Three Dimensional (3-D) Reconstruction With Cone Beam Geometry Applied To Nuclear Medicine Imaging

A convolution-backprojection algorithm for fully 3-D reconstruction from cone beam projections was developed and implemented on an ADAC 3300 nuclear medicine computer system interfaced to a rotating scintillation camera with a pinhole collimator. As an approxima-tion, a space-invariant filter was applied to each projection independently before back-projection. The resolution of the system was found to be 7.8 mm at the center of field of view and 10.5 mm in the periphery, as opposed to 18 mm for a parallel hole, all purpose collimator. Results with phantom studies demonstrated that the technique provided images with improved spatial resolution.