该文提出一种马赛克式正电子发射断层成像(PET)探测器设计方案, 通过改变晶体的排布方式, 并基于GATE (Geant4 Application for Emission Tomography)软件模拟, 对3种马赛克PET的设计方案和传统的PET设计方案进行了多方面的对比, 对比的内容包括: 轴向探测效率、体源探测效率以及空间分辨率。并且进一步考虑能量下阈的影响, 比较能量下阈为0 keV、 250 keV和350 keV时各个方案测得的结果的变化。结果表明: 马赛克PET方案在不考虑能量下域时, 轴向探测效率提高24%~50%, 而体源探测效率更是可以提高47%~62%。当能量下阈为 250 keV 时, 方案4的轴向探测效率和体源探测效率可分别提升12%和8%, 于此同时其重建图像空间分辨率较传统方案相比接近。
There positron emission tomography (PET) mosaic designs were developed from a traditional PET design based on GATE (Geant4 Application for Emission Tomography) simulations using axial sensitivity, volume sensitivity and spatial resolutions with various energy thresholds of 0 keV, 250 keV and 350 keV. The results indicate that without the effect of the energy threshold, the axial sensitivity of the mosaic designs is increased 24%-50%, while the volume sensitivity is increased 47%-62%. With an appropriate energy threshold (250 keV), the axial sensitivity is increased by 12% while the volume sensitivity is increased by 8% to give similar image quality as the traditional design.
[1] MacDonald L R, Harrison R L, Alessio A M, et al. Effective count rates for PET scanners with reduced and extended axial field of view [J]. Physics in Medicine and Biology, 2011, 56(12): 3629-3643.
[2] Poon J K, MacDonald L R, Cherry S R, et al. A simulation study of a long axial field of view whole-body PET scanner using cylindrical and anthropomorphic phantoms [C]// Nuclear Science Symposium Conference Record. Dresden, Germany: IEEE, 2008: 4999-5006.
[3] Poon J K, Dahlbom M L, Moses W W, et al. Corrigendum: Optimal whole-body PET scanner configurations for different volumes of LSO scintillator: A simulation study [J]. Physics in Medicine and Biology, 2012, 57(23): 4077-4094.
[4] Surti S, Lee E, Werner M, et al. Imaging study of a clinical PET scanner design using an optimal crystal thickness and scanner axial FOV [C]// Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC). Valencia, Spain: IEEE, 2011: 3390-3394.
[5] Surti S, Werner M E, Karp J S. Study of PET scanner designs using clinical metrics to optimize the scanner axial FOV and crystal thickness [J]. Physics in Medicine and Biology, 2013, 58(12): 3995-4012.
[6] Yamaya T, Inaniwa T, Minohara S, et al. A proposal of an open PET geometry [J]. Physics in Medicine and Biology, 2008, 53(3): 757-773.
[7] Yamaya T, Yoshida E, Inaniwa T, et al. Development of a small prototype for a proof-of-concept of OpenPET imaging [J]. Physics in Medicine and Biology, 2011, 56(4): 1123-1137.
[8] Tashima H, Yamaya T, Yoshida E, et al. A single-ring OpenPET enabling PET imaging during radiotherapy [J]. Physics in Medicine and Biology, 2012, 57, 4705-4718.
[9] Yoshida E, Kinouchi S, Tashima H, et al. Developmentand performance evaluation of a single-ring OpenPET prototype [C]// Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC). Anaheim, USA: IEEE, 2012: 3125-3127.
[10] Jan S, Santin G, Strul D, et al. GATE: A simulation toolkit for PET and SPECT [J]. Physics in Medicine and Biology, 2004, 49(19): 4543-4561.
[11] Daubewitherspoon M E, Muehllehner G. Treatment of axial data in 3-dimensional PET [J]. Journal of Nuclear Medicine, 1987, 28(11): 1717-1724
[12] Defrise M, Kinahan P E, Townsend D W, et al. Exact and approximate rebinning algorithm for 3-D PET data [J]. IEEE Transaction on Medical Imaging, 1997, 16(2): 145-158.
