Representation of photon limited data in emission tomography using origin ensembles
Representation of photon limited data in emission tomography using origin ensembles
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DOI：
10.1088/0031-9155/53/12/009
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发表时间：
2008-06-21
影响因子：
3.5
通讯作者：
Sitek, A.
中科院分区：
文献类型：
--
作者：
Sitek, A.
由于数据中的高噪声水平，由发射断层扫描仪获得的数据的表示和重建是具有挑战性的。通常，使用断层摄影测量获得的图像使用网格来表示。在这项工作中，我们定义的图像作为一组在断层测量检测到的事件的起源，我们称之为这些起源合奏（OE）。系综中的状态由3N个参数Y的向量表征，其中参数是三维空间中检测到的事件的原点的坐标，并且N是检测到的事件的数量。该合奏的3N维概率密度函数（PDF）的推导，我们提出了一种算法，从层析测量OE图像估计。可显示的图像（e. G.基于网格的图像）是通过使用马尔可夫链蒙特卡罗方法基于PDF计算集合期望而从OE公式导出的。该方法被应用到计算机模拟的3D列表模式正电子发射断层扫描数据。模拟的10 000 000事件采集的重建误差范围为0.1至34.8%，取决于对象的大小和采样密度。该方法也适用于实验数据和OE方法的结果是一致的，通过一个标准的最大似然法获得的。该方法是一种新的方法来表示和重建所获得的数据的光子限制发射断层扫描测量。
Representation and reconstruction of data obtained by emission tomography scanners are challenging due to high noise levels in the data. Typically, images obtained using tomographic measurements are represented using grids. In this work, we define images as sets of origins of events detected during tomographic measurements; we call these origin ensembles (OEs). A state in the ensemble is characterized by a vector of 3N parameters Y, where the parameters are the coordinates of origins of detected events in a three-dimensional space and N is the number of detected events. The 3N-dimensional probability density function (PDF) for that ensemble is derived, and we present an algorithm for OE image estimation from tomographic measurements. A displayable image ( e. g. grid based image) is derived from the OE formulation by calculating ensemble expectations based on the PDF using the Markov chain Monte Carlo method. The approach was applied to computer-simulated 3D list-mode positron emission tomography data. The reconstruction errors for a 10 000 000 event acquisition for simulated ranged from 0.1 to 34.8%, depending on object size and sampling density. The method was also applied to experimental data and the results of the OE method were consistent with those obtained by a standard maximum-likelihood approach. The method is a new approach to representation and reconstruction of data obtained by photon-limited emission tomography measurements.