PT - JOURNAL ARTICLE AU - Benjamin Tsui AU - Jianhua Yu AU - Jingyan Xu AU - Bing Lian AU - James Hugg TI - Image reconstruction methods for a novel dual-pair multipinhole collimator set with improved small animal SPECT system performance DP - 2011 May 01 TA - Journal of Nuclear Medicine PG - 264--264 VI - 52 IP - supplement 1 4099 - http://jnm.snmjournals.org/content/52/supplement_1/264.short 4100 - http://jnm.snmjournals.org/content/52/supplement_1/264.full SO - J Nucl Med2011 May 01; 52 AB - 264 Objectives To develop and evaluate image reconstruction methods for a novel dual-pair multipinhole collimator (MPHC) set for use with a 4-head small animal (SA) SPECT system with improved imaging performance. Methods The novel collimator set consisted of 2 pairs of 2 identical MPHCs. The MPHC in the 1st pair has 5 pinholes, shorter focal length (FL) and non-overlapping pinhole projections and the 2nd pair has 5 pinholes, longer FL and overlapping projections to allow higher resolution. In the first step of the new dual-step OS-EM reconstruction method, a 3D MPH OS-EM was applied to the non-overlapping projections from the 1st MPHC pair to generate artifact-free reconstructed images. The reconstructed image from a carefully selected number of updates was used as the initial estimate in the second step where the 3D MPH OS-EM was applied to the overlapping projections from the 2nd MPHC pair. The reconstruction method was evaluated in simulation studies using digital phantoms with various lesion sizes and contrasts and a digital mouse whole-body (MOBY) phantom modeling a 99mTc-MDP bone SPECT scan with various background levels. Results Simulation results demonstrated that the overlapping projections from the 2nd MPHC pair generate increased image artifacts with increased degree of overlap and background activity level. The artifacts worsen with overlap of the projections of the high contrast lesions. However, the dual-step image reconstruction method using projections from both MPHC pairs provides artifact-free reconstructed images even at high degrees of overlap and background activity levels. Conclusions A dual-step MPH OS-EM image reconstruction method has been developed to provide artifact-free MPH SA SPECT images when apply to a mix of non-overlapping and overlapping projections obtained from a novel dual-pair MPHC set. Experimental studies are underway to confirm results of the simulation studies using several dual-pair MPHC sets. Research Support NIH R01 EB1558, research grant from Gamma Medic