Biophysics Department, GSI Helmholtz Center for Heavy Ions Research, Planckstraße 1, Darmstadt, Germany.
J Radiat Res. 2012 Jul;53(4):620-7. doi: 10.1093/jrr/rrs007. Epub 2012 Jun 5.
We measured the physical and radiobiological characteristics of 1 GeV protons for possible applications in stereotactic radiosurgery (image-guided plateau-proton radiosurgery). A proton beam was accelerated at 1 GeV at the Brookhaven National Laboratory (Upton, NY) and a target in polymethyl methacrylate (PMMA) was used. Clonogenic survival was measured after exposures to 1-10 Gy in three mammalian cell lines. Measurements and simulations demonstrate that the lateral scattering of the beam is very small. The lateral dose profile was measured with or without the 20-cm plastic target, showing no significant differences up to 2 cm from the axis A large number of secondary swift protons are produced in the target and this leads to an increase of approximately 40% in the measured dose on the beam axis at 20 cm depth. The relative biological effectiveness at 10% survival level ranged between 1.0 and 1.2 on the beam axis, and was slightly higher off-axis. The very low lateral scattering of relativistic protons and the possibility of using online proton radiography during the treatment make them attractive for image-guided plateau (non-Bragg peak) stereotactic radiosurgery.
我们测量了 1GeV 质子的物理和放射生物学特性，以便将其可能应用于立体定向放射外科（图像引导平台质子放射外科）。质子束在布鲁克海文国家实验室（纽约尤顿）以 1GeV 的速度加速，使用聚甲基丙烯酸甲酯（PMMA）作为目标。在三种哺乳动物细胞系中，暴露于 1-10Gy 后测量集落存活。测量和模拟表明，光束的侧向散射非常小。在有或没有 20cm 塑料靶的情况下测量侧向剂量分布，在离轴 2cm 以内没有明显差异。在靶中产生了大量的次级快速质子，这导致在 20cm 深度的轴上测量的剂量增加了约 40%。在轴线上的 10%存活水平的相对生物效应在 1.0 到 1.2 之间，离轴略高。相对论质子的侧向散射非常低，并且在治疗过程中可以使用在线质子射线照相术，这使得它们成为图像引导平台（非布拉格峰）立体定向放射外科的有吸引力的选择。
