Subramanian Narayani, Čolić Aleksandra, Santiago Franco Marina, Stolz Jessica, Ahmed Mabroor, Bicher Sandra, Winter Johanna, Lindner Rainer, Raulefs Susanne, Combs Stephanie E, Bartzsch Stefan, Schmid Thomas E
Department of Radiation Oncology, TUM School of Medicine and Health and Klinikum rechts der Isar, University Hospital of the Technical University of Munich, Ismaninger Straße 22, 81675 Munich, Germany.
Institute of Radiation Medicine (IRM), Helmholtz Zentrum, 85764 München, Germany.
Cancers (Basel). 2025 Jan 1;17(1):114. doi: 10.3390/cancers17010114.
The present study aimed to compare the tumor growth delay between conventional radiotherapy (CRT) and the spatially fractionated modalities of microbeam radiation therapy (MRT) and minibeam radiation therapy (MBRT). In addition, we also determined the influence of beam width and the peak-to-valley dose ratio (PVDR) on tumor regrowth.
A549, a human non-small-cell lung cancer cell line, was implanted subcutaneously into the hind leg of female CD1 mice. The animals were irradiated with sham, CRT, MRT, or MBRT. The spatially fractionated fields were created using two specially designed multislit collimators with a beam width of 50 μm and a center-to-center distance (CTC) of 400 μm for MRT and a beam width of 500 μm and 2000 μm CTC for MBRT. Additionally, the concept of the equivalent uniform dose (EUD) was chosen in our study. A dose of 20 Gy was applied to all groups with a PVDR of 20 for MBRT and MRT. Tumor growth was recorded until the tumors reached at least a volume that was at least three-fold of their initial value, and the growth delay was calculated.
We saw a significant reduction in tumor regrowth following all radiation modalities. A growth delay of 11.1 ± 8 days was observed for CRT compared to the sham, whereas MBRT showed a delay of 20.2 ± 7.3 days. The most pronounced delay was observed in mice irradiated with MRT PVDR 20, with 34.9 ± 26.3 days of delay.
The current study highlights the fact that MRT and MBRT modalities show a significant tumor growth delay in comparison to CRT at equivalent uniform doses.
本研究旨在比较传统放射治疗（CRT）与微束放射治疗（MRT）和迷你束放射治疗（MBRT）的空间分割模式之间的肿瘤生长延迟。此外，我们还确定了束宽和峰谷剂量比（PVDR）对肿瘤再生长的影响。
将人非小细胞肺癌细胞系A549皮下植入雌性CD1小鼠的后腿。对动物进行假照射、CRT、MRT或MBRT照射。使用两个专门设计的多缝准直器创建空间分割野，MRT的束宽为50μm，中心距（CTC）为400μm，MBRT的束宽为500μm，CTC为2000μm。此外，本研究采用了等效均匀剂量（EUD）的概念。对所有组施加20 Gy的剂量，MBRT和MRT的PVDR为20。记录肿瘤生长情况，直到肿瘤体积至少达到其初始值的三倍，并计算生长延迟。
我们发现所有放射治疗模式后肿瘤再生长均显著减少。与假照射相比，CRT观察到的生长延迟为11.1±8天，而MBRT显示延迟为20.2±7.3天。在用PVDR为20的MRT照射的小鼠中观察到最明显的延迟，延迟为34.9±26.3天。
当前研究突出了这样一个事实，即在等效均匀剂量下，与CRT相比，MRT和MBRT模式显示出显著的肿瘤生长延迟。
