ABSTRACT

Purpose: x-ray contrast agents that contain iodine are commonly used for interventional and diagnostic procedures. To progress selective x-ray imaging, and discriminate the attenuating media, it is important to determine the absorption edge values and absorption features of the compounds used as contrast agents. For this purpose, μρ (mass attenuation coefficients), Zeff (effective atomic number) and Nel (electron density), which characterize the possibility of interaction with x-ray of iodine containing contrast agents (ICCAs: Iodixanol, Iohexol, Iopamidol, Iopromide, and Ioxagalete) were calculated using WinXCom code and Penelope Monte Carlo simulation programs. Materials and methods: Calculations were obtained in an energy range from 1keV to 1GeV. The values of Zeff and Nel were calculated using the µρ values of compounds. Variation in μρ, Zeff, and Nel values of the ICCAs were determined depend on x-ray energies. Results and discussion: It was determined that in the low energy region, where the probability of photoelectric absorption was high. In the intermediate energy region, where the compton scattering process occurs. Additionally, an increase was observed in the potential for pair production effect in the presence of high energy values. Moreover, since Z4-5 depended on the photoelectric effect, the cross-section significantly contributed to the Zeff values of the ICCAs; the highest values for Zeff and Nel were observed in low energy ranges. Furthermore, the results obtained from the two different code programs were similar to one another. Conclusion: The results of this study may be useful for determining the accuracy of the Zeff and Nel values of ICCAs using dual energy CT. As such, this research can contribute to developing a method for enhancing CT image quality.

摘要

目的：含碘的X射线造影剂通常用于介入和诊断程序。为了进行选择性X射线成像并区分衰减介质，重要的是确定用作造影剂的化合物的吸收边缘值和吸收特征。为此，μρ（质量衰减系数），Zeff（有效原子序数）和Nel（电子密度）表征了与含碘造影剂（ICCA：碘克沙醇，碘海醇，碘帕醇，碘普罗米德，和Ioxagalete）是使用WinXCom代码和Penelope Monte Carlo模拟程序计算的。材料和方法：在1keV至1GeV的能量范围内获得了计算结果。Zeff和Nel的值是使用化合物的µρ值计算的。ICCA的μρ，Zeff和Nel值的变化取决于X射线能量。结果和讨论：确定为在低能量区域中光电吸收的可能性高。在中间能量区域，发生康普顿散射过程。另外，在高能量值的存在下，观察到对产生配对的潜力的增加。此外，由于Z4-5依赖于光电效应，因此截面显着影响了ICCA的Zeff值。在低能量范围内观察到Zeff和Nel的最大值。此外，从两个不同的代码程序获得的结果彼此相似。结论：这项研究的结果对于使用双能CT确定ICCA的Zeff和Nel值的准确性可能有用。因此，这项研究可有助于开发一种增强CT图像质量的方法。