多发脑转移癌容积弧形调强与适形调强的剂量学对比研究  

Comparative study of dosimetry between volumetric-modulated arc therapy and intensity-modulated radiation therapy for brain metastases

作　　者：龙斌[1] 谢悦[1] 蒋勇[1] 李淑杰[1] 邱大[1] 王颖[1] 

机构地区：[1]重庆市肿瘤医院放疗科,400030

出　　处：《重庆医学》2015年第32期4535-4537,共3页Chongqing medicine

摘　　要：目的探讨多发脑转移癌在治疗中容积弧形调强放疗(VMAT)与适形调强放疗(IMRT)的剂量学特点。方法选择60例确诊的多发脑转移癌患者纳入本研究。所有患者均采用全脑放疗加肿瘤靶区后期加量技术给予处方剂量,全脑放疗30Gy/10F,病灶加量20Gy/10F至生物学剂量59Gy。每例患者采用同样的剂量学条件限制,分别进行两弧容积弧形调强计划与调强计划设计。通过其剂量学分析评估:靶区覆盖,均匀性及适形性;危及器官(OAR)剂量分布;机器跳数。结果两组治疗计划均能满足临床要求。两组眼球、晶体、视神经、视交叉、腮腺、脑干及外耳道的平均受照剂量相似,差异无统计学意义(P>0.05);VMAT组眼球、晶体、腮腺及外耳道的热点剂量小于IMRT组(P<0.05)。VMAT组有更少的机器跳数(P=0.017),照射时间更短。结论 VMAT技术可以满足临床对于多发脑转移瘤的大剂量放射治疗的计划要求;两种方案在靶区适形度、靶区均匀性无明显差别;VMAT组的眼球、晶体、腮腺及外耳道热点剂量更低;VMAT在缩短照射时间方面更具有优势。Objective To compare volumetric-modulated arc therapy（VMAT）with intensity-modulated radiation therapy（IMRT）for brain metastases with regard to the dosimetric character.Methods Sixty patients who were diagnosed with brain metastases were included in this study.The target area received two dose levels using late addition amount technique,WBRT（30Gy/10F）with following addition（20Gy/10F）to 59 Gy.For a fair comparison,VMAT and IMRT treatment plans were respectively designed for every patient with the same dosimetric constraints.Dosimetric comparisons between VMAT and IMRT plans were analyzed to evaluate：target coverage and homogeneity,conformity of PTV;sparing of OARs;monitor units（MUs）.Results Two treatment plans all reached the treatment need.When compared with IMRT,there was no significant difference in Dmean of eyeball,len,optic never,visual chiasma,parotid,brain stem,and external auditory canal of VMAT（P〈0.05）.The Dmax of eyeball,len,parotid,and external auditory canal of VMAT were lower than that in IMRT group（P〈0.05）.The VMAT group has the less MUs（P=0.017）and less treatment time.Conclusion VMAT can reach the big-dose radiotherapy need on brain metastases clinically.There are no significant diffference between VMAT and IMRT on Dmax,Dmean,CI,and HI.The Dmax of eyeball,len,parotid,and external auditory canal of VMAT were lower than that in IMRT group.The VMAT can reduce the radiotherapy time.

关 键 词：多发脑转移癌 容积弧形调强放疗 适形调强放疗 剂量学 

分 类 号：R739.41[医药卫生—肿瘤]