非小细胞肺癌光子调强适形放疗与质子调强适形放疗的剂量学比较

Dosimetric comparison of intensity-modulated photon radiotherapy and intensity-modulated proton radiotherapy for non-small cell lung cancer

目的:探讨非小细胞肺癌患者光子调强适形放疗(IMRT)与质子调强适形放疗(IMPT)剂量分布的差异性。方法:回顾性分析2020年11月至2022年4月中国科学技术大学附属第一医院离子医学中心收治的8例行放疗的Ⅱ~Ⅲ期非小细胞肺癌患者的临床资料,对每例患者分别进行IMRT及IMPT计划设计,主要评价指标有靶区剂量分布参数[均匀性指数(HI)、适形度指数(CI)、靶区中95%及100%处方剂量曲线包绕体积的百分体积(V_(95%)和V_(100%))]以及危及器官的平均剂量(D mean)和一定相对生物效应(RBE)剂量照射百分体积[患侧肺D_(mean)、V_(5)Gy(RBE)和V_(20)Gy(RBE),双肺D_(mean)、V_(5)Gy(RBE)和V_(20)Gy(RBE),心脏D_(mean)、V_(30) Gy(RBE)、V_(40)Gy(RBE),脊髓最大剂量(D_(max)),食管D mean]。 结果:与IMRT比较,IMPT可以降低双肺、患侧肺、脊髓、食管以及心脏的剂量参数水平,差异均有统计学意义(均 P<0.05),特别是双肺D_(mean)[(4.1±1.8)Gy(RBE)比(6.9±1.9)Gy(RBE)]、V_(5)Gy(RBE)[(15.9±7.1)%比(28.5±8.6)%]、V_(20)Gy(RBE)[(7.4±3.5)%比(10.1±3.5)%]以及患侧肺D mean[(9.1±4.5)Gy(RBE)比(11.9±3.3)Gy(RBE)]均下降明显(均 P<0.001),但二者间靶区剂量分布参数水平差异均无统计学意义(均 P>0.05)。 结论:对于非小细胞肺癌患者,IMPT在双肺、患侧肺、脊髓、食管以及心脏的保护方面均优于IMRT。

ObjectiveTo investigate the difference of dose distribution between intensity-modulated photon radiotherapy(IMRT)and intensity-modulated proton radiotherapy(IMPT)in patients with non-small cell lung cancer.MethodsThe clinical data of 8 patients with stageⅡ-Ⅲnon-small cell lung cancer who received radiotherapy in Ion Medical center of the First Affiliated Hospital of University of Science and Technology of China from November 2020 to April 2022 were retrospectively analyzed.IMRT and IMPT radiotherapy plans were created for each patient separately,the main evaluation indicators were targeted area dose distribution parameters[homogeneity index(HI),conformity index(CI)and the percent volume of volume wrapped by 95% and 100% of prescription dose profile in the targeted area(V95%and V100%)],and the average dose(D_(mean))to the organ at risk and the percent volume of a certain relative biological effect(RBE)dose exposure[D_(mean),V5 Gy(RBE)and V20 Gy(RBE)of ipsilateral lung,D_(mean),V5 Gy(RBE)and V20 Gy(RBE)of bilateral lung,Dmean,V30 Gy(RBE)and V40 Gy(RBE)of heart,maximum dose(D_(max))of spinal cord,and Dmean of esophageal].ResultsIn comparison with IMRT,IMPT reduced the levels of dose parameters in bilateral lung,ipsilateral lung,spinal cord,esophagus,and heart with statistically significant differences(all P<0.05),especially in D mean of bilateral lung[(4.1±1.8)Gy(RBE)vs.(6.9±1.9)Gy(RBE)],V5 Gy(RBE)[(15.9±7.1)%vs.(28.5±8.6)%],V20 Gy(RBE)[(7.4±3.5)%vs.(10.1±3.5)%],and D_(mean) of ipsilateral lung[(9.1±4.5)Gy(RBE)vs.(11.9±3.3)Gy(RBE)],all decreased significantly(allP<0.001),but the differences in the levels of targeted area dose distribution parameters between them were not statistically significant(all P>0.05).ConclusionsFor patients with non-small cell lung cancer,IMPT is superior to IMRT in the protection of bilateral lung,ipsilateral lung,spinal cord,esophagus and heart.