公开(公告)号：US20030190065A1

公开(公告)日：2003-10-09

申请号：US10397597

申请日：2003-03-26

申请人： CTI PET Systems, Inc.

发明人： James J. Hamill ,  Christian J. Michel

IPC分类号： G01T005/00

CPC分类号： G01T1/2985

摘要： A method for performing accurate iterative reconstruction of image data sets based on Approximate Discrete Radon Transformation (ADRT). ADRT and its inverse are implemented to provide exactly matched forward and backward projectors suitable for the Maximum-Likelihood Expectation-Maximization (ML-EM) reconstruction in PET. A 2D EM reconstruction algorithm is accomplished by initializing an estimation image. A back projection of the projection weights is then formed. A loop is begun with a controlled number of iterations. The estimated image is then forward projected using linogram coordinates. A correction ratio linogram is formed and correction factors are back projected. A normalization factor is then applied. This 2D EM method is extendable into 3D reconstructions using 3D PET lines of response. Forward projection is performed on planes extracted from the image voxels. Back projection is also performed in 2D planes, which are subsequently added into the 3D array with the correct orientations.

摘要翻译： 一种基于近似离散氡变换（ADRT）对图像数据集执行精确迭代重建的方法。 实现了ADRT及其逆向提供精确匹配的向前和向后投影机，适用于PET中的最大似然预期最大化（ML-EM）重建。 通过初始化估计图像来实现2D EM重建算法。 然后形成投影重物的背投。 一个循环以受控数量的迭代开始。 然后使用线绘图坐标向前投影估计的图像。 形成校正比例线性图，并且校正因子被反映出来。 然后应用归一化因子。 这种2D EM方法可以使用3D PET线的响应扩展到3D重建中。 在从图像体素提取的平面上进行前向投影。 背投影也在2D平面中进行，随后将其以正确的方向添加到3D阵列中。

公开(公告)号：US20030178559A1

公开(公告)日：2003-09-25

申请号：US10103276

申请日：2002-03-21

申请人： CTI PET Systems, Inc.

发明人： James J. Hamill ,  Michael E. Casey ,  Timothy G. Gremillion ,  Wing K. Luk ,  Stephen Miller

IPC分类号： G01T001/166

CPC分类号： G01T1/2985 ,  A61B6/037 ,  G01T1/1644

摘要： Apparatus and methods for simulating a sheet source with a line source for determining normalization coefficients for the detectors in positron emission tomography (PET) scanners and single photon emission computed tomography (SPECT) scanners. A line source, oriented perpendicular to the axis of a scanner gantry, is moved along the axis while the detectors are stationary and positioned substantially parallel to the plane in which the source moves. In another embodiment, an axially mounted line source moves parallel to a diameter of the gantry while the stationary detectors are positioned substantially parallel to the plane in which the source moves. In still another embodiment, the line source is stationary and positioned parallel to the gantry axis and off center while the detectors move relative to the line source. A shaped attenuator is placed around the source in this last embodiment.

摘要翻译： 用于模拟具有用于确定正电子发射断层摄影（PET）扫描仪和单光子发射计算机断层摄影（SPECT）扫描仪中的检测器的归一化系数的线源的片材源的装置和方法。 垂直于扫描仪台架的轴线定向的线源沿轴线移动，同时检测器是固定的并且基本上平行于源移动的平面定位。 在另一个实施例中，轴向安装的线源平行于台架的直径移动，而固定检测器基本上平行于源移动的平面定位。 在另一个实施例中，线源固定并且平行于台架轴定位并且离开中心，同时检测器相对于线源移动。 在最后一个实施例中，围绕源设置成形的衰减器。

公开(公告)号：US20040206897A1

公开(公告)日：2004-10-21

申请号：US10418520

申请日：2003-04-18

申请人： CTI PET Systems, Inc.

发明人： Maurizio Conti ,  James J. Hamill ,  Michael E. Casey ,  Mu Chen

IPC分类号： G01T001/172

CPC分类号： G01T1/2985 ,  A61B6/037

摘要： A normalization apparatus and method for a PET scanner with panel detectors for obtaining an estimate of a normalization array, for correction for count rate effects on the normalization array, and for measurement of the relation between the normalization array and the count rate. The method of the present invention is based on two quasi-independent radial and axial components, which are count rate dependent due to sensitivity changes across the detector blocks. A scatter source is disposed at the center of the FOV and a scatter-free source is disposed at the outer edge of the FOV. The method computes the normalization array through several steps which evaluate the geometric profile, the axial profile, and the correction factor. A count rate correction is introduced to extend the normalization array to any count rate.

摘要翻译： 一种具有面板检测器的PET扫描仪的归一化装置和方法，用于获得归一化阵列的估计，用于校正对归一化阵列的计数率影响，以及用于测量归一化阵列与计数率之间的关系。 本发明的方法是基于两个准独立的径向和轴向分量，其由于检测器块两端的灵敏度变化而依次计数。 散射源设置在FOV的中心，并且不分散源设置在FOV的外边缘处。 该方法通过评估几何轮廓，轴向轮廓和校正因子的几个步骤来计算归一化阵列。 引入计数率校正以将归一化数组扩展到任何计数率。