FAST CALCULATION OF THE EXACT RADIOLOGICAL PATH FOR A 3-DIMENSIONAL CT ARRAY
FAST CALCULATION OF THE EXACT RADIOLOGICAL PATH FOR A 3-DIMENSIONAL CT ARRAY
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DOI：
10.1118/1.595715
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发表时间：
1985-01-01
期刊：
影响因子：
3.8
通讯作者：
SIDDON, RL
中科院分区：
文献类型：
--
作者：
SIDDON, RL
计算机断层扫描（CT）数据在放射治疗中的各种应用已得到充分利用。例如，一些放射治疗计划系统现在在非均匀剂量计算算法中使用CT数据。在放射治疗成像应用中，CT数据被投射到指定平面上，从而产生x线片，这些x线片与模拟x线片进行比较，以帮助患者正确定位和描绘目标体积。所有这些应用都有一个共同的几何问题，即通过CT阵列评估放射路径。由于三维几何结构的复杂性和CT数据量的巨大，准确评估放射路径是一项耗时且困难的问题。本文指出了传统的精确评估放射路径的低效方面，因为它将CT数据视为单个体素。提出了一种新的考虑CT平面的精确算法，而不是单个体素。对于N3个体素的三维CT阵列，新的精确算法缩放为3N（平面数），而不是N3（体素数）。在带有浮点选项的VAX 11/780上用Fortran-77编码，该算法需要.apprx。计算1003体素阵列的平均辐射路径。
Ready availability has prompted the use of computed tomography (CT) data in various applications in radiation therapy. For example, some radiation treatment planning systems now utilize CT data in heterogeneous dose calculation algorithms. In radiotheraphy imaging applications, CT data are projected onto specified planes, thus producing radiographs, which are compared with simulator radiographs to assist in proper patient positioning and delineation of target volumes. All these applications share the common geometric problem of evaluating the radiological path through the CT array. Due to the complexity of the 3-dimensional geometry and the enormous amount of CT data, the exact evaluation of the radiological path has proven to be a time consuming and difficult problem. This paper identifies the inefficient aspect of the traditional exact evaluation of the radiological path as that of treating the CT data as individual voxels. Rather than individual voxels, a new exact algorithm is presented that considers the CT planes. For a 3-dimensional CT array of N3 voxels, the new exact algorithm scales with 3N, the number of planes, rather than N3, the number of voxels. Coded in Fortran-77 on a VAX 11/780 with a floating point option, the algorithm requires .apprx. 5 ms to calculate an average radiological path in a 1003 voxel array.