Park Sang-June, Leslie Rogers W, Huh Sam, Kagan Harris, Honscheid Klaus, Burdette Don, Chesi Enrico, Lacasta Carlos, Llosa Gabriela, Mikuz Marko, Studen Andrej, Weilhammer Peter, Clinthorne Neal H
Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, USA.
Nucl Instrum Methods Phys Res A. 2007 Jan 21;570(3):543-555. doi: 10.1016/j.nima.2006.10.277.
A very high resolution small animal positron emission tomograph (PET) which can achieve sub-millimeter spatial resolution is being developed using silicon pad detectors. The prototype PET for a single slice instrument consists of two 1 mm thick silicon pad detectors, each containing a 32 x 16 array of 1.4 mm x 1.4 mm pads read out with four VATAGP3 chips which have 128 channels low-noise self triggering ASIC in each chip, coincidence units, a source turntable and tungsten slice collimator. The silicon detectors were located edgewise on opposite sides of a 4 cm field-of-view to maximize efficiency. Energy resolution is dominated by electronic noise, which is 0.98% (1.38 keV) FWHM at 140.5 keV. Coincidence timing resolution is 82.1 ns FWHM and coincidence efficiency was measured to be 1.04 x 10(-3) % from two silicon detectors with annihilation photons of (18)F source Image data were acquired and reconstructed using conventional 2-D filtered-back projection (FBP) and a maximum likelihood expectation maximization (ML-EM) method. Image resolution of approximately 1.45 mm FWHM is obtained from 1-D profile of 1.1 mm diameter (18)F line source image. Even better resolution can be obtained with smaller detector element sizes. While many challenges remain in scaling up the instrument to useful efficiency including densely packed detectors and significantly improved timing resolution, performance of the test setup in terms of easily achieving submillimeter resolution is compelling.
一种使用硅垫探测器开发的超高分辨率小动物正电子发射断层扫描仪（PET），其空间分辨率可达亚毫米级。单切片仪器的PET原型由两个1毫米厚的硅垫探测器组成，每个探测器包含一个32×16的1.4毫米×1.4毫米垫子阵列，由四个VATAGP3芯片读出，每个芯片有128通道低噪声自触发ASIC、符合单元、源旋转台和钨切片准直器。硅探测器沿边缘放置在4厘米视野的相对两侧，以最大化效率。能量分辨率主要由电子噪声决定，在140.5 keV时，其半高宽为0.98%（1.38 keV）。符合定时分辨率为82.1 ns半高宽，使用（18）F源的湮灭光子，从两个硅探测器测得的符合效率为1.04×10（-3）%。使用传统的二维滤波反投影（FBP）和最大似然期望最大化（ML-EM）方法采集和重建图像数据。从直径1.1毫米的（18）F线源图像的一维剖面图中获得了约1.45毫米半高宽的图像分辨率。使用更小的探测器元件尺寸可以获得更好的分辨率。虽然在将仪器扩展到有用效率方面仍有许多挑战，包括密集排列的探测器和显著提高的定时分辨率，但测试装置在轻松实现亚毫米分辨率方面的性能令人信服。
