Comparison of 3-D reconstruction with 3D-OSEM and with FORE plus OSEM for PET
Comparison of 3-D reconstruction with 3D-OSEM and with FORE plus OSEM for PET
复制标题
DOI：
10.1109/42.938248
复制
发表时间：
2001-08-01
影响因子：
10.6
通讯作者：
Townsend, D
中科院分区：
文献类型：
--
作者：
Liu, X;Comtat, C;Townsend, D
傅立叶反投影(FORE)和有序子集期望最大化(OSEM)这两种快速统计算法的结合，被认为是临床正电子发射断层扫描(PET)数据的全三维(3D)迭代方法的一种有前途的替代方法。在本文中，我们利用模拟和商用扫描仪获取的数据，评估了FORE+OSEM的性能，并将其与全三维OSEM进行了比较。目的是确定在有噪声的临床PET数据情况下，图像质量的下降在多大程度上弥补了FORE+OSEM的速度优势。基于线积分模型的正反投影对被用于二维OEM和三维OSEM(3D-OSEM)而不是系统矩阵。这两种方法的不同变体已经通过仿真在对比度-噪声折衷方面进行了研究。两种变种--FORE+OSEM加衰减加权(AW)[FORE+OSEM(AW)]和3D-OSEM加衰减归一化加权(ANSP)和平移泊松(SP)模型[3D-OSEM(ANSP)]--与测量的体模数据和患者数据进行了比较。根据模拟和测量数据的结果，我们得出结论：1)衰减(归一化)加权和SP模型都改善了图像质量，但减缓了收敛速度；2)尽管FORE+OSEM具有近似的性质，但对于具有典型全身FDG扫描噪声水平的数据，FORE+OSEM并没有显示出明显的图像退化。
The combination of Fourier rebinning (FORE) and the ordered subsets expectation-maximization (OSEM), a fast statistical algorithm, appears as a promising alternative to the fully three-dimensional (3-D) iterative approach for clinical positron emission tomography (PET) data. In this paper, we evaluated the properties of FORE+OSEM and compared it with fully 3-D OSEM using both simulations and data acquired by commercial scanners. The aim is to determine to what extent the speed advantage of FORE+OSEM is paid for by a possible degradation of image quality in the case of noisy clinical PET data.A forward- and back-projection pair based on a line integral model was used in two-dimensional OSEM and 3-D OSEM (3D-OSEM) instead of a system matrix. Different variants of both approaches have been studied with simulations in terms of contrast-noise tradeoff. Two variants-FORE+OSEM with attenuation weighting (AW) [FORE+OSEM(AW)] and 3D-OSEM with attenuation-normalization weighting (ANSP) and a shifted-Poisson (SP) model [3D-OSEM(ANSP)]-were compared with measured phantom data and patient data. Based on the results from both simulations and measured data, we conclude that: 1) both attenuation (-normalization) weighting and the SP model improve the image quality but slow down the convergence and 2) despite its approximate nature, FORE+OSEM does not show apparent image degradation compared with 3D-OSEM for data with a noise level typical of a whole-body FDG scan.