How do PET scans work?

A radioactive isotope is introduced in the patient's body, at first. This isotope (mainly fluorine added to glucose) emits a positron (the antiparticle of the electron) via beta positive decay in the vicinity of the target organs or body region. When the positron meets an electron, two opposite photons are emited from the annihilation place. The gammacamaras will detect these photons and sophisticated computational algorithms will place the region of interest with precision.