Correction of nonuniform attenuation in cardiac SPECT imaging.
Correction of nonuniform attenuation in cardiac SPECT imaging.
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发表时间：
1989-04
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通讯作者：
Benjamin M. W. Tsui;G. T. Gullberg;E. Edgerton;J. Ballard;J. Perry;W. H. McCartney;J. Berg
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作者：
Benjamin M. W. Tsui;G. T. Gullberg;E. Edgerton;J. Ballard;J. Perry;W. H. McCartney;J. Berg
采用迭代期望最大化（EM）算法和迭代Chang算法测量衰减分布，对心脏SPECT成像中的光子衰减进行校正，并与传统的滤波反投影和无衰减校正的迭代EM算法进行比较。从透射计算机断层扫描研究中确定衰减分布，该研究是使用外部准直片源获得的。发射光子的衰减在EM算法中通过衰减投影仪-反投影仪建模，该衰减投影仪-反投影仪使用估计的衰减分布来计算沿着每个投影和反投影射线的每个像素的衰减因子。心肺体模研究和201 Tl患者研究的结果表明，衰减校正的迭代EM算法在减少条纹伪影和噪声方面提供了改善的图像质量，在存在均匀性的情况下，在改善放射性分布均匀性方面提供了更准确的定量信息，并提供了更好的解剖对象定义。
Correction for photon attenuation in cardiac SPECT imaging using a measured attenuation distribution with an iterative expectation maximization (EM) algorithm and an iterative Chang algorithm were compared with the conventional filtered backprojection and an iterative EM algorithm without attenuation correction. The attenuation distribution was determined from a transmission computed tomography study that was obtained using an external collimated sheet source. The attenuation of the emitting photons was modeled in the EM algorithm by an attenuated projector-backprojector that used the estimated attenuation distribution to calculate attenuation factors for each pixel along each projection and backprojection ray. Results from a heart-lung phantom study and a 201Tl patient study demonstrated that the iterative EM algorithm with attenuation correction provided improved image quality in terms of reduced streak artifacts and noise, and more accurate quantitative information in terms of improved radioactivity distribution uniformity where uniformity existed, and better anatomic object definition.