具有稀疏探测器环或棋盘配置的自适应轴向 FOV PET 扫描仪的物理性能。

Physical performance of adaptive axial FOV PET scanners with a sparse detector block rings or a checkerboard configuration.

机构信息

Department of Radiology, Weill Cornell Medical College, Cornell University, New York, NY, United States of America.

Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, United States of America.

出版信息

Phys Med Biol. 2022 May 12;67(10). doi: 10.1088/1361-6560/ac6aa1.

DOI:10.1088/1361-6560/ac6aa1

PMID:35472757

Abstract

Using Monte-Carlo simulations, we evaluated the physical performance of a hypothetical state-of-the-art clinical PET scanner with adaptive axial field-of-view (AFOV) based on the validated GATE model of the Siemens Biograph VisionPET/CT scanner.Vision consists of 16 compact PET rings, each consisting of 152 mini-blocks of 5 × 5 Lutetium Oxyorthosilicate crystals (3.2 × 3.2 × 20 mm). The Vision 25.6 cm AFOV was extended by adopting (i) a sparse mini-block ring (SBR) configuration of 49.6 cm AFOV, with all mini-block rings interleaved with 16 mm axial gaps, or (ii) a sparse mini-block checkerboard (SCB) configuration of 51.2 cm AFOV, with all mini-blocks interleaved with gaps of 16 mm (transaxial) × 16 mm (axial) width in checkerboard pattern. For sparse configurations, a 'limited' continuous bed motion (limited-CBM) acquisition was employed to extend AFOVs by 2.9 cm. Spatial resolution, sensitivity, image quality (IQ), NECR and scatter fraction were assessed per NEMA NU2-2012.All IQ phantom spheres were distinguishable with all configurations. SBR and SCB percent contrast recovery (% CR) and background variability (% BV) were similar (-value > 0.05). Compared to Vision, SBR and SCB %CRs were similar (-values > 0.05). However, SBR and SCB %BVs were deteriorated by 30% and 26% respectively (-values < 0.05). SBR, SCB and Vision exhibited system sensitivities of 16.6, 16.8, and 15.8 kcps MBq, NECRs of 311 kcps @35 kBq cc, 266 kcps @25.8 kBq cc, and 260 kcps @27.8 kBq cc, and scatter fractions of 31.2%, 32.4%, and 32.6%, respectively. SBR and SCB exhibited a smoother sensitivity reduction and noise enhancement rate from AFOV center to its edges. SBR and SCB attained comparable spatial resolution in all directions (-value > 0.05), yet, up to 1.5 mm worse than Vision (-values < 0.05).The proposed sparse configurations may offer a clinically adoptable solution for cost-effective adaptive AFOV PET with either highly-sensitive or long-AFOV acquisitions.

摘要

使用蒙特卡罗模拟，我们基于西门子 Biograph VisionPET/CT 扫描仪的经过验证的 GATE 模型，评估了具有自适应轴向视野（AFOV）的假设最先进临床 PET 扫描仪的物理性能。Vision 由 16 个紧凑的 PET 环组成，每个环由 152 个 5×5 硅酸镥（LSO）晶体的微型块组成（3.2×3.2×20 毫米）。通过采用（i）具有 49.6 cm AFOV 的稀疏微型块环（SBR）配置，或者（ii）具有 51.2 cm AFOV 的稀疏微型块棋盘（SCB）配置，将 Vision 的 25.6 cm AFOV 扩展，其中所有微型块环均采用 16 毫米轴向间隙交错排列，或者所有微型块以棋盘模式交错排列，具有 16 毫米（横向）×16 毫米（轴向）宽度的间隙。对于稀疏配置，采用“有限”连续床运动（有限-CBM）采集将 AFOV 扩展 2.9 cm。根据 NEMA NU2-2012 评估了空间分辨率、灵敏度、图像质量（IQ）、NECR 和散射分数。所有配置都可以分辨出所有 IQ 幻影球。SBR 和 SCB 的对比度恢复百分比（% CR）和背景变化率（% BV）相似（>0.05）。与 Vision 相比，SBR 和 SCB 的 % CR 相似（>0.05）。然而，SBR 和 SCB 的 % BV 分别恶化了 30%和 26%（<0.05）。SBR、SCB 和 Vision 的系统灵敏度分别为 16.6、16.8 和 15.8 kcps MBq，NECR 分别为 311 kcps@35 kBq cc、266 kcps@25.8 kBq cc 和 260 kcps@27.8 kBq cc，散射分数分别为 31.2%、32.4%和 32.6%。SBR 和 SCB 表现出从 AFOV 中心到边缘的灵敏度降低和噪声增强率更平滑。SBR 和 SCB 在所有方向上都具有可比的空间分辨率（>0.05），但比 Vision 差 1.5 毫米（<0.05）。所提出的稀疏配置可能为具有高灵敏度或长 AFOV 采集的经济高效的自适应 AFOV PET 提供一种临床可采用的解决方案。