18 March 2008 Generic iterative reconstruction of multi-pinhole SPECT
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Single photon emission computerized tomographic (SPECT) images often suffer from low resolution and low count density. To improve spatial resolution of SPECT it is possible to use a pinhole collimator; however, this further reduces the system sensitivity. A potential solution to this problem is to use coded apertures, which offers increased sensitivity by using multiple pinholes, at the cost of increased image reconstruction time. A generic reconstruction algorithm has been developed which allows for arbitrary acquisition geometry via affine transforms (translation and rotation). The reconstruction process uses a (Siddon) ray projector, the expectation maximization (EM) algorithm and a 1 to n pinhole position matrix. Iteration times scale as a function of the number of pinholes in the collimator. Resolution recovery has also been incorporated into the reconstruction algorithm. The algorithm developed allows for the investigation of optimal imaging settings for small animal imaging. Simulated acquisitions of an ex-vivo rat heart with 1, 5 and 8 pinholes, over 360 degree acquisition, showing that multi-pinhole imaging can be successfully applied to rat cardiac imaging. Further refinement of the acquisition parameters, such as image overlap, collimator pinhole configuration and geometrical imaging configuration, will predict the theoretical settings for quantitative cardiac multi-pinhole SPECT imaging.
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William J. Ryder, William J. Ryder, Matthew P. Brennan, Matthew P. Brennan, Albert J. Sinusas, Albert J. Sinusas, Yi-Hwa Liu, Yi-Hwa Liu, } "Generic iterative reconstruction of multi-pinhole SPECT", Proc. SPIE 6913, Medical Imaging 2008: Physics of Medical Imaging, 69132M (18 March 2008); doi: 10.1117/12.769519; https://doi.org/10.1117/12.769519

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