Optimization and comparison of simultaneous and separate acquisition protocols for dual isotope myocardial perfusion SPECT.
Optimization and comparison of simultaneous and separate acquisition protocols for dual isotope myocardial perfusion SPECT.
复制标题
双同位素心肌灌注 SPECT 同时和单独采集方案的优化和比较。
DOI：
10.1088/0031-9155/60/13/5083
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发表时间：
2015
影响因子：
3.5
通讯作者：
Frey,EricC
中科院分区：
文献类型：
--
作者：
Ghaly,Michael;Links,JonathanM;Frey,EricC
与单独采集相比，双同位素同时采集 (DISA) 静息应激心肌灌注 SPECT (MPS) 协议具有许多优势。然而，由于患者体内的散射和准直器中的相互作用而导致的串扰污染会降低图像质量。补偿可以减少串扰的影响，但并不能完全消除图像质量下降。优化采集参数可以进一步减少串扰的影响。在本文中，我们使用理想观察者（IO）、真实的数字体模群体和蒙特卡罗（MC）模拟Tc-99m和Tl-201投影来研究剩余Tl-201能量窗口宽度和相对注入活动的优化，作为提高图像质量的手段。我们比较了 Tl-201 采集能量窗口宽度从 4 到 40 keV 变化（以 72 keV 为中心）的灌注缺陷检测任务的性能，相机的能量分辨率为 9%。我们还研究了 7 种不同的相对注射活性，定义为 Tc-99m 和 Tl-201 活性的比率，同时保持总有效剂量恒定在 13.5 mSv。对于每个能量窗口和相对注入活动，我们使用马尔可夫链蒙特卡罗 (MCMC) 方法计算 IO 测试统计数据，对 1,620 个固定和可逆的存在缺陷和无缺陷噪声图像的三元组进行建模，模拟真实的背景变化。估计 3 级接收器工作特性 (ROC) 表面 (VUS) 下的体积并作为品质因数。对于同步采集，IO 建议 2.6-5 的相对 Tc-to-Tl 注入活性比和 16-22% 的采集能量窗口宽度是最佳的。对于单独采集，我们观察到最佳相对注入活动范围从 2.6 到 12.1，采集能量窗口宽度为 16-22%。在这些范围内观察到Tl-201注射活性与Tl-201能量窗宽度之间呈负相关。结果还表明，DISA 方法可能提供与使用单独采集协议获得的图像质量一样好的图像质量。我们使用单独采集比较了优化方案和当前临床方案的观察者性能。目前的临床方案提供了更好的性能，但代价是向患者注射大约两倍的 Tc-99m 和 Tl-201，导致辐射剂量大幅增加。
Dual-isotope simultaneous-acquisition (DISA) rest-stress myocardial perfusion SPECT (MPS) protocols offer a number of advantages over separate acquisition. However, crosstalk contamination due to scatter in the patient and interactions in the collimator degrade image quality. Compensation can reduce the effects of crosstalk, but does not entirely eliminate image degradations. Optimizing acquisition parameters could further reduce the impact of crosstalk. In this paper we investigate the optimization of the rest Tl-201 energy window width and relative injected activities using the ideal observer (IO), a realistic digital phantom population and Monte Carlo (MC) simulated Tc-99m and Tl-201 projections as a means to improve image quality. We compared performance on a perfusion defect detection task for Tl-201 acquisition energy window widths varying from 4 to 40 keV centered at 72 keV for a camera with a 9% energy resolution. We also investigated 7 different relative injected activities, defined as the ratio of Tc-99m and Tl-201 activities, while keeping the total effective dose constant at 13.5 mSv. For each energy window and relative injected activity, we computed the IO test statistics using a Markov chain Monte Carlo (MCMC) method for an ensemble of 1,620 triplets of fixed and reversible defect-present, and defect-absent noisy images modeling realistic background variations. The volume under the 3-class receiver operating characteristic (ROC) surface (VUS) was estimated and served as the figure of merit. For simultaneous acquisition, the IO suggested that relative Tc-to-Tl injected activity ratios of 2.6–5 and acquisition energy window widths of 16–22% were optimal. For separate acquisition, we observed a broad range of optimal relative injected activities from 2.6 to 12.1 and acquisition energy window of widths 16–22%. A negative correlation between Tl-201 injected activity and the width of the Tl-201 energy window was observed in these ranges. The results also suggested that DISA methods could potentially provide image quality as good as that obtained with separate acquisition protocols. We compared observer performance for the optimized protocols and the current clinical protocol using separate acquisition. The current clinical protocols provided better performance at a cost of injecting the patient with approximately double the injected activity of Tc-99m and Tl-201, resulting in substantially increased radiation dose.