EQPlanar: a maximum-likelihood method for accurate organ activity estimation from whole body planar projections.
EQPlanar: a maximum-likelihood method for accurate organ activity estimation from whole body planar projections.
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DOI：
10.1088/0031-9155/56/17/004
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发表时间：
2011-09-07
影响因子：
3.5
通讯作者：
Frey EC
中科院分区：
文献类型：
--
作者：
Song N;He B;Wahl RL;Frey EC
优化靶向放射性核素治疗(TRT)需要对患者特定的器官剂量进行估计。器官剂量是通过定量的核医学成像研究来估计的，其中许多研究涉及平面全身扫描。我们之前已经开发了定量平面(QPlanar)处理方法，并使用物理模型和模拟研究证明了其能够提供比传统的基于几何平均的平面(CPlanar)处理方法更准确的活动估计。QPlanar方法使用最大似然-期望最大化(ML-EM)算法、3D器官VOI和物理图像退化因素的严格模型来估计器官活动。然而，QPlanar方法要求3D器官VOI和2D平面投影之间的对准，并假设每个VOI中的活动分布均匀。这使得对患者的应用具有挑战性。因此，在本文中，我们提出了一种扩展的QPlanar(EQPlanar)方法，它提供独立器官刚性配准，并包括多个背景区域。我们已经使用蒙特卡罗模拟和患者数据验证了该方法。在仿真研究中，我们对该方法的精度和准确度进行了评估，并与原QPlanar方法进行了比较。在患者研究中，我们以注射后24小时的SPECT定量重建为金标准，将注射后24小时的器官活动估计与传统的基于几何平均的平面量化的估计进行了比较。我们还比较了在其他4个没有金标数据的时间点，由EQ Planar方法得到的测量和估计的投影与原始方法得到的预测的拟合优度。在模拟研究中，与QPlanar方法相比，EQPlanar方法为所有器官在所有时间点提供了更准确的活动估计。基于患者数据，我们得出结论，与以24小时SPECT为黄金标准的CPlanar方法相比，EQPlanar方法从24小时平面图像估计器官活动的准确性大幅提高。对于没有黄金标准的其他时间点，使用EQPlanar方法比使用QPlanar方法在估计和测量预测之间观察到更好的一致性。这一现象与在模拟数据和24小时患者数据中看到的拟合优度的改善是一致的。因此，这表明通过EQ Planar方法获得的器官活动估计的可靠性得到了提高。
Optimizing targeted radionuclide therapy (TRT) requires patient-specific estimation of organ doses. The organ doses are estimated from quantitative nuclear medicine imaging studies, many of which involve planar wholebody scans. We have previously developed the Quantitative Planar (QPlanar) processing method and demonstrated its ability to provide more accurate activity estimates than conventional geometric-mean based planar (CPlanar) processing methods using physical phantom and simulation studies. The QPlanar method uses the maximum likelihood-expectation maximization (ML-EM) algorithm, 3D organ VOIs, and rigorous models of physical image degrading factors to estimate organ activities. However, the QPlanar method requires alignment between the 3D organ VOIs and the 2D planar projections and assumes uniform activity distribution in each VOI. This makes application to patients challenging. As a result, in this paper we propose an extended QPlanar (EQPlanar) method that provides independent-organ rigid registration and includes multiple background regions. We have validated this method using both Monte Carlo simulation and patient data. In the simulation study, we evaluated the precision and accuracy of the method in comparison to the original QPlanar method. For the patient studies, we compared organ activity estimates at 24 hours after injection with those from conventional geometric mean based planar quantification using a 24 hour post-injection quantitative SPECT reconstruction as the gold standard. We also compared the goodness of fit of the measured and estimated projections obtained from EQPlanar method to those from the original method at 4 other time points where gold standard data was not available. In the simulation study, more accurate activity estimates were provided by the EQPlanar method for all the organs at all the time points compared with the QPlanar method. Based on the patient data, we concluded that the EQPlanar method provided a substantial increase in accuracy of organ activity estimates from 24 hr planar images compared to the CPlanar using 24 hr SPECT as the golden standard. For other time points, where no golden standard is available, better agreement between estimated and measured projections was observed by using EQPlanar method compared to the QPlanar method. This phenomenon is consistent with the improvement in goodness of fit seen in both simulation data and 24 hr patient data. Therefore, this indicates the improved reliability of organ activity estimates obtained though EQPlanar method.
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影响因子：
1.3
作者：
CARSON, RE
通讯作者：
CARSON, RE
影响因子：
3.5
作者：
He, B;Du, Y;Frey, EC
通讯作者：
Frey, EC
影响因子：
3.8
作者：
He, Bin;Wahl, Richard L.;Frey, Eric C.
通讯作者：
Frey, Eric C.
影响因子：
3.1
作者：
Eary, JF;Krohn, KA;Bernstein, ID
通讯作者：
Bernstein, ID
影响因子：
3.5
作者：
Song, N.;He, B.;Frey, E. C.
通讯作者：
Frey, E. C.