High-resolution 3D Bayesian image reconstruction using the microPET small-animal scanner
High-resolution 3D Bayesian image reconstruction using the microPET small-animal scanner
复制标题
DOI：
10.1088/0031-9155/43/4/027
复制
发表时间：
1998-04-01
影响因子：
3.5
通讯作者：
Farquhar, TH
中科院分区：
文献类型：
--
作者：
Qi, JY;Leahy, RM;Farquhar, TH
贝叶斯方法被描述用于从microPET小动物扫描仪重建高分辨率3D图像。分辨率恢复是通过明确建模的深度相关的几何灵敏度为每个体素结合一个准确的探测器响应模型，包括由于光子对非共线性和晶体间散射和渗透的因素。为了减少存储和计算成本，我们使用一个分解矩阵，其中使用正弦图模糊内核对探测器响应进行建模。最大后验概率（MAP）图像重建使用该模型结合泊松似然函数和吉布斯先验的图像。使用精确的系统模型从点源数据获得的重建表明，与使用具有斜坡滤波器的解析3D重投影（3DRP）方法时的约2 mm相比，在所持视图的中心处的近各向同性FWHM分辨率约为1.2 mm的潜力。这些结果还表明，精确的系统模型能够补偿由于晶体穿透而导致的分辨率损失，从而产生1 mm到4 mm半径的几乎恒定的径向FWHM分辨率。在均匀圆柱体中点源的研究表明，由于图像的分辨率降低，以控制噪声传播，使用精确的系统模型获得的分辨率上级在匹配的背景噪声水平下使用3DRP获得的分辨率。使用直径为1-2.5 mm的热和冷圆柱体的饼状体模进行的其他研究和（18）FDG动物研究似乎证实了这一观察结果。
A Bayesian method is described for reconstruction of high-resolution 3D images from the microPET small-animal scanner. Resolution recovery is achieved by explicitly modelling the depth dependent geometric sensitivity for each voxel in combination with an accurate detector response model that includes factors due to photon pair non-collinearity and inter-crystal scatter and penetration. To reduce storage and computational costs we use a factored matrix in which the detector response is modelled using a sinogram blurring kernel. Maximum a posteriori (MAP) images are reconstructed using this model in combination with a Poisson likelihood function and a Gibbs prior on the image. Reconstructions obtained from point source data using the accurate system model demonstrate a potential for near-isotropic FWHM resolution of approximately 1.2 mm at the center of the held of view compared with approximately 2 mm when using an analytic 3D reprojection (3DRP) method with a ramp filter. These results also show the ability of the accurate system model to compensate for resolution loss due to crystal penetration producing nearly constant radial FWHM resolution of 1 mm out to a 4 mm radius. Studies with a point source in a uniform cylinder indicate that as the resolution of the image is reduced to control noise propagation the resolution obtained using the accurate system model is superior to that obtained using 3DRP at matched background noise levels. Additional studies using pie phantoms with hot and cold cylinders of diameter 1-2.5 mm and (18)FDG animal studies appear to confirm this observation.