Dosimetric comparison of non-small cell lung cancer treatment with multi fields dynamic-MLC IMRT

目的 比较治疗非小细胞肺癌(NSCLC)的5野与7、9野(以下简称F5、F7、F9)动态调强放疗(dIMRT)计划的靶区及周围各组织器官的剂量学差异,为临床应用提供参考.方法 从2012年1月至2014年10月随机抽取首钢医院肿瘤科接受动态调强放疗的非小细胞肺癌(NSCLC)患者30例利用瓦里安(Varian)计划系统(Eclipse 7.3)进行回顾分析,所有患者均做5、7、9固定野的动态调强计划,在满足靶区处方要求[95％剂量曲线包绕100％的计划靶区(PTV)]的情况下,通过剂量体积直方图(DVH)评价和比较F5、F7、F9治疗计划的PTV的最大剂量(Dmax)、最小剂量(Dmin)、和平均剂量(Dmean)以及适形指数(CI),脊髓及其他危及器官最大剂量Dmax,双肺的V5、V10、V20、V30,心脏V30,食管V5o、V60、平均剂量,并比较3种治疗计划的总机器跳数(MU).结果 F5的PTV的Dmax、Dmin、Dmean分别为(7 203±128)、(5 493±331)、(6 900±138) cGy;F7的PTV的Dmax、Dmin、Dmean分别为(7 304±96)、(5 526±296)、(6 976±130) cGy;F9的PTV的Dmax、Dmin、Dmean分别为(7 356±54)、(5 578±287)、(7 019±56) cGy.随着射野数量的增加,包绕靶区的等剂量线略有升高.靶区的适形指数CI随射野增加渐优.靶区3种调强计划中的全肺V5、V1o随射野增多略大,3种计划双肺的V20差异均无统计学意义,双肺的V30随着射野的增多略微下降,以上各数据差异均无统计学意义(均P＞0.05).食管的V5o随着射野数增大分别降低3％、5％,食管的V60分别降低6％、11％、平均剂量降低5％、10％和脊髓的Dmax降低9％、13％.F7、F9计划心脏V30较F5计划降低11％、19％.3种计划机器跳数随着射野增多而增大,F7、F9治疗时间较F5治疗时间增加15％、25％.结论 对于多野调强放射治疗NSCLC,F5、F7、F9动态调强均能满足临床靶区剂量要求,如果临床特殊要求保护患者的脊髓、食管、心脏可以选择F7或F9设计治疗计划,一般患者可选用F5设计计划,治疗时间明显缩短,提高病灶的生物效应,跳数更低,避免正常组织的不必要照射.Objective We compared the dosimetric differences between the target and surrounding tissues/organs of the 5-field and 7,9-field (Hereinafter referred to as F5,F7,F9) treatment plan in non-small cell lung cancer (NSCLC) by the dynamic intensity-modulated radiotherapy (dIMRT),to provide reference for clinical application.Methods Using Varian planning system (Eclipse 7.3),we randomly selected 30 cases of patients who received dIMRT to study,all patients were 5,7,9 fixed field dynamics intensity-modulated radiotherapy plans to meet the target prescription requirements (95％ dose curve enveloping 100％ of the PTV),by comparing dose-volume histogram DVH evaluation,and the maximum dose D the minimum dose Dmin,and the mean dose D and conformal index CI of PTV,organs at risk of spinal cord the maximum dose D lung V5,V10,V20,V30,heart V30 and esophageal V50,V60 of F5,F7 and F9 dIMRT plans,and compare the mu of the three treatment programs.Result The D Dmin and D values of F5's PTV are (7 203 ± 128) 、(5 493 ±331) 、(6 900 ± 138) cGy respectively;the D Dmin and D values of F7's PTV are (7 304 ±96) 、(5 526 ±296) 、(6 976 ± 130)cGy respectively;and the D Dmin and D values of F9's PTV are (7 356 ±54) 、(5 578 ±287) 、(7 019 ±56)cGy respectively.The data shows that while we increased the numbers of fields,the isodose line surrounding the target area would also promote slightly.The conformity index CI of target became better with the increase of radiation fields.The whole lung V5 and V10 slightly became larger with increase of fields and the V20 showed no significant difference in three models,V30 of double lungs slightly decreased with the increase of fields.The above date was statistically meaningless (P ＞ 0.05).With the increase of fields esophagus V50 were reduced by 3％ and 5％ respectively,V60 of the esophagus were reduced by 6％ and 11％,the average dose reduced by 5％ and 10％ and spinal cord Dmax decreased by 9％ and 13％.In the F7 and F9,heart V5 were lower than F5 plan by 11％,19％.The mu of them were increased with the increase of radiation fields,Treatment time of F7 and F9 plan were longer by 15％ and 25％.Conclusion Through comparing the three fixed dIMRT plans,we could draw a conclusion that the three multi-field intensity-modulated radiotherapy in non-small cell lung cancer can meet the clinical target volume dose requirements.If the treatment is required to protect the patient's spinal cord,esophagus and heart,we can choose 7or 9 fields.While other ordinary patients should be treated with 5 fields plan,to shorten the treatment time and improve the biological effectsof lesions,and lower mu of plans to avoid unnecessary irradiation of normal tissues.PubMed中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)191526-15299