Scatter compensation methods in 3D iterative SPECT reconstruction: A simulation study
Scatter compensation methods in 3D iterative SPECT reconstruction: A simulation study
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DOI：
10.1088/0031-9155/42/8/011
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发表时间：
1997-08-01
影响因子：
3.5
通讯作者：
Frey, EC
中科院分区：
文献类型：
--
作者：
Beekman, FJ;Kamphuis, C;Frey, EC
不同的散射补偿方法纳入全三维迭代重建的效果进行了研究。这些方法是：（i）包括“理想散射估计”（伊势）;（ii）类似（i）但具有无噪声散射估计（ISE-NF）;（iii）在迭代重建期间将散射并入点扩散函数（“理想散射模型”，ISM）;（iv）无散射补偿（NSC）;（v）理想散射抑制（ISR），如可以通过使用具有完美能量分辨率的相机来近似。使用的迭代方法是有序子集期望最大化（OS-EM）算法。一个包含小冷球的圆柱体被用来计算对比度噪声曲线。对于大脑研究，计算了重建和“真实”分布之间的全局误差。结果表明，ISR方法优于其他方法，具有上级的优点。在所有考虑的情况下，ISM是上级伊势和执行大约一样好（脑研究）或优于（圆柱体数据）ISE-NF。与NSC相比，ISM和伊势都改善了对比度-噪声曲线并降低了全局误差。在伊势的情况下，用高斯核模糊散点估计会导致大脑研究中的误差略有减少，特别是在低计数水平下。最佳高斯核大小强烈依赖于噪声水平。
Effects of different scatter compensation methods incorporated in fully 3D iterative reconstruction are investigated. The methods are: (i) the inclusion of an 'ideal scatter estimate' (ISE); (ii) like (i) but with a noiseless scatter estimate (ISE-NF); (iii) incorporation of scatter in the point spread function during iterative reconstruction ('ideal scatter model', ISM); (iv) no scatter compensation (NSC); (v) ideal scatter rejection (ISR), as can be approximated by using a camera with a perfect energy resolution. The iterative method used was an ordered subset expectation maximization (OS-EM) algorithm. A cylinder containing small cold spheres was used to calculate contrast-to-noise curves. For a brain study, global errors between reconstruction and 'true' distributions were calculated. Results show that ISR is superior to all other methods. In all cases considered, ISM is superior to ISE and performs approximately as well as (brain study) or better than (cylinder data) ISE-NF. Both ISM and ISE improve contrast-to-noise curves and reduce global errors, compared with NSC. In the case of ISE, blurring of the scatter estimate with a Gaussian kernel results in slightly reduced errors in brain studies, especially at low count levels. The optimal Gaussian kernel size is strongly dependent on the noise level.