MRI磁场对小动物PET空间分辨率影响的仿真研究  

Simulation study of the influence of MRI magnetic field on the PET spatial resolution of small animal

作　　者：徐桓[1,2] 胡红波 鲁家豪[2] 孟奥 赵庆军 XU Huan;HU Hong-bo;LU Jia-hao(Department of Radiation Instrument Examination,Institute for Inspection of Drug and Instrument,Sanitary Bureau of Logistics Support Department,Beijing 100071;Faculty of Biomedical Engineering,Engineering College,Peking Univeristy,Beijing 100071,Chin)

机构地区：[1]总后勤部卫生部药品仪器检验所放射室,北京100071 [2]北京大学工学院生物医学工程系,北京100871 [3]原广州军区联勤部药品仪器检验所,广东广州510000

出　　处：《中国医学装备》2018年第7期40-44,共5页China Medical Equipment

基　　金：国家重点研发计划(2016YFC0103400)"医学成像与放射治疗质量控制体模研发"

摘　　要：目的:研究不同强度的磁场对正电子自由程以及小动物正电子发射断层成像(PET)的空间分辨率的影响。方法:利用蒙特卡罗工具GATE软件建立磁兼容的小动物PET仿真模型,对放射性核素18F、11C、13N、15O及22Na在人体中水、肺、骨不同物质的正电子自由程进行仿真,并依据美国电气制造商协会(NEMA)NU4-2008标准要求对PET空间分辨率进行测量,分析磁场对自由程和空间分辨率的影响。结果:磁场对不同核素正电子自由程和空间分辨率的影响不同,对于18F和22Na等低能核素,9.4 T场强下自由程则分别减少24.5%和20.9%,但空间分辨率并无显著改变。对于15O和11C高能核素,自由程则分别减少61.5%和42.2%,空间分辨率也随着场强增加而提升,但在场强>7 T后基本趋于稳定。结论:小动物PET的空间分辨率在垂直磁场方向有一定提升,提升的幅度与正电子自由程和磁场强度相关。Objective： To research the effect of magnetic field of different intensity on the positron range and the spatial resolution of positron emission tomography（PET） of small animal. Methods： Monte Carlo tool（GATE software） was applied to establish simulation model of small animal PET which was compatible with magnetic field. And the positron ranges of various substance of radionuclide included ^18 F, ^11 C, ^13 N, ^15 O and ^22 Na in the water, lung and bone of human body were simulated. According to the requirement of NEMA NU4-2008 standard to measure spatial resolution of PET, and analyze the influence of magnetic field on the positron range and spatial resolution. Results： The influence of magnetic field for different positron range and spatial resolution was different. For nuclide with low power, such as ^18 F and ^22 Na, the positron range under 9.4 T field intensity were 24.5% and 20.9%, respectively, while the spatial resolution was no significantly changed. For nuclide with high power, such as ^15 O and ^11 C, the positron range were reduced 61.5% and 42.4%, respectively, and the spatial resolution also enhanced with the increasing of field intensity and it basically entered stability while field intensity was more than 7 T. Conclusion： The spatial resolution of small animal PET is promoted at the direction that was vertical to magnetic field, and the promoted range is relevant with positron range and magnetic field intensity.

关 键 词：正电子发射断层成像 硅基光电倍增管 GATE软件 仿真 空间分辨率 磁场强度 

分 类 号：R445.2[医药卫生—影像医学与核医学]