A silver nitrate (AgNO3) gel was developed and evaluated as a dosimeter for synchrotron X-ray-based studies in microbeam radiation therapy (MRT) and FLASH radiation therapy. The gel was irradiated at the European Synchrotron Radiation Facility (ID17 Biomedical beamline) with a continuous X-ray spectrum in the 50–600 keV range and a dose rate of 11.6 kGy/s. The spectrophotometric response after irradiation at this beamline was compared with the response at a conventional 60Co γ-ray source providing a dose rate of 0.27 Gy/s. Ag + ions in the gel dosimeter undergo reduction to Ago nanoparticles, as detected at 450 nm, which is a surface plasmon resonance band. The intensity of this band increased linearly with increasing absorbed dose up to 100 Gy, and improved with the addition of glycerol. The gel dosimeter exhibited the lowest detectable dose (LDD) of 75.9% lower and a dose deposition of 76% higher for ID17 beamline irradiation than for 60Co irradiation. The theoretical relative response HQ,Qo for the gel irradiated at the synchrotron was 1.70, which is in close agreement with the experimental relative response FQ,Qo = 1.76. These results confirm the dose enhancement in the gel irradiated with orthovoltage X-rays. The good properties of the silver nitrate gel, together with its increased sensitivity to orthovoltage X-ray irradiation and modest overall uncertainty of 5.8% (2σ), confirm that the gel is a valid dosimeter for measurements at ultrahigh dose rates for synchrotron radiotherapy. The dosimeter is also a promising candidate for dose enhancement factor measurements in nanoparticle-based radiotherapy techniques.

中文翻译：

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与 60Co γ射线相比，基于 Ag 纳米颗粒的凝胶剂量计在超高剂量率下同步辐射 X 射线在放射治疗中的应用研究


开发并评估了硝酸银 （AgNO3） 凝胶作为剂量计，用于微束放射治疗 （MRT） 和 FLASH 放射治疗中基于同步辐射 X 射线的研究。凝胶在欧洲同步辐射设施（ID17 生物医学光束线）以 50-600 keV 范围内的连续 X 射线光谱和 11.6 kGy/s 的剂量率进行照射。将该光束线照射后的分光光度响应与提供 0.27 Gy/s 剂量率的常规 60Co γ 射线源的响应进行了比较。凝胶剂量计中的 Ag + 离子被还原为 Ago 纳米颗粒，如 450 nm 处检测到的那样，这是表面等离子体共振带。该条带的强度随着吸收剂量的增加而线性增加，最高可达 100 Gy，并随着甘油的加入而改善。与 60Co 辐照相比，凝胶剂量计在 ID17 光束线照射下表现出最低可检测剂量 （LDD），低 75.9%，剂量沉积高 76%。在同步加速器照射的凝胶的理论相对响应 HQ，Qo 为 1.70，这与实验相对响应 FQ，Qo = 1.76 非常吻合。这些结果证实了用正压 X 射线照射的凝胶中的剂量增加。硝酸银凝胶的良好特性，以及它对正压 X 射线照射的更高灵敏度和 5.8% （2σ） 的适度总体不确定性，证实了该凝胶是一种有效的剂量计，用于同步辐射放疗的超高剂量率测量。剂量计也是基于纳米颗粒的放疗技术中剂量增强因子测量的有前途的候选者。