■要比较光子体积电弧治疗(VMAT)之间的计划质量,伽玛刀,和三种不同的质子束模式。
■计划使用三种不同质子斑点大小范围的回旋加速器产生的质子束,对20例患者的55个脑部病变进行了计划,CPB(光斑尺寸σ:2.7-7.0mm),直线加速器质子束,LPB(σ:2.9-5.5mm),和线性加速器质子微束,LPMBs(σ:0.9-3.9mm),有和没有孔,并与光子VMAT和伽玛刀计划进行比较。将每个质子和光子计划的每个损伤的剂量覆盖率设置为接收处方(Rx)剂量的GTV的99%。所有质子计划在稳健评估中使用±2mm的设置不确定度和±2%的范围不确定度,以实现GTV的V100%Rx>95%。将孔施用于照射■与CPB生成的计划相比,对于LPB和LPMB计划,平均CI和GI显著更好.基于光圈的IMPT计划显示,所有剂量测定指标均优于伽玛刀。与非基于孔径的计划相比,基于孔径的IMT计划还显示出浅层肿瘤(d<2.5cm)的所有剂量学指标的改善。
■LPB和LPMB是CPB或光子疗法的出色替代品,可显着增加对正常组织的保存。
UNASSIGNED: To compare plan quality among photon volumetric arc therapy (VMAT), Gamma Knife, and three different proton beam modalities.
UNASSIGNED: Fifty-five brain lesions from 20 patients were planned with three different proton spot size ranges of cyclotron-generated proton beams, CPBs (spot size σ: 2.7-7.0 mm), linear accelerator proton beams, LPBs (σ: 2.9-5.5 mm), and linear accelerator proton
minibeams, LPMBs (σ: 0.9-3.9 mm), with and without apertures and compared against photon VMAT and Gamma Knife plans. Dose coverage to each lesion for each proton and photon plan was set to 99% of the GTV receiving the prescription (Rx) dose. All proton plans used ±2 mm setup uncertainty and ±2% range uncertainty in robust evaluation to achieve V100%Rx > 95% of the GTV. Apertures were applied to proton beams irradiating tumors <1 cm3 volume and located <2.5 cm depth. Conformity index (CI), gradient index (GI), V12 Gy, V4.5 Gy, and mean brain dose were compared across all plan types. The Wilcoxon signed rank test was utilized to determine statistical significance of dosimetric results compared between photon and proton plans.
UNASSIGNED: When compared to CPB generated plans, average CI and GI were significantly better for the LPB and LPMB plans. Aperture-based IMPT plans showed improvement from Gamma Knife for all dosimetric metrics. Aperture-based IMPT plans also showed improvement in all dosimetric metrics for shallow tumors (d < 2.5 cm) when compared with non-aperture-based plans.
UNASSIGNED: The LPB and LPMB stand as excellent alternatives to CPB or photon therapy and significantly increase the preservation of normal tissue.