A GATE evaluation of the sources of error in quantitative 90Y PET
A GATE evaluation of the sources of error in quantitative 90Y PET
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DOI：
10.1118/1.4961747
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发表时间：
2016-10-01
期刊：
影响因子：
3.8
通讯作者：
Buvat, Irene
中科院分区：
文献类型：
--
作者：
Strydhorst, Jared;Carlier, Thomas;Buvat, Irene
目的：使用栓塞后PET扫描准确重建Y-90微球递送的剂量将允许建立更准确的Y-90治疗肝细胞癌的剂量-反应关系。然而，获得的PET数据的质量受到多种因素的影响，包括较差的计数统计数据和非常高的随机分数。这项工作使用Monte Carlo模拟来研究除了低计数统计之外的影响因素对Y-90 PET的量化有什么影响。方法：使用GATE模拟两个体模的PET采集-NEMA PET体模和NEMA IEC PET体模-包含Y-90或F-18。使用模拟数据的子集创建模拟投影，允许随机，散射，和LSO背景进行独立评估。模拟投影重建使用商业软件的模拟扫描仪，重建的定量准确性和对比度恢复重建images.Results：Y-90重建的定量准确性没有强烈的影响，由高随机分数存在于投影数据，和活性浓度恢复到5%以内的已知值。Y-90模拟数据的对比度恢复比F-18模拟数据稍差，具有相似的计数统计。然而，降解与任何特定因素没有密切联系。使用更有限的能量范围来减少投影中的随机分数没有显著效果。对Y-90 PET的模拟证实，用F-18所用的相同方法可以实现定量的Y-90，并且通过尝试模拟Y-90独特的方面可能没有什么改进余地，例如高得多的随机分数或在单个数据中存在韧致辐射。(C)2016年美国医学物理学家协会。
Purpose: Accurate reconstruction of the dose delivered by Y-90 microspheres using a postembolization PET scan would permit the establishment of more accurate dose-response relationships for treatment of hepatocellular carcinoma with Y-90. However, the quality of the PET data obtained is compromised by several factors, including poor count statistics and a very high random fraction. This work uses Monte Carlo simulations to investigate what impact factors other than low count statistics have on the quantification of Y-90 PET.Methods: PET acquisitions of two phantoms-a NEMA PET phantom and the NEMA IEC PET body phantom-containing either Y-90 or F-18 were simulated using GATE Simulated projections were created with subsets of the simulation data allowing the contributions of random, scatter, and LSO background to be independently evaluated. The simulated projections were reconstructed using the commercial software for the simulated scanner, and the quantitative accuracy of the reconstruction and the contrast recovery of the reconstructed images were evaluated.Results: The quantitative accuracy of the Y-90 reconstructions were not strongly influenced by the high random fraction present in the projection data, and the activity concentration was recovered to within 5% of the known value. The contrast recovery measured for simulated Y-90 data was slightly poorer than that for simulated F-18 data with similar count statistics. However, the degradation was not strongly linked to any particular factor. Using a more restricted energy range to reduce the random fraction in the projections had no significant effect.Conclusions: Simulations of Y-90 PET confirm that quantitative Y-90 is achievable with the same approach as that used for F-18, and that there is likely very little margin for improvement by attempting to model aspects unique to Y-90, such as the much higher random fraction or the presence of bremsstrahlung in the singles data. (C) 2016 American Association of Physicists in Medicine.