Q.Explain the principle involved in PET scan

Positron emission tomography (PET) is a nuclear-medicine imaging technique that, unlike CT, images function rather than only structure, by measuring positron emission from a radiolabelled tracer. PET uses positron-emitting radioisotopes (such as 11C, 13N, 15O, 18F) produced in a cyclotron, most commonly 18F-fluorodeoxyglucose (18F-FDG), a radiolabelled glucose analogue incorporated into biological molecules and injected in tiny amounts. Powerful PET cameras detect the three-dimensional distribution of the tracer as it decays, and a computer …