PET imaging, or positron emission tomography imaging, is a medical imaging technique that allows visualization of the metabolic activity in the body. It involves the injection of a radioactive tracer into the body, which emits positrons that can be detected by the scanner. The images produced by PET scans provide valuable information about the functioning of organs and tissues, as well as the presence of diseases such as cancer and neurological disorders. PET imaging is commonly used in oncology, cardiology, and neurology for diagnosis, monitoring treatment response, and research purposes.