Springer International Publishing AG;Berlin/Heidelberg: Springer Berlin Heidelberg
摘要:
摘要： For high-spatial-resolution reconstructions in SPECT imaging, an accurate and fine system matrix ( H matrix) should be constructed. In this study, the modified Gaussian interpolation method (GIM) and the modified GIM combined with geometric parameter estimations (GIMGPE) are developed to rapidly construct the complete H matrices of circular-orbit 1-pinhole/4-pinhole SPECT systems. The multi-module multi-resolution (M 3 R) pinhole SPECT system (in the Center for Gamma-Ray Imaging, University of Arizona) is utilized to verify the usefulness of the proposed interpolation methods. The modified GIM and GIMGPE apply a geometric calibration, a rough grid-scan experiment, and point response parameterization based on Gaussian fitting to construct the full H matrices with a 0.5-mm voxel size and 60 projection angles. The geometric calibration uses a 3-point calibration phantom projected at 60 projection angles to construct the geometric projection model. In the rough grid-scan experiment, a point source is stepped on a regular grid pattern with a 1-mm grid spacing to measure the point response functions (PRFs) at the 0° projection angle. Sequentially, the measured PRFs are parameterized into two-dimensional Gaussians. The PRFs of full H matrices are interpolated by the relations between the Gaussian coefficients and the geometric parameters. The processing time of constructing the complete H matrices with the modified GIM and GIMGPE are respectively reduced by about 347× and 336×, compared to that of the full three-dimensional grid-scan experiment. According to the results of geometric calibration, the magnification of M 3 R with 1- and 4-pinhole patterns are 1.9× and 2.6×, respectively. The reconstructions of a hot-rod phantom show that the spatial resolutions of M 3 R with 1- and 4-pinhole patterns are 1.4 mm and 1.0 mm, respectively. 其他題名： J. Med. Biol. Eng 出版者： Berlin/Heidelberg: Springer Berlin Heidelberg 出版日期： 2016-08-01 出處： Journal of medical and biological engineering, 2016-08, Vol.36 (4), p.515-525 資源來源： ProQuest 版權： Taiwanese Society of Biomedical Engineering 2016 版權： Copyright Springer Science & Business Media 2016 版權： Taiwanese Society of Biomedical Engineering 2016. 識別號： ISSN: 1609-0985 識別號： EISSN: 2199-4757 識別號： DOI: 10.1007/s40846-016-0160-x
