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Positron emission tomography (PET)

are a type of medical imaging that use a small amount of radioactive material to produce images of the body's internal organs and tissues. Here's a more detailed explanation of how PET scans work:

1. Injection of Radioactive Material: Before undergoing a PET scan, the patient will be injected with a small amount of a radioactive substance, known as a radiotracer. This radiotracer is typically a form of glucose that has been labeled with a radioactive molecule, such as fluorine-18.

2. Uptake of Radiotracer: Once the radiotracer has been injected, it will circulate through the body and be taken up by the organs and tissues being imaged. The radiotracer is similar to glucose and is taken up by cells that require glucose for energy.

3. Emission of Positrons: When the radiotracer is taken up by the body's cells, it emits positrons, which are positively charged particles. The positrons travel a short distance through the body's tissues before colliding with electrons.

4. Production of Gamma Rays: When the positrons collide with electrons, they produce gamma rays, which are a form of electromagnetic radiation. The gamma rays are emitted in opposite directions and are detected by a ring of detectors that surround the body part being imaged.

5. Image Reconstruction: As the detectors detect the gamma rays, they send signals to a computer, which uses mathematical algorithms to reconstruct an image of the body's internal organs and tissues. The image is created by assigning different colors or shades of gray to the different levels of radioactivity detected by the detectors.

6. Image Analysis: The resulting image can be analyzed by a radiologist or other medical professional to diagnose a range of conditions, including cancer, neurological disorders, and cardiovascular disease.

In summary, PET scans work by injecting a small amount of a radioactive substance into the body, which emits positrons that collide with electrons and produce gamma rays. These gamma rays are detected by a ring of detectors and used to create an image of the body's internal organs and tissues. PET scans are a non-invasive and painless imaging technique that are widely used in medical diagnosis and research.