5.1 Medical Applications
Radiation plays a critical and beneficial role in modern medicine, used for both diagnosing diseases and treating illnesses like cancer.
Diagnostic Imaging
Diagnostic imaging uses radiation to create images of the inside of the body without invasive procedures.
- X-ray and CT Scans: These techniques use X-rays to generate images. X-rays pass through soft tissues but are absorbed by denser materials like bone, creating a contrast image. A CT (Computed Tomography) scan takes multiple X-ray images from different angles to create a detailed, cross-sectional view of the body.
- Nuclear Medicine: This field uses small amounts of radioactive materials, called radiopharmaceuticals, which are introduced into the body. These tracers emit gamma rays that are detected by special cameras to create images of physiological function, helping doctors diagnose diseases at a molecular level (e.g., PET scans, SPECT scans).
Radiotherapy (Therapeutic Applications)
Radiotherapy, or radiation therapy, uses high-energy radiation to kill cancer cells by damaging their DNA. The goal is to destroy the cancer cells while minimizing damage to healthy surrounding tissue.
- External Beam Radiation Therapy (EBRT): A machine, typically a linear accelerator, directs a beam of radiation from outside the body to the tumor. The dose is carefully planned to target the tumor from multiple angles.
- Brachytherapy: A sealed radioactive source is placed directly inside or next to the tumor. This delivers a high dose of radiation to a very localized area, sparing nearby healthy tissues.