture, an element from the atom’s inner shell get captured into the nucleus. To fill the place of the captured electron, an electron from a higher energy level drops down and releases a photon of light in the form of x-rays and gamma rays. In the nucleus, the electron combines with a proton resulting in a neutron and electron neutrino. Since a proton has become a neutron, a transmutation has