POSITION-SENSITIVE APD DETECTORS FOR SMALL ANIMAL PET

小动物PET扫描仪还没有达到可以达到的最高灵敏度和空间分辨率， 这在很大程度上是由于在大多数探测器设计中空间分辨率和效率之间的不利权衡。 该方案的目标是开发用于In的高分辨率、高灵敏度的深度编码探测器 基于位置敏感雪崩光电二极管(PSAPD)技术的PET活体分子成像 并研制了一种高空间分辨率和高分辨率的小动物扫描仪样机 基于PSAPD/LSO探测器模块的成像。PSAPD提供了几个有吸引力的功能，包括Low 密度读出(仅在四个信号输出中对事件位置进行编码)、薄横截面(支持双 结束闪烁体阵列的读出以提供相互作用信息的深度)和高量子效率。 初步数据已经清楚地表明，这些设备能够分辨1x1 mm交叉阵列 LSO晶体截面，并通过20 mm厚的探测器提供3-4 mm深度的相互作用分辨率。这个 这项建议中的研究旨在开发和优化适合于并入到 高分辨率、高灵敏度小动物PET扫描仪。具体地说，实验将解决 最小可分辨LSO晶体尺寸作为PSAPD表面积和温度的函数， 不同的PSAPD读出方案，交互作用的深度分辨率作为晶体长度、尺寸和 PSAPD的稳定性随时间、偏置电压和温度的变化而变化。一个 PSAPD/LSO PET探测器的完整评估将包括洪水直方图、个体 晶体能谱、相互作用深度分辨率、时间分辨率和固有空间分辨率。 将与基于位置灵敏光电倍增管的LSO探测器进行定量比较。 (目前在大多数小动物PET系统中使用的技术)。最后是一个简单的单探测器环 小动物PET扫描仪将使用优化的PSAPD/LSO探测器作为证明 概念。将为PET开发电子学、数据采集和图像重建算法 具有深度交互能力的系统。基于这些结果，性能(在空间方面) 分辨率和灵敏度)，由这些探测器模块建立的多环小动物PET系统 预测并与现有的商用小动物PET扫描仪进行比较。

Small-animal PET scanners have not reached the highest sensitivity and spatial resolution that is achievable, largely due to an unfavorable trade-off between spatial resolution and efficiency in most detector designs. The objective of this proposal is to develop high resolution, high sensitivity depth-encoding detectors for in vivo molecular imaging with PET based on position-sensitive avalanche photodiode (PSAPD) technology and develop a high spatial resolution and high resolution uniformity prototype scanner for small-animal imaging based on PSAPD/LSO detector modules. PSAPDs offer several attractive features including low density readout (event location is encoded in just four signal outputs), thin cross-section (enabling dual- ended read out of scintillator arrays to provide depth of interaction information) and high quantum efficiency. Preliminary data has clearly demonstrated the ability of these devices to resolve arrays of 1x1 mm cross- section LSO crystals and to provide a 3-4 mm depth of interaction resolution with 20 mm thick detectors. The research in this proposal seeks to develop and optimize PSAPD detectors suitable for incorporation into a high resolution, high sensitivity small-animal PET scanner. Specifically, experiments will address the minimum resolvable LSO crystal size as a function of PSAPD surface area and temperature, the effect of different PSAPD read out schemes, depth of interaction resolution as a function of crystal length, size, and surface treatment, and the stability of PSAPD as a function of time, bias voltage and temperature. A complete evaluation of PSAPD/LSO PET detectors will include measurements of flood histograms, individual crystal energy spectra, depth of interaction resolution, timing resolution and intrinsic spatial resolution. Quantitative comparison will be made to LSO detectors based on position sensitive photomultiplier tubes . (the technology currently used in most small-animal PET systems). Finally a simple single detector ring small-animal PET scanner will be developed using the optimized PSAPD/LSO detectors as a proof of concept. Electronics, data acquisition and image reconstruction algorithms will be developed for the PET system with depth of interaction capability. Based on these results, the performance (in terms of spatial resolution and sensitivity) of a multi-ring small-animal PET system built from these detector modules will be predicted and compared with available commercial small-animal PET scanners.