What is the principle of PET scan in nuclear medicine?

The principle of PET scan in nuclear medicine is to detect gamma rays emitted by positron-emitting radiotracers.

PET (Positron Emission Tomography) is a type of nuclear medicine imaging that uses radiotracers to produce images of the body's biological functions. Radiotracers are molecules that are labelled with a positron-emitting radionuclide, such as fluorine-18, carbon-11, or oxygen-15. When injected into the body, the radiotracer travels to the target tissue or organ and emits positrons, which interact with electrons in the surrounding tissue to produce gamma rays.

The gamma rays are detected by a ring of detectors surrounding the patient, which record the location and intensity of the gamma rays. The data from the detectors is then processed by a computer to produce a 3D image of the distribution of the radiotracer in the body. This image can be used to diagnose and monitor a range of diseases, including cancer, neurological disorders, and cardiovascular disease.

PET scans are particularly useful for detecting changes in metabolism and blood flow, as well as the presence of abnormal cells or tissues. They are often used in combination with other imaging techniques, such as CT or MRI, to provide a more comprehensive picture of the body's structure and function. PET scans are non-invasive and have few side effects, making them a safe and effective tool for diagnosing and treating a range of medical conditions.