title: Fully three-dimensional reconstruction for a PET camera with retractable septa.
abstract: A fully 3-D reconstruction algorithm has been developed to reconstruct data from a 16 ring PET camera (a Siemens/CTI 953B) with automatically retractable septa. The tomograph is able to acquire coincidences between any pair of detector rings and septa retraction increases the total system count rate by a factor of 7.8 (including scatter) and 4.7 (scatter subtracted) for a uniform, 20 cm diameter cylinder. The reconstruction algorithm is based on 3-D filtered backprojection, expressed in a form suitable for the multi-angle sinogram data. Sinograms which are not measured due to the truncated cylindrical geometry of the tomograph, but which are required for a spatially invariant response function, are obtained by forward projection. After filtering, the complete set of sinograms is backprojected into a 3-D volume of 128x128x31 voxels using a voxel-driven procedure. The algorithm has been validated with simulation, and tested with both phantom and clinical data from the 953B.
authors.affiliation: Div. of Nucl. Med., Univ. Hospital, Geneva.
authors.forename: D W
authors.initials: DW
authors.lastname: Townsend
authors.forename: A
authors.initials: A
authors.lastname: Geissbuhler
authors.forename: M
authors.initials: M
authors.lastname: Defrise
authors.forename: E J
authors.initials: EJ
authors.lastname: Hoffman
authors.forename: T J
authors.initials: TJ
authors.lastname: Spinks
authors.forename: D L
authors.initials: DL
authors.lastname: Bailey
authors.forename: M C
authors.initials: MC
authors.lastname: Gilardi
authors.forename: T
authors.initials: T
authors.lastname: Jones