A pipeline backprojector for on-line 3-D PET

A hardware architecture for on-line three dimensional backprojection is considered for positron emission tomography (PET). The architecture is based on processing elements that work in pipeline on a flowing data stream using an event by event approach. The architecture is suitable for backprojection filtering reconstruction where reconstruction requires backprojection first and a subsequent three-dimensional filtering. Although the main target of the architectural design is a VLSI implementation, the modularity of the approach also makes it suitable for an implementation on off the shelf processors. The work takes as reference the complexity requirements of a PET scanner endowed of 24 rings and 784 detectors per ring and a volume of interest subdivided into 128*128*47 voxels. The design of the building blocks of the architecture are described together with their operating mode