What percentage of all events in 3D PET imaging are scatter events?

In 3D PET imaging, the percentage of all events that are classified as scatter events is significant and is indeed estimated to fall between 40% and 60%. This high proportion is largely due to the nature of the imaging process itself. In 3D PET, the emitted positrons from radioisotopes interact with matter, primarily in the form of scattering that occurs within the patient's body and in the PET scanner itself. This scattered radiation can lead to events that are detected by the scanner but do not originate from the true annihilation events that the imaging seeks to capture.

The accuracy of PET imaging can be impacted by the presence of these scatter events, making scatter correction techniques critical in the processing of PET data to improve image quality and quantitative accuracy. Understanding this percentage is essential for interpreting PET scan results and for optimizing imaging protocols to reduce the influence of scatter on the images produced.