Microbeam radiation therapy (MRT), a preclinical form of spatially fractionated radiotherapy, uses an array of microbeams of hard synchrotron X-ray radiation. Recently, compact synchrotron X-ray sources got more attention as they provide essential prerequisites for the translation of MRT into clinics while overcoming the limited access to synchrotron facilities. At the Munich compact light source (MuCLS), one of these novel compact X-ray facilities, a proof of principle experiment was conducted applying MRT to a xenograft tumor mouse model. First, subcutaneous tumors derived from the established squamous carcinoma cell line FaDu were irradiated at a conventional X-ray tube using broadbeam geometry to determine a suitable dose range for the tumor growth delay. For irradiations at the MuCLS, FaDu tumors were irradiated with broadbeam and microbeam irradiation at integral doses of either 3 Gy or 5 Gy and tumor growth delay was measured. Microbeams had a width of 50 µm and a center-to-center distance of 350 µm with peak doses of either 21 Gy or 35 Gy. A dose rate of up to 5 Gy/min was delivered to the tumor. Both doses and modalities delayed the tumor growth compared to a sham-irradiated tumor. The irradiated area and microbeam pattern were verified by staining of the DNA double-strand break marker γH2AX. This study demonstrates for the first time that MRT can be successfully performed in vivo at compact inverse Compton sources.

中文翻译：

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在慕尼黑紧凑型光源上进行微束放射治疗的原理性实验证明。

微束放射疗法（MRT）是空间分割放射疗法的临床前形式，它使用硬同步辐射X射线放射的微束阵列。近年来，紧凑的同步加速器X射线源受到了越来越多的关注，因为它们为将MRT转换为诊所提供了必要的先决条件，同时又克服了对同步加速器设施的限制。在这些新型紧凑X射线设备之一的慕尼黑紧凑型光源（MuCLS）上，将MRT应用于异种移植肿瘤小鼠模型进行了原理验证实验。首先，将来自已建立的鳞状癌细胞系FaDu的皮下肿瘤用宽束几何结构在常规X射线管上照射，以确定适合肿瘤生长延迟的剂量范围。对于在MuCLS上的照射，用3 Gy或5 Gy的完整剂量的宽束和微束辐照FaDu肿瘤，并测量肿瘤生长延迟。微束的宽度为50 µm，中心距为350 µm，峰值剂量为21 Gy或35 Gy。高达5 Gy / min的剂量率被递送至肿瘤。与假照射的肿瘤相比，剂量和方式都延迟了肿瘤的生长。通过DNA双链断裂标记γH2AX的染色来验证照射面积和微束图案。这项研究首次证明，在紧凑型逆康普顿源体内可以成功进行MRT。高达5 Gy / min的剂量率被递送至肿瘤。与假照射的肿瘤相比，剂量和方式都延迟了肿瘤的生长。通过DNA双链断裂标记γH2AX的染色来验证照射面积和微束图案。这项研究首次证明，在紧凑型逆康普顿源体内可以成功进行MRT。高达5 Gy / min的剂量率被递送至肿瘤。与假照射的肿瘤相比，剂量和方式都延迟了肿瘤的生长。通过DNA双链断裂标记γH2AX的染色来验证照射面积和微束图案。这项研究首次证明，在紧凑型逆康普顿源体内可以成功进行MRT。