Investigation of 3D SPECT Reconstruction with Multi-energy Photon Emitters

Abstract

Parallel projection based Single Emission Computed Tomography is a widely used nuclear imaging technique. Non-homogeneous attenuation medium and the distance dependent spacial resolution (DDSR) of the parallel imaging cause serious artefacts during image reconstruction. Both effects are dependent on the energy of gamma photons used for imaging. In this paper an efficient parallel reconstruction algorithm is introduced that is executed on the Graphics Processing Unit. The aim of the presented study was to investigate the possibilities of reconstruction techniques when multi-energy photon emitters are used. An analytical 3D projector with attenuation and detector response modelling was used to generate projection sets for Gallium-67 isotope studies. Data were reconstructed from one photopeak only using the corresponding attenuation map. The projection data sets were added together and reconstructed using average attenuation and DDSR compensation values as well as simulating every photopeak individually. The third combined reconstruction technique was using every projection set as separate measurement. In this study we showed that all three strategies result in similar image quality, however the average attenuation correction method is computationally less demanding.