Mori Yutaro, Isobe Tomonori, Ide Yasuwo, Uematsu Shuto, Tomita Tetsuya, Nagai Yoshiaki, Iizumi Takashi, Takei Hideyuki, Sakurai Hideyuki, Sakae Takeji
Institute of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
Graduate School of Comprehensive Human Sciences, Degree Programs in Comprehensive Human Sciences, Doctoral Program in Medical Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
Phys Eng Sci Med. 2024 Dec;47(4):1665-1676. doi: 10.1007/s13246-024-01479-w. Epub 2024 Sep 9.
In recent years, eye lens exposure among radiation workers has become a serious concern in medical X-ray fluoroscopy and interventional radiology (IVR), highlighting the need for radiation protection education and training. This study presents a method that can maintain high accuracy when calculating spatial dose distributions obtained via Monte Carlo simulation and establishes another method to three-dimensionally visualize radiation using the obtained calculation results for contributing to effective radiation-protection education in X-ray fluoroscopy and IVR. The Monte Carlo particle and heavy ion transport code system (PHITS, Ver. 3.24) was used for calculating the spatial dose distribution generated by an angiography device. We determined the peak X-ray tube voltage and half value layer using Raysafe X2 to define the X-ray spectrum from the source and calculated the X-ray spectrum from the measured results using an approximation formula developed by Tucker et al. Further, we performed measurements using the "jungle-gym" method under the same conditions as the Monte Carlo calculations for verifying the accuracy of the latter. An optically stimulated luminescence dosimeter (nanoDot dosimeter) was used as the measuring instrument. In addition, we attempted to visualize radiation using ParaView (version 5.12.0-RC2) using the spatial dose distribution confirmed by the above calculations. A comparison of the measured and Monte Carlo calculated spatial dose distributions revealed that some areas showed large errors (12.3 and 24.2%) between the two values. These errors could be attributed to the scattering and absorption of X-rays caused by the jungle gym method, which led to uncertain measurements, and (2) the angular and energy dependencies of the nanoDot dosimetry. These two causes explain the errors in the actual values, and thus, the Monte Carlo calculations proposed in this study can be considered to have high-quality X-ray spectra and high accuracy. We successfully visualized the three-dimensional spatial dose distribution for direct and scattered X-rays separately using the obtained spatial dose distribution. We established a method to verify the accuracy of Monte Carlo calculations performed through the procedures considered in this study. Various three-dimensional spatial dose distributions were obtained with assured accuracy by applying the Monte Carlo calculation (e.g., changing the irradiation angle and adding a protective plate). Effective radiation-protection education can be realized by combining the present method with highly reliable software to visualize dose distributions.
近年来，辐射工作人员的晶状体暴露问题在医学X射线荧光检查和介入放射学（IVR）中已成为一个严重关切的问题，这凸显了辐射防护教育和培训的必要性。本研究提出了一种在计算通过蒙特卡罗模拟获得的空间剂量分布时能够保持高精度的方法，并建立了另一种方法，利用所获得的计算结果对X射线荧光检查和IVR中的辐射进行三维可视化，以促进有效的辐射防护教育。蒙特卡罗粒子与重离子输运代码系统（PHITS，版本3.24）用于计算血管造影设备产生的空间剂量分布。我们使用Raysafe X2确定峰值X射线管电压和半值层，以定义来自源的X射线光谱，并使用Tucker等人开发的近似公式根据测量结果计算X射线光谱。此外，我们在与蒙特卡罗计算相同的条件下使用“攀爬架”方法进行测量，以验证后者的准确性。使用光激发发光剂量计（nanoDot剂量计）作为测量仪器。此外，我们尝试使用ParaView（版本5.12.0-RC2），根据上述计算确认的空间剂量分布对辐射进行可视化。测量的空间剂量分布与蒙特卡罗计算结果的比较表明，某些区域在两者之间显示出较大误差（12.3%和24.2%）。这些误差可能归因于：（1）“攀爬架”方法导致X射线的散射和吸收，从而导致测量不确定；（2）nanoDot剂量测定法的角度和能量依赖性。这两个原因解释了实际值中的误差，因此，本研究中提出的蒙特卡罗计算可被认为具有高质量的X射线光谱和高精度。我们利用所获得的空间剂量分布成功地分别对直接X射线和散射X射线的三维空间剂量分布进行了可视化。我们建立了一种方法来验证通过本研究中所考虑的程序进行的蒙特卡罗计算的准确性。通过应用蒙特卡罗计算（例如，改变照射角度和添加防护板），可以获得各种具有确定精度的三维空间剂量分布。将本方法与高度可靠的软件相结合以可视化剂量分布，可实现有效的辐射防护教育。
