标题： 蒙特卡罗（DOSXYZnrc 和 VMC++）验证的广义坐标变换用于兼容 DICOM 的放疗计划 显示英文标题

标题： Generalized coordinate transformations for Monte Carlo (DOSXYZnrc and VMC++) verifications of DICOM compatible radiotherapy treatment plans

摘要： 国际电工委员会（IEC）之前已为放射治疗DICOM坐标系统中常用的正向机架、准直器和治疗床旋转定义了标准旋转算子。 已将坐标转换方法推导并发表在文献中，用于常见的蒙特卡罗（MC）代码（BEAMnrc/DOSXYZnrc和VMC++）。 然而，这些坐标转换忽略了在计算机断层扫描（CT）期间的患者体位，并假设最常用的“头先，仰卧”体位。 虽然较少见，但在临床上也会使用其他患者体位——由于缺乏适当的坐标转换，此类治疗的蒙特卡罗验证可能会出现问题。 在这项工作中，通过校正CT获得的幻影体位，并为DOSXYZnrc和VMC++代码中的场角推导出广义坐标转换，得到了解决方案。 使用DICOM图像方向标签（0020,0037）确定了包含任何可能患者治疗体位的旋转算子。 通过将蒙特卡罗剂量分布与Eclipse治疗计划系统计算的剂量分布进行比较，验证了患者图像和光束方向角的转换结果，该计算针对每种可能的八种患者体位进行。 显示英文摘要

摘要： The International Electrotechnical Commission (IEC) has previously defined standard rotation operators for positive gantry, collimator and couch rotations for the radiotherapy DICOM coordinate system that is commonly used by treatment planning systems. Coordinate transformations to the coordinate systems of commonly used Monte Carlo (MC) codes (BEAMnrc/DOSXYZnrc and VMC++) have been derived and published in the literature. However, these coordinate transformations disregard patient orientation during the computed tomography (CT) scan, and assume the most commonly used 'head first, supine' orientation. While less common, other patient orientations are used in clinics - Monte Carlo verification of such treatments can be problematic due to the lack of appropriate coordinate transformations. In this work, a solution has been obtained by correcting the CT-derived phantom orientation and deriving generalized coordinate transformations for field angles in the DOSXYZnrc and VMC++ codes. The rotation operator that includes any possible patient treatment orientation was determined using the DICOM Image Orientation tag (0020,0037). The derived transformations of the patient image and beam direction angles were verified by comparison of MC dose distributions with the Eclipse treatment planning system, calculated for each of the eight possible patient orientations.