A deeper understanding of biological mechanisms to promote more efficient treatment strategies in proton therapy demands advances in preclinical radiation research. However this is often limited by insufficient availability of adequate infrastructures for precision image guided small animal proton irradiation. The project SIRMIO aims at filling this gap by developing a portable image-guided research platform for small animal irradiation, to be used at clinical facilities and allowing for a precision similar to a clinical treatment, when scaled down to the small animal size. This work investigates the achievable dosimetric properties of different lowest energy clinical proton therapy beams, manipulated by a dedicated portable beamline including active focusing after initial beam energy degradation and collimation. By measuring the lateral beam size in air close to the beam nozzle exit and the laterally integrated depth dose in water, an analytical beam model based on the beam parameters of the clinical beam at the Rinecker Proton Therapy Center was created for the lowest available clinical beam energy. The same approach was then applied to estimate the lowest energy beam model of different proton therapy facilities, Paul Scherrer Institute, Centre Antoine Lacassagne, Trento Proton Therapy Centre and the Danish Centre for Particle Therapy, based on their available beam commissioning data. This comparison indicated similar beam properties for all investigated sites, with emittance values of a few tens of mmmrad. Finally, starting from these beam models, we simulated propagation through a novel beamline designed to manipulate the beam energy and size for precise small animal irradiation, and evaluated the resulting dosimetric properties in water. For all investigated initial clinical beams, similar dosimetric results suitable for small animal irradiation were found. This work supports the feasibility of the proposed SIRMIO beamline, promising suitable beam characteristics to allow for precise preclinical irradiation at clinical treatment facilities.

更深入地了解促进质子治疗中更有效治疗策略的生物学机制需要临床前放射研究的进展。然而，这通常受到用于精确图像引导的小动物质子辐照的足够基础设施的不足的限制。SIRMIO 项目旨在通过开发用于小动物照射的便携式图像引导研究平台来填补这一空白，该平台可用于临床设施，并在缩小到小动物尺寸时允许类似于临床治疗的精度。这项工作研究了不同最低能量临床质子治疗光束的可实现剂量特性，由专用便携式光束线操纵，包括初始光束能量退化和准直后的主动聚焦。通过测量靠近射束喷嘴出口的空气中的横向射束尺寸和水中的横向综合深度剂量，基于 Rinecker 质子治疗中心临床射束的射束参数，为可用的最低临床射束创建了分析射束模型活力。然后，根据可用的束流调试数据，应用相同的方法来估计不同质子治疗设施、Paul Scherrer 研究所、Antoine Lacassagne 中心、Trento 质子治疗中心和丹麦粒子治疗中心的最低能量束模型。这种比较表明所有研究地点的光束特性相似，发射度值为几十毫米拉德。最后，从这些梁模型开始，我们模拟了通过一种新型光束线的传播，该光束线旨在操纵光束能量和尺寸以进行精确的小动物照射，并评估了在水中产生的剂量学特性。对于所有研究的初始临床射束，发现了适用于小动物照射的类似剂量测定结果。这项工作支持了所提出的 SIRMIO 光束线的可行性，承诺了合适的光束特性，以允许在临床治疗设施中进行精确的临床前照射。