Lazaro D, Buvat I, Loudos G, Strul D, Santin G, Giokaris N, Donnarieix D, Maigne L, Spanoudaki V, Styliaris S, Staelens S, Breton V
Laboratoire de Physique Corpusculaire, CNRS/IN2P3, Université de Clermont-Ferrand, 24 avenue des Landais, 63177 Aubière, France.
Phys Med Biol. 2004 Jan 21;49(2):271-85. doi: 10.1088/0031-9155/49/2/007.
Monte Carlo simulations are increasingly used in scintigraphic imaging to model imaging systems and to develop and assess tomographic reconstruction algorithms and correction methods for improved image quantitation. GATE (GEANT4 application for tomographic emission) is a new Monte Carlo simulation platform based on GEANT4 dedicated to nuclear imaging applications. This paper describes the GATE simulation of a prototype of scintillation camera dedicated to small-animal imaging and consisting of a CsI(Tl) crystal array coupled to a position-sensitive photomultiplier tube. The relevance of GATE to model the camera prototype was assessed by comparing simulated 99mTc point spread functions, energy spectra, sensitivities, scatter fractions and image of a capillary phantom with the corresponding experimental measurements. Results showed an excellent agreement between simulated and experimental data: experimental spatial resolutions were predicted with an error less than 100 microns. The difference between experimental and simulated system sensitivities for different source-to-collimator distances was within 2%. Simulated and experimental scatter fractions in a [98-182 keV] energy window differed by less than 2% for sources located in water. Simulated and experimental energy spectra agreed very well between 40 and 180 keV. These results demonstrate the ability and flexibility of GATE for simulating original detector designs. The main weakness of GATE concerns the long computation time it requires: this issue is currently under investigation by the GEANT4 and the GATE collaborations.
蒙特卡罗模拟在闪烁成像中越来越多地被用于对成像系统进行建模，以及开发和评估断层重建算法和校正方法，以改善图像定量分析。GATE（用于断层发射的GEANT4应用程序）是一个基于GEANT4的全新蒙特卡罗模拟平台，专门用于核成像应用。本文描述了对一款用于小动物成像的闪烁相机原型的GATE模拟，该相机由耦合到位置灵敏光电倍增管的CsI(Tl)晶体阵列组成。通过将模拟的99mTc点扩散函数、能谱、灵敏度、散射分数以及毛细管模型的图像与相应的实验测量结果进行比较，评估了GATE对相机原型建模的相关性。结果表明模拟数据与实验数据之间具有极好的一致性：预测的实验空间分辨率误差小于100微米。不同源到准直器距离下实验和模拟系统灵敏度之间的差异在2%以内。对于位于水中的源，在[98 - 182 keV]能量窗口内模拟和实验的散射分数相差不到2%。模拟和实验能谱在40至180 keV之间非常吻合。这些结果证明了GATE在模拟原始探测器设计方面的能力和灵活性。GATE的主要缺点在于它需要较长的计算时间：目前GEANT4和GATE合作团队正在研究这个问题。
