多平行束准直器模拟研究

Simulation Study of Multi-parallel Beam Collimator

在平行束准直器中引用多通道技术设计了三通道的多平行束(Multi-parallel Beam,MPB)准直器。计算机模拟表明,MPB准直器在保持较高的空间分辨率下,有效地改善了系统的灵敏度。放射药物匀均分布的圆柱数字模具和Jaszczak数字模具(phantom)模拟表明,随重叠比例的增加,未出现重建环状伪影;虽然靠近准直器表面空间分辨率有所下降,但在FOV(Field of View)中心区域空间分辨率近似等同于平行束准直器,重建图像的匀均度有了改善。投影数据的重叠表明,MPB的投影有放大作用。该研究为高成像质量的临床SPECT成像提供一种新的准直器设计方法。

Multi-parallel beam（MPB） collimator with three channels was designed by introducing the multiplexing.The simulation study indicates that the system sensitivity is improved while maintaining a higher spatial resolution.The simulation of uniform cylinder phantom indicates that reconstructed ring artifacts are not appeared in reconstructed image as iterative number increasing.The simulation of Jaszczak phantom indicates that the spatial resolution of MPB collimator gradually approaches to the parallel-beam as depth increasing although the resolution descends near the collimator front face.The uniformity of reconstructed image is improved.The overlapping of projection data indicates that there is projection amplification for the MPB collimator.This study provides a way to design high quality SPECT image.