# 22.8 Medical Uses of Radiations Radiation is one of the most powerful tools in modern medicine. Doctors use it in two main ways: to diagnose problems by seeing inside the body, and to treat diseases such as cancer. This section introduces key technologies including diagnostic X-rays, , , and gamma ray therapy. ## Medical Applications of Radiation Radiation has extensive applications in both medical treatment and diagnostics. These applications are generally categorized into diagnostic techniques (finding the problem) and therapeutic techniques (treating the problem). **Commonly used radiations:** - **Medical X-rays**: Widely used for diagnostic imaging of bones and dense tissues. - **Gamma ray therapy**: High-energy photons used to destroy cancerous cells. **Commonly used diagnostic techniques:** - **Medical tracer**: A radioactive substance (radioisotope) injected or swallowed to monitor the function of specific organs. For example, Iodine-131 is used to study the thyroid gland. - **PET scanner**: A powerful diagnostic imaging tool that detects positron emission to create 3D images of metabolic activity in the body. ### Radiotherapy and Sterilization In addition to imaging, radiation is used for treatment (Radiotherapy) and safety (Sterilization). * **Radiotherapy**: Concentrated beams of gamma radiation, often from a Cobalt-60 source, are aimed at tumors. The ionizing radiation damages the DNA of cancer cells, preventing them from dividing. * **Brachytherapy**: A form of radiotherapy where a sealed radiation source is placed inside or next to the area requiring treatment. * **Sterilization**: Gamma rays are used to kill bacteria and viruses on medical instruments like scalpels and syringes, ensuring they are safe for surgery without using heat that might damage plastic components.