ABSTRACT
PET imaging is based on the coincidence detection of the two 511 keV photons created following the emission of a positron in the decay of a radioisotope and its subsequent annihilation with an electron. As shown in Figure 6.1, a typical PET system capable of performing this function requires (1) a pair of detectors or detector
6.1 Introduction 163
6.2 General PET instrumentation 164
6.2.1 Goal of PET instrumentation 164
6.2.2 Performance considerations 164
6.2.2.1 Spatial resolution 164
6.2.2.2 Detection efficiency 170
6.2.2.3 Timing performance 172
6.3 Detector design for PET imaging 173
6.3.1 Requirements for PET detector performance 173
6.3.2 Detector designs 174
6.3.2.1 Block detector 174
6.3.2.2 Panel-type detectors 176
6.3.2.3 Detectors for preclinical and high-resolution PET systems 176
6.4 Data acquisition in PET 180
6.4.1 Singles event acquisition 181
6.4.1.1 Location of interaction 181
6.4.1.2 Energy deposited in interaction 182
6.4.1.3 Time of event 182
6.4.2 Coincidence identification methods 182
6.4.2.1 Delayed coincidence identification 182
6.5 Data sorting and sinograms 183
6.5.1 Sinogram data organization 183
6.5.2 2D sinogram organization for a cylindrical PET system 183
6.5.3 General 2D sinogram organization 184
6.5.4 3D sinograms 185
6.6 Summary and future directions 188
References 189
rings suitable for detecting 511 keV photons, (2) a data acquisition system capable of digitizing the detector signals, (3) a coincidence sorter to identify pairs of 511 keV photon detection events, (4) a method of binning the data into either sinograms or line of response (LOR) bins, and (5) a method of reconstructing the acquired data into images. In addition to these basic requirements, PET systems require several components, such as a patient bed, sometimes referred to as a patient handling system (PHS), in order to position the patient within the PET gantry for imaging and a method to measure the attenuation map of the object being imaged.
