A rebinning technique for 3D reconstruction of Compton camera data

A newly developed 3D image reconstruction technique for Compton cameras is described. For Compton cameras, the energies and positions of gamma-ray interactions in two detector systems from a single incident photon are recorded using coincidence techniques. Based on this information, the Compton scattering formula establishes a cone surface from which the incident photon must have originated. Instead of projecting the entire cone surface into the image space as is typically done, a number of lines on the cone surface are sampled. All the lines start from the apex of the cone and are evenly distributed over the cone surface. The number of lines on each cone is determined by the desired spatial resolution. A series of imaginary planes are then constructed such that all solid angles (4pi) that the Compton camera system holds. Each line is then projected to one plane that is mostly perpendicular to this line. The imaginary planes are predefined and grouped into a number of groups with each group having all its planes rotating along one axis. Each group of planes can be treated as the standard SPECT projection data set and one image can be reconstructed using filtered backprojection algorithm. Each group of planes can reconstruct one low statistical image with its specific orientation. Rotating and summing all the images together give the final image.