arXiv:2504.19155physics.med-phcs.AI2025-04被引 2

用机器学习精准模拟X射线束的阳极效应,减少实验校准量。

Machine Learning-Based Modeling of the Anode Heel Effect in X-ray Beam Monte Carlo Simulations

  • 用梯度提升回归模型预测阳极-阴极方向的强度分布。
  • 误差低于5%,仅需每能级6个探测点,减少65%测量量。
  • 适合临床剂量学、成像质量评估等需要真实束流建模的场景。

为在蒙特卡洛模拟中准确建模X射线成像系统的阳极效应,本文提出基于机器学习的框架,实现低实验校准需求下的真实束流强度分布。通过实验获取不同管电压下的束流权重,训练多种回归模型以预测阳极-阴极轴向的空间强度变化,这些权重捕捉了阳极效应引入的不对称性。建立系统性微调协议,在保持模型精度的同时最小化测量数量。模型集成至OpenGATE 10和GGEMS蒙特卡洛工具包,评估其可行性与预测性能。在所有测试模型中,梯度提升回归(GBR)表现最佳,各能量水平下预测误差均低于5%。优化后的微调策略仅需每能级6个探测位置,测量工作量减少65%,微调引入的最大误差低于2%。蒙特卡洛模拟中的剂量演员对比显示,基于GBR的模型能精确复现临床束流特性,显著优于传统对称束模型。本研究提供了一种鲁棒且可推广的方法,利用机器学习实现能量依赖的阳极效应建模,大幅降低校准数据需求,提升临床剂量学、图像质量评估与辐射防护仿真中的真实性。

原文摘要 · Abstract (English)

To develop a machine learning-based framework for accurately modeling the anode heel effect in Monte Carlo simulations of X-ray imaging systems, enabling realistic beam intensity profiles with minimal experimental calibration. Multiple regression models were trained to predict spatial intensity variations along the anode-cathode axis using experimentally acquired weights derived from beam measurements across different tube potentials. These weights captured the asymmetry introduced by the anode heel effect. A systematic fine-tuning protocol was established to minimize the number of required measurements while preserving model accuracy. The models were implemented in the OpenGATE 10 and GGEMS Monte Carlo toolkits to evaluate their integration feasibility and predictive performance. Among the tested models, gradient boosting regression (GBR) delivered the highest accuracy, with prediction errors remaining below 5% across all energy levels. The optimized fine-tuning strategy required only six detector positions per energy level, reducing measurement effort by 65%. The maximum error introduced through this fine-tuning process remained below 2%. Dose actor comparisons within Monte Carlo simulations demonstrated that the GBR-based model closely replicated clinical beam profiles and significantly outperformed conventional symmetric beam models. This study presents a robust and generalizable method for incorporating the anode heel effect into Monte Carlo simulations using machine learning. By enabling accurate, energy-dependent beam modeling with limited calibration data, the approach enhances simulation realism for applications in clinical dosimetry, image quality assessment, and radiation protection.

机器学习蒙特卡洛模拟医学成像剂量学

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