Colnot Julie, Mansour Imane Said, Schott Cathyanne, Martin Solène, Maury Pauline, Dijoud Thibault, Caliendo Mario, Couturier Maud, Deutsch Eric, Robert Charlotte
INSERM U1030, Université Paris-Saclay, Gustave Roussy, Villejuif, France; Radiotherapy department, Gustave Roussy, Villejuif, France; THERYQ, Rousset, France.
INSERM U1030, Université Paris-Saclay, Gustave Roussy, Villejuif, France; Radiotherapy department, Gustave Roussy, Villejuif, France.
Phys Med. 2025 Jul;135:105014. doi: 10.1016/j.ejmp.2025.105014. Epub 2025 Jun 2.
This study aimed to evaluate and validate the new FLASHKNiFE ultra-high dose rate (UHDR) radiotherapy system by commissioning and assessing the dosimetric performance of its electron UHDR beams to ensure accuracy and stability.
The FLASHKNiFE system is a mobile linear accelerator delivering UHDR electron beams (>40 Gy/s, 6 and 10 MeV) at various pulse repetition frequencies (10-250 Hz) and pulse widths (0.5-4 μs). Its dose monitoring system includes two independent current transformers for precise dose measurements. Performance tests were adapted from AAPM reports, IEC standards, and recent recommendations, focusing on repeatability, output stability, PDD curves, cross profiles, dose linearity, and the influence of UHDR parameters on dose distribution. Dose-independent detectors, such as radiochromic films and the FlashDiamond, ensured measurement accuracy.
Long-term output reproducibility was better than 5 %, and energy stability was within 2.5 %. PDD curves remained consistent within 1 mm. Delivered dose was proportional to pulse number and PW within 2 %, except for the lowest settings. Cross profiles met IEC standards for flatness and symmetry. Maximum axis doses for a 10-cm applicator were 1.3 Gy/pulse (10 MeV) and 1.1 Gy/pulse (6 MeV) at PW = 2 μs, achieving dose rates over 275 Gy/s. Dosimeter results were consistent within uncertainties.
The FLASHKNiFE system has been validated for preclinical studies, demonstrating robust, reproducible performance and providing a solid foundation for ongoing QA processes.
本研究旨在通过调试和评估其电子超高剂量率（UHDR）束流的剂量学性能，来评估和验证新型FLASHKNiFE超高剂量率放射治疗系统，以确保准确性和稳定性。
FLASHKNiFE系统是一台移动式直线加速器，可在不同的脉冲重复频率（10 - 250 Hz）和脉冲宽度（0.5 - 4 μs）下提供超高剂量率电子束（>40 Gy/s，6和10 MeV）。其剂量监测系统包括两个独立的电流互感器，用于精确的剂量测量。性能测试采用了美国医学物理师协会（AAPM）报告、国际电工委员会（IEC）标准和近期建议，重点关注重复性、输出稳定性、百分深度剂量（PDD）曲线、交叉剖面、剂量线性以及超高剂量率参数对剂量分布的影响。剂量独立探测器，如放射变色胶片和FlashDiamond，确保了测量的准确性。
长期输出再现性优于5%，能量稳定性在2.5%以内。PDD曲线在1 mm范围内保持一致。除最低设置外，输送剂量与脉冲数和脉冲宽度的比例在2%以内。交叉剖面符合IEC关于平坦度和对称性的标准。在脉冲宽度为2 μs时，10 cm施源器的最大轴剂量为1.3 Gy/脉冲（10 MeV）和1.1 Gy/脉冲（6 MeV），剂量率超过275 Gy/s。剂量计结果在不确定度范围内一致。
FLASHKNiFE系统已通过临床前研究验证，展示了强大、可重复的性能，并为正在进行的质量保证过程提供了坚实基础。
