X-ray spectra estimation using attenuation measurements from 25 kVp to 18 MV
X-ray spectra estimation using attenuation measurements from 25 kVp to 18 MV
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DOI：
10.1118/1.598622
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发表时间：
1999-07-01
期刊：
影响因子：
3.8
通讯作者：
McDavid, WD
中科院分区：
文献类型：
--
作者：
Waggener, RG;Blough, MM;McDavid, WD
从25 kVp到18 MV的初级X射线光谱的衰减测量，除了使用铜过滤器的orthovoltage的所有能量使用铝过滤器。迭代扰动法，利用这些测量，推导出的表观X射线光谱。初始光谱或预光谱用于开始该过程。对预谱的每个能量值进行正和负扰动，并使用扰动值计算衰减曲线。选择给定能量箱中的X射线值，以使测量的透射曲线与计算的透射曲线之间的差异最小化。目标是使用导出的X射线光谱导出测量的透射曲线和计算的透射曲线之间的最小差异。该方法被发现产生有用的信息，较低的光子能量和实际操作电位与标称电位。乳腺摄影，诊断，orthovoltage，和兆伏X射线光谱高达18 MV标称使用这种方法。使用已发表文献中的衰减曲线对该方法进行了验证。该方法也验证了使用从公布的光谱计算的衰减曲线。然后使用衰减曲线导出X射线光谱。(C)1999年美国医学物理学家协会。[S0094-2405（99）00107-8]。
Attenuation measurements for primary x-ray spectra from 25 kVp to 18 MV were made using aluminum filters for all energies except for orthovoltage where copper filters were used. An iterative perturbation method, which utilized these measurements, was employed to derive the apparent x-ray spectrum. An initial spectrum or pre-spectrum was used to start the process. Each energy value of the pre-spectrum was perturbed positively and negatively, and an attenuation curve was calculated using the perturbed values. The value of x-rays in the given energy bin was chosen to minimize the difference between the measured and calculated transmission curves. The goal was to derive the minimum difference between the measured transmission curve and the calculated transmission curve using the derived x-ray spectrum. The method was found to yield useful information concerning the lower photon energy and the actual operating potential versus the nominal potential. Mammographic, diagnostic, orthovoltage, and megavoltage x-ray spectra up to 18 MV nominal were derived using this method. The method was Validated using attenuation curves from published literature. The method was also validated using attenuation curves calculated from published spectra. The attenuation curves were then used to derive the x-ray spectra. (C) 1999 American Association of Physicists in Medicine. [S0094-2405(99)00107-8].