自动勾画软件ABAS在鼻咽癌自适应放疗中的应用

摘要

目的:评估ABAS自动勾画软件勾画的危及器官准确度和效率,以此来评估它在鼻咽癌患者自适应放疗中的适用程度.方法:随机抽取15例在我院治疗的鼻咽癌患者.CT1为患者的计划CT,CT2为三分之二疗程重薪扫描的CT图像,CT3为患者放疗结束后扫描的CT图像.在ABAS软件中CT1图像设为模板,在CT2和CT3上自动勾画出所需的危及器官,并将自动勾画结果和手工勾画的结果进行对比分析.利用形状相似性指数(Dice similarity coefficient,DSC)和自动勾画时间评价软件自动勾画的精准性和效率性.结果:ABAS软件自动勾画的体积较大的危及器官的DSC指数均大于0.9,在CT1和CT2组中DSC指数的最高为脊髓(0.96±0.01),最低为晶体(0.43±0.19),在CT1和CT3组中DSC指数最高为下颌骨(0.93±0.45),最低为晶体(0.49 ±0.17).同时用ABAS自动勾画危及器官所需平均时间为十分钟左右.结论:在鼻咽癌自适应放疗过程中,自动勾画软件勾画的危器官可以达到很好的准确度同时又明显的节省时间.这样就可以快速评价危及器官受量,使得鼻咽癌自适应放疗成为可能.%Objective:To study the application of atlas-based autosegmentation (ABAS)software in the adaptive radiation therapy of nasopharyngeal carcinoma(NPC),and to evaluate the accuracy of organs at risk auto-contoured by the ABAS software.Methods:Fifteen NPC patients were selected randomly.There were three groups of CT images.CT1 was the planning CT.CT2 was the rescanned CT images when patients finished 2/3 radiation therapy treatment.Wheu patients finished the treatment,a new CT image date set was taken (CT3).The CT1 was set to be the model in ABAS software and the OARs were contoured automatically on CT2 and CT3 image sets.The Dice similarity coefficient(DSC)and contouring time were used to evaluate ability of ABAS software.Results:The average of DSC large volume OAR was ＞ 0.9.The spinal cord had the highest DSC (0.96 ± 0.01) while the lowest was lens(0.43 ± 0.19) between the first and second images.Similarly mandibular bone had the highest DSC (0.93 ±0.45)while lens had the lowest DSC(0.49 ± 0.17)between the first and third images.It took about ten minutes to accomplish the autocontouring with ABAS software.Conclusion:ABAS software had the excellent ability to contour OARs automatically during NPC adaptive radiation therapy.It had well accuracy and saved a lot of time.ABAS software could help to evaluate the dose to OAR during NPC radiation therapy quickly,and it was useful to NPC adaptive radiation therapy.