Implementation of spiral PET on cameras with rotating planar detectors

Whole-body PET scanning is achieved by using couch movement to extend the field of view beyond the axial length of the detectors. For PET cameras with rotating planar detectors whole-body scanning can be achieved via spiral PET i.e. by simultaneous and continuous couch translation and gantry rotation. Higher SNRs are obtained when continuous couch motion is used compared with the more conventional step-and-shoot methods of whole-body PET acquisition. The large axial extent of PET cameras with rotating planar detectors and their inherent 3D geometry make these cameras ideally suited to continuous sampling and a spiral mode of acquisition for wholebody imaging. Hardware and software have been developed for list-mode spiral PET acquisition using the PETRRA camera. Image reconstruction is based on backprojection and filtering techniques. Previous optimization of the image reconstruction method and parameters using the MUP-PET camera has been adapted to account for the different geometries of the two cameras. To achieve accurate quantification, the data need to be corrected for non-uniform sampling (by application of both rotational and longitudinal weights), as well as for camera nonuniformity, randoms, deadtime, attenuation and scatter. High-quality whole-body images have been produced of phantom data acquired with short scanning times under ideal conditions of minimal scatter and randoms. Image quantification is still to be achieved on PETRRA via implementation of corrections for scatter and randoms. Spiral PET, as implemented on PETRRA, could be applied to gamma-camera PET systems, provided they offer continuous gantry rotation, couch translation and list-mode data acquisition.