Intrinsic spatial resolution evaluation of the X’tal cube PET detector based on a 3D crystal block segmented by laser processing
Intrinsic spatial resolution evaluation of the X’tal cube PET detector based on a 3D crystal block segmented by laser processing
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基于激光加工分割的 3D 晶体块的 Xtal 立方体 PET 探测器的固有空间分辨率评估
DOI：
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发表时间：
2012
影响因子：
1.6
通讯作者：
T. Yamaya
中科院分区：
文献类型：
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作者：
E. Yoshida;H. Tashima;N. Inadama;F. Nishikido;T. Moriya;T. Omura;Mitsuo Watanabe;H. Murayama;T. Yamaya
X’tal 立方体是一种交互深度 (DOI)-PET 探测器，旨在通过有效读取晶体块六个面的闪烁光子来获得各向同性分辨率。 X'tal立方体由具有各向同性分辨率的3D晶体块和多像素光子计数器（MPPC）阵列组成。在这项研究中，为了高效、精确地制造 3D 晶体块，我们将次表面激光雕刻 (SSLE) 技术应用于单片晶体块，而不是粘合分段的小晶体。 SSLE 技术提供了微裂纹壁，可在整体闪烁体块中刻出凹槽。使用制造的 X’tal 立方体，我们评估了其固有的空间分辨率，以证明各向同性分辨率的概念。通过 SSLE 技术将 2 mm 间距的 3D 网格制作成 18 × 18 × 18 mm3 单片原硅酸镥钇 (LYSO) 晶体。 4 × 4 MPPC 光学耦合到晶体块的每个表面。 X’tal立方体受到22Na伽马射线均匀照射，3D位置直方图上的所有3D网格通过96通道MPPC信号的Anger型计算清晰分离。 X'tal 立方体的响应函数通过使用 22Na 点源扫描来测量。通过将 X'tal 立方体定位在垂直和 45° 入射角，以 0.25 mm 的步长扫描具有 1.0 mm 狭缝的伽马射线束。两个入射角的平均 FWHM 分辨率均为 2.1 毫米。因此，我们证实了X'tal立方体的各向同性空间分辨率性能。
The X’tal cube is a depth-of-interaction (DOI)-PET detector which is aimed at obtaining isotropic resolution by effective readout of scintillation photons from the six sides of a crystal block. The X’tal cube is composed of the 3D crystal block with isotropic resolution and arrays of multi-pixel photon counters (MPPCs). In this study, to fabricate the 3D crystal block efficiently and precisely, we applied a sub-surface laser engraving (SSLE) technique to a monolithic crystal block instead of gluing segmented small crystals. The SSLE technique provided micro-crack walls which carve a groove into a monolithic scintillator block. Using the fabricated X’tal cube, we evaluated its intrinsic spatial resolution to show a proof of concept of isotropic resolution. The 3D grids of 2 mm pitch were fabricated into an 18 × 18 × 18 mm3 monolithic lutetium yttrium orthosilicate (LYSO) crystal by the SSLE technique. 4 × 4 MPPCs were optically coupled to each surface of the crystal block. The X’tal cube was uniformly irradiated by 22Na gamma rays, and all of the 3D grids on the 3D position histogram were separated clearly by an Anger-type calculation from the 96-channel MPPC signals. Response functions of the X’tal cube were measured by scanning with a 22Na point source. The gamma-ray beam with a 1.0 mm slit was scanned in 0.25 mm steps by positioning of the X’tal cube at vertical and 45° incident angles. The average FWHM resolution at both incident angles was 2.1 mm. Therefore, we confirmed the isotropic spatial resolution performance of the X’tal cube.