Simulation study of spatial resolution and sensitivity for the tapered depth of interaction PET detectors for small animal imaging.
Simulation study of spatial resolution and sensitivity for the tapered depth of interaction PET detectors for small animal imaging.
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DOI：
10.1088/0031-9155/55/2/n04
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发表时间：
2010-01-21
影响因子：
3.5
通讯作者：
Cherry SR
中科院分区：
文献类型：
--
作者：
St James S;Yang Y;Bowen SL;Qi J;Cherry SR
可以通过提高扫描仪的灵敏度和空间分辨率来改进当前的小动物 PET 扫描仪。过去，人们努力最小化轴向和横轴方向的晶体尺寸以提高空间分辨率，并努力增加晶体长度以提高扫描仪的灵敏度。我们设计了锥形 PET 探测器，旨在减少探测器模块之间的间隙并优化下一代小动物 PET 扫描仪的灵敏度。在这项工作中，我们使用蒙特卡罗模拟研究基于锥形探测器元件的扫描仪的空间分辨率和灵敏度。对于锥形探测器元件，每个探测器使用更多的闪烁材料，从而导致扫描仪的灵敏度更高。然而，由于探测器元件的尺寸不均匀，空间分辨率也会下降。为了研究锥形 PET 探测器的特性，针对基于传统长方体探测器的系统和基于锥形探测器的扫描仪模拟了单环扫描仪的空间分辨率和灵敏度。此外，还评估了交互深度 (DOI) 分辨率对传统探测器和锥形探测器空间分辨率的影响。所有模拟均使用蒙特卡罗模拟包 GATE 进行。与相同环直径的传统探测器相比，使用锥形阵列可将整个视场的灵敏度提高 64%。研究发现 DOI 编码水平是决定径向空间分辨率的主导因素，而不是探测器形状。对于所有级别的 DOI 编码，在比较锥形和长方体探测器时，没有发现空间分辨率存在显着差异。采用锥形晶体设计以及出色的 DOI 分辨率的探测器将使 PET 扫描仪在整个视场内具有更高的灵敏度和均匀的空间分辨率。
Improvements to current small animal PET scanners can be made by improving the sensitivity and the spatial resolution of the scanner. In the past, efforts have been made to minimize the crystal dimensions in the axial and transaxial directions to improve the spatial resolution and to increase the crystal length to improve the sensitivity of the scanner. We have designed tapered PET detectors with the purpose of reducing the gaps between detector modules and optimizing the sensitivity of a future generation small animal PET scanner. In this work, we investigate spatial resolution and sensitivity of a scanner based on tapered detector elements using Monte Carlo simulations. For tapered detector elements more scintillation material is used per detector resulting in a higher sensitivity of the scanner. However, since the detector elements are not uniform in size, degradation in spatial resolution is also expected. To investigate characteristics of tapered PET detectors the spatial resolution and sensitivity of a one-ring scanner were simulated for a system based on traditional cuboid detectors and a scanner based on tapered detectors. Additionally, the effect of depth of interaction (DOI) resolution on the spatial resolution for the traditional and tapered detectors was evaluated. All simulations were performed using the Monte Carlo simulation package GATE. Using the tapered arrays a 64 % improvement in the sensitivity across the field of view was found compared with traditional detectors for the same ring diameter. The level of DOI encoding was found to be the dominating factor in determining the radial spatial resolution and not the detector shape. For all levels of DOI encoding, no significant difference was found for the spatial resolution when comparing the tapered and the cuboid detectors. Detectors employing the tapered crystal design along with excellent DOI resolution will lead to PET scanners with higher sensitivity and uniform spatial resolution across the field of view.