Components of a PET camera
The figure shows the components of a PET camera. In this example, we find at the elementary level, 8 x 8 crystals scintillators viewed by 4 photomultipliers, the whole forming a detection block. 72 of these blocks are assembled into a ring. The final set-up, made of 4 rings, surrounds the bed on which the patient will lie. It can move along the axis of the bed. Thanks to these 4 rings, measurements will be taken simultaneously from various angles. This allows the reconstruction of 3D maps of radioactive tracers in the body, while reducing the exposure to radiations. The spatial resolution, ie the precision of reconstruction, is about 5 mm.
A.Aurengo/ Hôpital Pitié-Salpêtrière (Image Siemens)