A parametrization of the CT number of a substance and its use for stoichiometric calibration
A parametrization of the CT number of a substance and its use for stoichiometric calibration
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DOI：
10.1016/j.ejmp.2011.02.001
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发表时间：
2012-01-01
影响因子：
3.4
通讯作者：
Manzanas, Maria J.
中科院分区：
文献类型：
--
作者：
Martinez, Luis C.;Calzado, Alfonso;Manzanas, Maria J.
提出了一种对放射治疗计划中使用的 CT 扫描仪进行化学计量校准的方法。该方法基于物质 CT 数的简单参数化，仅涉及两个描述物质的变量（电子密度和一个有效原子序数）和一个描述光束的参数。该方法在一组梁上进行了实验测试。采用一组已知密度和元素组成的非组织样物质作为校准物。使用所提出的参数化计算 CT 数-密度曲线（红色曲线），并与使用商业密度体模测量的曲线进行比较。计算的 RED 曲线与测量的电子密度之间的差异在 0.009-0.019 (RMS) 范围内。所提出的方法可用于通过仅使用一种合适的物质作为校准物（不一定是组织样物质）来执行精确的化学计量校准。 (C) 2011 年意大利医疗协会。由爱思唯尔有限公司出版。保留所有权利。
A method to carry out stoichiometric calibrations of CT scanners employed in radiotherapy treatment planning is proposed. The method is based on a simple parametrization of the CT number of a substance, which involves only two variables to describe the substance (electron density and one effective atomic number) and one parameter to describe the beam. The method was tested experimentally on a group of beams. A set of no tissue-like substances of known densities and elemental compositions were employed as calibrators. CT number-to-density curves (RED curves) were calculated with the proposed parametrization and compared to those measured with a commercial density phantom. Differences between the electron densities assigned by the calculated RED curves and the measured ones were in the range 0.009-0.019 (RMS). The proposed method may be employed to carry out accurate stoichiometric calibrations by using only one suitable substance as calibrator, not necessarily tissue-like. (C) 2011 Associazione ltaliana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.