Performance comparison of finely pixelated LYSO- and GAGG-based Si-PM gamma cameras for high resolution SPECT
Performance comparison of finely pixelated LYSO- and GAGG-based Si-PM gamma cameras for high resolution SPECT
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DOI：
10.1016/j.nima.2017.08.013
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发表时间：
2017-11
影响因子：
1.4
通讯作者：
K. Nakanishi;S. Yamamoto;J. Kataoka
中科院分区：
文献类型：
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作者：
K. Nakanishi;S. Yamamoto;J. Kataoka
尽管Lu基闪烁体，包括掺杂Ce的Lu 1. 8 Y 0. 2 SiO 5 (LYSO)闪烁体，通常用于正电子发射断层扫描(PET)探测器，但它们并不常用于单光子发射计算机断层扫描(SPECT)的伽玛相机，因为会检测到由于Lu中天然放射性同位素污染而导致的背景计数。然而，一些研究报告称，由于天然放射性同位素背景计数导致的图像对比度恶化并不重要，因此 LYSO 有希望用于 SPECT 探测器。同时，一种新型闪烁体——Ce掺杂的Gd 3 Al 2 Ga 3 O 12 (GAGG)，具有高光产额且不含天然放射性同位素，已被开发出来，也被认为是一种有前途的闪烁体。因此，我们比较了 LYSO 和 GAGG 的性能，以确定哪一个更适合用于 SPECT 的基于硅光电倍增管 (Si-PM) 的高分辨率小视场 (FOV) 伽玛相机。我们使用精细像素化的 LYSO 和 GAGG 板，将其与 Si-PM 阵列光学耦合以形成伽马相机，并测量 122 keV 伽马光子的基本性能。基于 LYSO 和 GAGG 的 Si-PM 伽玛相机的能量分辨率分别为 30% 和 23% 半峰全宽 (FWHM)。基于 GAGG (∼ 0. 5 mm FWHM) 的伽马相机的固有空间分辨率优于 LYSO (∼ 0. 6 mm FWHM)。基于 LYSO 的伽玛相机的背景计数是 GAGG 的 28 倍。基于这些结果，我们得出结论，GAGG 比 LYSO 更适合开发用于高分辨率 SPECT 的基于 Si-PM 的伽马相机。
Although Lu-based scintillators, including Ce-doped Lu 1. 8 Y 0. 2 SiO 5 (LYSO) scintillators, are often used for positron emission tomography (PET) detectors, they are not commonly used in gamma cameras for single-photon emission computed tomography (SPECT) because background counts due to contamination of the natural radioisotope in Lu are detected. However, several studies report that deterioration in image contrast due to background counts of the natural radioisotope is not critical and thus LYSO is promising for use in SPECT detectors. Meanwhile, a new scintillator, the Ce-doped Gd 3 Al 2 Ga 3 O 12 (GAGG) with a high light yield and no natural radioisotope, has been developed and is also thought to be a promising scintillator. Thus, we compared the performance of LYSO with that of GAGG to determine which is more appropriate for a silicon photomultiplier (Si-PM)-based high-resolution small field-of-view (FOV) gamma camera for SPECT. We used finely pixelated LYSO and GAGG plates that were optically coupled to Si-PM arrays to form gamma cameras and measured the basic performance for 122-keV gamma photons. The energy resolutions of the LYSO-and GAGG-based Si-PM gamma cameras were 30% and 23% full width at half maximum (FWHM), respectively. The intrinsic spatial resolution of the GAGG (∼ 0. 5 mm FWHM) based gamma camera was better than that of the LYSO (∼ 0. 6 mm FWHM). The background counts of the LYSO-based gamma camera were 28 times larger than that of the GAGG. Based on these results, we conclude that GAGG is more appropriate than LYSO for the development of a Si-PM based gamma camera for high resolution SPECT.