PET imaging with yttrium-86:: comparison of phantom measurements acquired with different PET scanners before and after applying background subtraction
PET imaging with yttrium-86:: comparison of phantom measurements acquired with different PET scanners before and after applying background subtraction
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DOI：
10.1007/s00259-002-1112-y
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发表时间：
2003-05-01
影响因子：
9.1
通讯作者：
Bartenstein, P
中科院分区：
文献类型：
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作者：
Buchholz, HG;Herzog, H;Bartenstein, P
使用正电子发射器 Y-86 进行定量成像是确定 Y-90 标记放射性药物的摄取和剂量测定的首选方法。为了检查 Y-86 正电子发射断层扫描结果的定量准确性，在带有聚四氟乙烯、水和空气棒的圆柱形模型中对这种非纯正电子发射器进行了评估，并使用三种不同的扫描仪进行了测量：ECAT EXACT (2D/3D)、ECAT HR+ (2D/3D) 和 PC4096+ (2D)。标准重建后，从第一次采集到最后一次采集（八个半衰期后），使用 ECAT EXACT 测量的 86Y 放射性以及与真实放射性的相关性在 2D 中变化在 0.84 到 0.99 之间，在 3D 中变化在 0.93 到 1.20 之间。与模型的实际 86Y 放射性相比，水和聚四氟乙烯棒表现出相当大量的重建放射性 - 水在 2D 中为 21%，在 3D 中为 67%，在聚四氟乙烯中分别为 65% 和 147%。对于 ECAT HR+，在 3D 中获得了类似的结果，但在 2D 中存在更大的高估。使用 PC4096+ 进行的测量显示出相当小的误差，水的误差为 10%，特氟龙的误差为 20%。为了校正伽马重合的背景，对正弦图进行了分析，并从正弦图中减去了背景的实验百分比。为了最大限度地减少重建放射性的误差，各个扫描仪和模式的减法值必须不同。我们的结果表明，如果基于 Y-90/Y-86 的骨骼和红骨髓剂量测定源自骨骼上的感兴趣区域，则必须谨慎对待，其密度与聚四氟乙烯的密度相似。为了获得更可靠的估计，必须根据扫描仪和采集模式应用和单独定制适当的背景校正。
Quantitative imaging with the positron emitter Y-86 is the method of choice to determine the uptake and dosimetry of Y-90-labelled radiopharmaceuticals. To examine the quantitative accuracy of positron emission tomography findings with Y-86, this non-pure positron emitter was evaluated in a cylindrical phantom with rods of Teflon, water and air and measured with three different scanners: ECAT EXACT (2D/3D), ECAT HR+ (2D/3D) and PC4096+ (2D). After standard reconstruction, 86Y radioactivity measured with the ECAT EXACT and related to the true radioactivity varied between 0.84 and 0.99 in 2D and between 0.93 and 1.20 in 3D from the first to the last acquisition (eight half-life times later). The water and Teflon rods exhibited considerable amounts of reconstructed radioactivity - 21% in 2D and 67% in 3D for water and 65% and 147%, respectively, for Teflon - compared with the actual 86Y radioactivity of the phantom. For the ECAT HR+ similar results were obtained in 3D, but there were even greater overestimations in 2D. Measurements with the PC4096+ showed rather small errors, with 10% for water and 20% for Teflon. To correct for the background of gamma-coincidences, sinograms were analysed and an experimental percentage of the background was subtracted from the sinograms. In order to minimise the errors in reconstructed radioactivity, the subtraction value had to be different for the individual scanners and modes. Our results demonstrate that Y-90/Y-86-based dosimetry for bone and red marrow must be regarded with caution if it is derived from regions of interest over the bone, the density of which is similar to that of Teflon. To obtain more reliable estimates, an appropriate background correction must be applied and tailored individually with respect to the scanner and acquisition mode.