利用先进建模、详细模拟和精确质子布拉格曲线，提出液态水平均激发能的一致值
Proposal of a consistent value for the mean excitation energy of liquid water using advanced modeling, detailed simulations and precission proton Bragg curves
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中文总结 AI 辅助
本研究利用MELF-GOS与TDDFT-Penn两种方法，结合SEICS代码模拟质子布拉格曲线，确定液态水平均激发能$I=79.4$ eV，为质子治疗射程预测提供物理依据。
中文摘要 AI 辅助
质子治疗的精度取决于对液态水阻止本领的准确认知，因为液态水是人体软组织中含量最丰富的成分。由于处理挥发性液体时存在困难，关于液态水的阻止本领和平均激发能$I$值的争论已持续很久。液态水与无定形冰在所有临床相关质子能量下的单位质量密度阻止本领等价，这为获得液态水$I$值的可靠估计提供了可能。本研究采用两种互补的理论方法评估水的质子阻止本领：基于微扰介电形式论的MELF-GOS（Mermin能量损失函数-广义振子强度）方法，可作为足够高能量下的精确参考；新型非微扰TDDFT-Penn（含时密度泛函理论-Penn）方法，确保能量低于阻止本领峰值时仍能保持精度。将这些阻止本领值纳入模拟代码SEICS（高能离子与团簇在固体中的模拟），以评估1至230 MeV质子的布拉格曲线。与现有精确深度剂量测量结果的比较提供了关键见解，帮助确定液态水的一致值$I = 79.4$ eV，为改进治疗计划的射程预测提供了坚实物理基础。
英文摘要
Protontherapy precision depends on accurately knowing the stopping power of liquid water, as it is the most abundant component of soft body tissues. Difficulties when working with volatile liquids have led to a long-standing debate regarding the values of the stopping power and the mean excitation energy $I$ of liquid water. The equivalence between the stopping power of liquid water and amorphous ice per unit mass density across all clinically relevant proton energies opens the possibility to obtain a reliable estimation of the $I$-value of liquid water. In this work, we employ two complementary theoretical methodologies to assess the proton stopping power of water. The MELF-GOS (Mermin Energy Loss Function - Generalized Oscillator Strengths) approach, based on the perturbative dielectric formalism, serves as an accurate reference for sufficiently high energies, while the novel non-perturbative TDDFT-Penn (time-dependent density functional theory - Penn) method ensures accuracy for energies even below the stopping maximum. These stopping-power values were incorporated into the simulation code SEICS (Simulation of Energetic Ions and Clusters through Solids) to evaluate proton Bragg curves from $1$ to $230$ MeV. Comparisons with available precise depth-dose measurements provide critical insights that help establish the consistent value $I = 79.4$ eV for liquid water, providing robust physical grounds for improving range prediction for treatment planning.
