Physics of PET and Respiratory Gating

Positron emission tomography (PET) is an imaging technique that detects radiolabelled drugs, which have been injected into the body. PET uses radioisotopes which emit energy in the form of positrons (β+). As the positron interacts with the surrounding tissue, it subsequently forms two gamma rays (γ) of equal energy (511 keV) in opposite directions. These gamma rays can then be detected by external detectors and used to produce a 3D image. A number of corrections are applied to improve image quality and respiratory gating methods can be used to correct for respiratory motion. Hybrid imaging also allows fused data for anatomical localisation and attenuation correction.