%0 Journal Article
%T Region-Based Partial Volume Correction Techniques for PET Imaging: Sinogram Implementation and Robustness
%A Mike Sattarivand
%A Jennifer Armstrong
%A Gregory M. Szilagyi
%A Maggie Kusano
%A Ian Poon
%A Curtis Caldwell
%J International Journal of Molecular Imaging
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/435959
%X Background/Purpose. Limited spatial resolution of positron emission tomography (PET) requires partial volume correction (PVC). Region-based PVC methods are based on geometric transfer matrix implemented either in image-space (GTM) or sinogram-space (GTMo), both with similar performance. Although GTMo is slower, it more closely simulates the 3D PET image acquisition, accounts for local variations of point spread function, and can be implemented for iterative reconstructions. A recent image-based symmetric GTM (sGTM) has shown improvement in noise characteristics and robustness to misregistration over GTM. This study implements the sGTM method in sinogram space (sGTMo), validates it, and evaluates its performance. Methods. Two 3D sphere and brain digital phantoms and a physical sphere phantom were used. All four region-based PVC methods (GTM, GTMo, sGTM, and sGTMo) were implemented and their performance was evaluated. Results. All four PVC methods had similar accuracies. Both noise propagation and robustness of the sGTMo method were similar to those of sGTM method while they were better than those of GTMo method especially for smaller objects. Conclusion. The sGTMo was implemented and validated. The performance of the sGTMo in terms of noise characteristics and robustness to misregistration is similar to that of the sGTM method and improved compared to the GTMo method. 1. Introduction In spite of continuous improvement in the instrumentation of positron emission tomography (PET), its spatial resolution still remains relatively low compared to anatomical imaging modalities such as magnetic resonance (MR) or computed tomography (CT). Failure to implement a partial volume correction (PVC) in quantitative PET imaging may result in significant bias in the estimate of regional radioactivity uptake [1¨C3]. The limited spatial resolution of PET is due to several factors that influence the image formation processes, including positron range, noncollinearity, detector width, and reconstruction filtering [4]. Two distinct effects are usually associated with the partial volume effect [5]. The first is the point response effect, which causes spillover between different regions. This effect can be accounted for with a knowledge of the three-dimensional (3D) PET image formation processes or a measurement of the global PET point spread function (PSF). Usually, a fitted 3D Gaussian curve characterized by its full width half maximums (FWHMs) in the , , and directions is used to estimate the global PET PSF. The second effect is the tissue fraction effect due to the coarse
%U http://www.hindawi.com/journals/ijmi/2013/435959/