基于GATE的双平板正电子发射乳腺断层成像系统的仿真研究

采用Monte Carlo法仿真软件GATE,构建专用于乳腺成像的双平板正电子发射断层成像系统PEM并研究其性能。参考NEMA NU 4–2008标准,并在试验中略作改动。研究了PEM(positron emission mammography)的灵敏度、散射分数、晶体散射、计数率、固有空间分辨率等参数。结果表明,在350–650 keV能窗、6 cm平板间距下,系统灵敏度达14.17%,固有空间分辨率约1.2 mm;乳腺仿体活度为29.6 MBq时,噪声等效计数率NECR为1.508×105/s,满足PEM系统所需。

Simulation studies of flat-panel PEM detectors based on GATE

In this work,we used the GATE code to simulate a dual-head positron emission mammography(PEM) system using LYSO detectors and evaluate its performances.The NEMA NU 4-2008 standard,modified slightly,was referred for the PEM system.System performances of sensitivity,phantom scattering,crystal scattering,counting rate and intrinsic spatial resolution were simulated.A peak absolute sensitivity of 14.17%,intrinsic spatial resolution of 1.2 mm and the peak NEC rate of 1.508×105/s at an activity of 29.6 MBq in a breast phantom were found at a 350–650 keV energy window and 6 cm detector separation,meeting the system needs.