Choice of collimator for cardiac SPET when resolution compensation is included in iterative reconstruction
Choice of collimator for cardiac SPET when resolution compensation is included in iterative reconstruction
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DOI：
10.1007/s002590000387
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发表时间：
2001-01-01
期刊：
影响因子：
--
通讯作者：
Beekman, FJ
中科院分区：
文献类型：
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作者：
Lau, YH;Hutton, BF;Beekman, FJ
在临床心脏单光子发射断层扫描（SPET）研究中，不同空间分辨率和几何效率的准直器可用于成像。在为临床使用选择适当的准直器时，在可能限制重建图像的对比度的空间分辨率与确定图像中的噪声的检测效率之间存在折衷。我们的目标是评估在进行重建时（有和没有距离相关分辨率（CDR）补偿），哪种准直器最适合心脏SPET。动态MCAT胸部体模用于模拟180度锝-99m心脏数据，使用通用（GP）或高分辨率（HR）准直器采集。对于GP和HR，15 cm处的分辨率分别为11.5 mm和9.5 mm，相应的相对效率分别为1.0和0.52。投影数据中包括距离相关分辨率、衰减和噪声;不包括散射。在有和没有CDR的情况下进行有序子集期望最大化重建（子集大小4）。通过比较心肌恢复系数和心肌与心室之间相对于原始体模的对比度来评价结果，每个都针对对应于增加迭代次数的不同噪声水平绘制。研究表明，在没有CDR的情况下，HR给出了最佳结果。然而，对于任何给定的噪声水平与CDR，GP给出了优越的上级恢复和对比度。这些发现在物理体模研究中得到证实。结果表明，改善重建可以实现使用GP准直器与分辨率补偿相结合。
In clinical cardiac single-photon emission tomography (SPET) studies, collimators of different spatial resolution and geometric efficiency are available for imaging. In selecting the appropriate collimator for clinical use, there is a trade-off between spatial resolution, which can limit the contrast of the reconstructed image, and detection efficiency, which determines the noise in the image. Our objective was to assess which collimator is best suited for cardiac SPET when reconstruction is performed with and without compensation for distance-dependent resolution (CDR). The dynamic MCAT thorax phantom was used to simulate 180 degrees technetium-99m cardiac data, acquired using either a general-purpose (GP) or high-resolution (HR) collimator. For GP and HR, the resolution at 15 cm was 11.5 mm and 9.5 mm respectively, and the corresponding relative efficiency was 1.0 and 0.52 respectively. Distance-dependent resolution, attenuation and noise were included in the projection data; scatter was not included. Ordered subsets expectation maximisation reconstruction (subset size 4) was performed with and without CDR. Results were evaluated by comparing the myocardial recovery coefficient and contrast between myocardium and ventricle relative to the original phantom, each plotted for different noise levels corresponding to increasing iteration number. The study demonstrated that, without CDR, HR gave the best results. However, for any given noise level with CDR, GP gave superior recovery and contrast. These findings were confirmed in a physical phantom study. Results suggest that improved reconstruction can be achieved using a GP collimator in combination with resolution compensation.