非小细胞肺癌三维适形放射治疗与固定野动态调强放射治疗的剂量学比较

Dosimetric Differences Between Three Dimensional Conformal Radiotherapy and Fixed Field Dynamic Intensity Modulation Radiotherapy for Non-small Cell Lung Cancer

目的比较非小细胞肺癌(NSCLC)三维适形放射治疗(3D-CRT)与固定野动态调强放射治疗(dIMRT)的剂量学差异,探讨两种治疗方式的剂量学优势及应用特点。方法随机选取2019年1月至2021年12月于常德市第一人民医院接受放射治疗的14例Ⅰ~ⅢB期NSCLC患者,在平均密度投影(AIP)图像上分别行3D-CRT与dIMRT计划设计,比较两种计划的计划靶区(PTV)相关剂量学参数[D_(2%)、D_(50%)、D_(98%)、D_(mean)、V_(95%)、V_(100%)、V_(110%)、均匀性指数(HI)、适形度指数(CI)及梯度测量值(GM)]、危及器官(全肺、对侧肺、心脏、食管及脊髓)相关剂量学参数(V_(X)、D_(mean)、D_(max))、机器跳数(MU)及靶区外正常组织(NT)的受照射剂量。结果PTV相关剂量学参数方面,dIMRT计划的D_(2%)、D_(98%)、D_(mean)、V_(100%)、V_(110%)、HI、CI均优于3D-CRT计划,差异均有统计学意义(P<0.05)。危及器官相关剂量学参数方面,两种计划的全肺V_(5)、V_(30)、V_(40)、D_(mean),对侧肺的V_(5),心脏的V_(40)及脊髓的D_(mean)比较,差异均有统计学意义(P<0.05),其中3D-CRT计划的全肺和对侧肺V_(5)、脊髓D_(mean)优于dIMRT计划。3D-CRT计划的MU比IMRT计划平均减少了351.21,差异有统计学意义(P<0.05)。两种计划的NT、V_(5)、V_(30)、V_(35)、V_(40)、V_(45)和V_(50)比较,差异均有统计学意义(P<0.05)。结论3D-CRT与dIMRT应用于NSCLC的放射治疗中,均能满足临床需求,3D-CRT在低剂量控制(全肺、对侧肺、NT的V_(5))以及执行效率方面优于dIMRT,而dIMRT在靶区剂量分布、危及器官V_(30)和V_(40)及NT V_(30)~V_(50)调控方面更具优势,临床可根据具体情况灵活选择治疗方式。

Objective With the comparison of dosimetric differences between three-dimensional conformal radiotherapy(3D-CRT)and fixed field dynamic intensity modulated radiotherapy(dIMRT)for non-small cell lung cancer(NSCLC),the dosimetric advantages and application characteristics of the two treatment methods were investigated.Methods With the random selection of 14 NSCLC patients of stage Ⅰ~ⅢB received radiotherapy in The First People's Hospital of Changde City from January 2019 to December 2021,and the design of 3D-CRT and dIMRT plans on average density projection(AIP)images,related dosimetric parameters[D_(2%),D_(50%),D_(98%),D_(mean),V_(95%),V_(100%),V_(110%),homogeneity index(HI),conformal index(CI)and gradient measurement(GM)]in the planning target area(PTV)of the two plans,and dosimetric parameters(V_(X)、D_(mean)、D_(max))related to organs at risk(whole lung,contralateral lung,heart,esophagus and spinal cord),machine hop count(MU)and exposure doses in normal tissues(NT)outside the target area were compared.Results In terms of dosimetric parameters related to PTV,the D_(2%),D_(98%),D_(mean),V100,V_(110%),HI and CI in dIMRT plan were better than those of 3D-CRT plan,and the differences were statistically significant(P<0.05).In terms of dosimetric parameters related to organs at risk,there were statistically significant differences in V_(5),V_(30),V_(40)and D_(mean)of whole lung,V_(5)of contralateral lung,V_(40)of heart and D_(mean)of spinal cord between the two plans(P<0.05).In addition,V_(5)for whole lung and contralateral lung,and D_(mean)for spinal cord in 3D-CRT plan was better than those of dIMRT plan.Compared with IMRT plan,MU in 3D-CRT plan decreased by 351.21 on average,and the difference was statistically significant(P<0.05).There were statistically significant differences in NT(V_(5)、V_(30)、V_(35)、V_(40)、V_(45)and V_(50))between the two plans(P<0.05).Conclusions Both 3D-CRT and dIMRT can meet the clinical needs in the radiotherapy of NSCLC.Compared with dIMRT,there are advantages in low dose control(V_(5)of whole lung,contralateral lung and NT)and execution efficiency for 3D-CRT.However,compared with 3D-CRT,there are advantages in target dose distribution,V_(30)and V_(40)of organ at risk,and V_(30)-V_(50)of NT regulation.Clinical treatment can be flexibly selected according to the specific situation.