Bahreyni Toossi M T, Islamian J Pirayesh, Momennezhad M, Ljungberg M, Naseri S H
Medical Physics Research Center, Mashhad University of Medical Sciences, Iran.
J Med Phys. 2010 Jan;35(1):42-7. doi: 10.4103/0971-6203.55967.
In this study, we simulated a Siemens E.CAM SPECT system using SIMIND Monte Carlo program to acquire its experimental characterization in terms of energy resolution, sensitivity, spatial resolution and imaging of phantoms using (99m)Tc. The experimental and simulation data for SPECT imaging was acquired from a point source and Jaszczak phantom. Verification of the simulation was done by comparing two sets of images and related data obtained from the actual and simulated systems. Image quality was assessed by comparing image contrast and resolution. Simulated and measured energy spectra (with or without a collimator) and spatial resolution from point sources in air were compared. The resulted energy spectra present similar peaks for the gamma energy of (99m)Tc at 140 KeV. FWHM for the simulation calculated to 14.01 KeV and 13.80 KeV for experimental data, corresponding to energy resolution of 10.01 and 9.86% compared to defined 9.9% for both systems, respectively. Sensitivities of the real and virtual gamma cameras were calculated to 85.11 and 85.39 cps/MBq, respectively. The energy spectra of both simulated and real gamma cameras were matched. Images obtained from Jaszczak phantom, experimentally and by simulation, showed similarity in contrast and resolution. SIMIND Monte Carlo could successfully simulate the Siemens E.CAM gamma camera. The results validate the use of the simulated system for further investigation, including modification, planning, and developing a SPECT system to improve the quality of images.
在本研究中，我们使用SIMIND蒙特卡罗程序模拟了西门子E.CAM单光子发射计算机断层扫描（SPECT）系统，以获取其在能量分辨率、灵敏度、空间分辨率以及使用（99m）锝对体模成像方面的实验特性。SPECT成像的实验和模拟数据是从一个点源和Jaszczak体模获取的。通过比较从实际系统和模拟系统获得的两组图像及相关数据来完成模拟验证。通过比较图像对比度和分辨率来评估图像质量。比较了模拟和测量的能谱（有无准直器）以及空气中点源的空间分辨率。所得能谱在140千电子伏特处呈现出与（99m）锝的γ能量相似的峰。模拟计算的半高宽为14.01千电子伏特，实验数据为13.80千电子伏特，与两个系统定义的9.9%相比，能量分辨率分别为10.01%和9.86%。实际和虚拟γ相机的灵敏度分别计算为85.11和85.39计数每秒每兆贝克勒尔。模拟和实际γ相机的能谱相匹配。从Jaszczak体模通过实验和模拟获得的图像在对比度和分辨率方面显示出相似性。SIMIND蒙特卡罗程序能够成功模拟西门子E.CAMγ相机。这些结果验证了使用模拟系统进行进一步研究的可行性，包括对SPECT系统进行修改、规划和开发以提高图像质量。
