自适应多叶光栅在脑肿瘤质子放疗中的应用

Application of adaptive aperture in proton radiotherapy for brain tumors

目的通过比较使用和不使用自适应多叶光栅的脑肿瘤质子调强治疗计划,评估自适应多叶光栅的临床应用价值。方法选取20例脑肿瘤术后行放射治疗的患者,在同样优化条件下为每位患者分别设计使用和不使用自适应多叶光栅的质子调强治疗计划,通过比较靶区适形指数(CI)、靶区均匀性指数(HI)和正常组织受量对两组方案进行评价。结果使用自适应多叶光栅设计质子调强治疗计划,靶区CI均值从0.58提高到0.66,50%处方剂量体积均值从797.70cm^(3)降低到638.15cm^(3),耳蜗、脑干、视交叉、视神经、眼晶状体的辐射受量均显著减少(t=2.06、3.02、2.11、2.58、2.67,P<0.05)。另外,两组方案间靶区的HI值以及计划的机器跳数差异没有统计学意义(P>0.05)。结论自适应多叶光栅能显著降低靶区周围正常组织的照射剂量,对保护靶区外危及器官具有积极作用,具有良好的临床应用前景。

Objective To evaluate the clinical application value of the adaptive aperture by comparing intensity-modulated proton radiotherapy(IMPT)plans using and not using the aperture for brain tumors.Methods A total of twenty patients treated with postoperative radiotherapy for brain tumors were enrolled in this study.IMPT plans were developed for each patient using and not using the adaptive aperture under the same optimization conditions.The target conformal index(CI)value,target homogeneity index(HI)value,and the dose to normal tissues of the two sets of plans were compared.Results The IMPT plans designed using the adaptive aperture significantly increased the mean CI value from 0.58 to 0.66,while decreasing the mean 50% prescription dose volume from 797.70 cm^(3) to 638.15 cm^(3).These plans also reduced the irradiation doses to the cochlea,brainstem,optic chiasm,optic nerve,and lens(t=2.06,3.02,2.11,2.58,2.67,P<0.05).Additionally,there was no significant difference in the HI value of the target volumes and the machine jumps(MU)between the two sets of plans(P>0.05).Conclusions The adaptive aperture can significantly reduce the irradiation dose to normal tissues outside the target volumes,positively impacting the protection of organs at risk(OARs)around the target values.This demonstrates its great potential for clinical application.