Evaluation of quantitation accuracy for xSPECT
Evaluation of quantitation accuracy for xSPECT
复制标题
xSPECT 定量精度评估
DOI：
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
A. Vija
中科院分区：
文献类型：
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作者：
Jun Ma;A. Vija
西门子最近推出了xSPECT Quant（xQ）和xSPECT Bone（xB），这两款产品都可以实现99 mTc的定量SPECT。在这项工作中，我们评估的定量准确性xSPECT。我们在实验室中使用临床代表性Symbia Intevo测试系统获得了一个冷热球体模，并使用3% NIST可追溯57 Co源（校准灵敏度源（CSS））进行了校准。在步进和拍摄模式下采集投影，在360度范围内有120个视图，并且还被二次采样为60个视图（6度角步进）。我们使用了三种重建方法：xQ，xB和xEMAS（xE）在不同的更新。xE基于OSEM，但使用xSPECT中使用的投影运算符，目前尚未上市。测量背景和6个热球的平均放射性浓度（kBq/ml）。对于背景，选择大的均匀VOI。对于xQ和xE，我们选择了具有每个球体物理直径的80%的简化球体VOI，然而，我们使用内部球体体积作为xB的VOI，因为边界分层源于CT并用于重建。对于背景，所有方法都给出了与真实值相比误差在1%以内的估计。对于球体，xE和xQ具有几乎重叠的曲线。其准确度随球径的增大而逐渐提高，最大球径（16 ml）的准确度可达90%以上。即使对于最小的球体（0.5ml），xB也给出高得多的回收率（>60%），并且对于最大的球体（16 ml），xB上升到接近100%。这表明xB不仅导致相当高的分辨率，而且还可以产生更准确的定量估计。我们没有发现3度和6度抽样之间的定量差异显着。
Siemens recently introduced xSPECT Quant (xQ) and xSPECT Bone (xB), both enabling quantitative SPECT for 99mTc. In this work, we evaluate the quantitative accuracy of xSPECT. We acquired a Hot-Cold sphere phantom with a clinical representative Symbia Intevo test system in our lab and calibrated using a 3% NIST traceable 57Co source (Calibrated Sensitivity Source (CSS)). Projections are acquired in step-and-shoot mode with 120 views over 360 degrees, and are also subsampled to 60 views (6-degree angular step). We used three reconstruction methods: xQ, xB and xEMAS (xE) at varying updates. xE is based upon OSEM but uses the projection operator employed in xSPECT, and is currently not commercially available. Mean activity concentration (in kBq/ml) is measured for the background and the 6 hot spheres. For the background, a large uniform VOI is chosen. We chose a reduced sphere VOI with 80% of the physical diameter of each sphere for xQ and xE, however we use the interior sphere volume as VOI for xB, as the boundary delinaeation stems from CT and is used in the reconstruction. For the background, all methods give estimations within 1% of error margin compared to truth. For spheres, xE and xQ have almost overlapping curves. Their accuracy gradually improves with the increasing size of spheres, and reaches over 90% accuracy for the largest sphere (16ml). xB gives much higher recovery (>60%) even for the smallest sphere (0.5ml), and rises close to 100% for the largest sphere (16ml). This suggests that xB not only results in considerably higher resolution, but can also yield more accurate quantitation estimation. We did not find significant difference on quantitation between 3-degree and 6-degree sampling.
影响因子：
4.9
作者：
Cherry SR
通讯作者：
Cherry SR