ESTIMATION OF GEOMETRICAL PARAMETERS AND COLLIMATOR EVALUATION FOR CONE BEAM TOMOGRAPHY
ESTIMATION OF GEOMETRICAL PARAMETERS AND COLLIMATOR EVALUATION FOR CONE BEAM TOMOGRAPHY
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DOI：
10.1118/1.596505
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发表时间：
1990-03-01
期刊：
影响因子：
3.8
通讯作者：
HAGIUS, JT
中科院分区：
文献类型：
--
作者：
GULLBERG, GT;TSUI, BMW;HAGIUS, JT
提出了一种从360度以上的投影点源质心坐标估计圆锥光束探测器几何参数的方法。通过几何参数推导出质心坐标的非线性表达式，其几何参数包括：旋转中心在探测器图像平面上投影的二维坐标；焦距；从焦点到旋转中心的距离；以及点源本身的空间坐标。实验数据是用带对称会聚准直器的旋转伽玛相机获得的。采用马夸特算法估计了这种特殊锥束几何形状的参数。该方法能够估计准直器的几何参数，并对准直器的构造精度进行评价。
A method is presented for estimating the geometrical parameters for a cone beam detector geometry from the coordinates of the centroid of a projected point source sampled over 360.degree.. Nonlinear expressions are derived for the coordinates of the centroids in terms of the geometrical parameters which include: the two-dimensional coordinates of the projection of the center of rotation onto the detector image plane; the focal length; the distance from the focal point to the center of rotation; and the spatial coordinates of the point source itself. Experimental data were obtained using a rotating gamma camera with a symmetrically converging collimator. The Marquardt algorithm was used to estimate the parameters for this particular cone beam geometry. The method was able to estimate the geometrical parameters and evaluate the accuracy of the collimator construction.