放射治疗计划系统在鼻咽癌面颈联合野与颈前切线野衔接中的应用  

The Application of Radiotherapy Treatment Planning System in the Junction of the Facio-upper Neck Field and the Tangential Low Neck-supraclavicular Field for Nasopharyngeal Carcinoma

作　　者：倪千喜[1] 张琳[1] 

机构地区：[1]湖南省肿瘤医院放疗科,湖南长沙410013

出　　处：《中国医学物理学杂志》2010年第6期2218-2223,2243,共7页Chinese Journal of Medical Physics

摘　　要：目的:利用放射治疗计划系统(TPS)对鼻咽癌面颈联合野与颈前切线野进行射野衔接,观察射野衔接处的剂量分布。方法:选择一例鼻咽癌患者,通过CT模拟定位,利用TPS进行鼻咽癌面颈联合野与颈前切线野间的射野衔接。使得射野衔接处剂量均匀,同时模拟计算鼻咽癌常规定位时相邻射野重叠或留空1 mm,2 mm,3 mm,4 mm,5 mm时衔接处的剂量。均给予第一阶段处方剂量36 Gy/18次,分析射野衔接处感兴趣区域(ROI)的剂量分布情况。结果:相邻射野重叠1 mm～5 mm,ROI接受120%处方剂量的体积≥10%,135%处方剂量的体积≥5%,Dmax为处方剂量的143%～148%。脊髓的最大剂量几乎没有影响,其变化幅度≤0.5%。脊髓的V36增加约3%;相邻射野留空1 mm～5 mm,ROI的D95从36Gy降到24.1 Gy,降幅为33%。结论:利用TPS进行鼻咽癌面颈联合野与颈前切线野的衔接,可以保证射野衔接处的剂量均匀性,避免出现严重的剂量冷点及热点,确保靶区内剂量,较好地保护部分正常组织。Objective：To use the radiotherapy treatment planning system（TPS） in the junction of the facio-upper neck field and the tangential low neck-supraclavicular field for nasopharyngeal carcinoma（NPC）,analysed the dose distribution of the junction.Methods：One NPC patient received the junction of the facio-upper neck field and the tangential low neck-supraclavicular field by the the radiotherapy treatment planning system.Obtaining the uniformity of dose in the junction,calculated the dose when the adjacent fields overlapped or blanked for 1 mm,2 mm,3 mm,4 mm,5 mm.The prescription dose of the first phase was 36 Gy/18F.The dose distribution of the regions of interest（ROI） was analysed in the junction.Results：The adjacent fields overlapped 1 mm～5 mm,the volume of over 120% prescription dose ≥10%,over 135% prescription dose ≥5%.The biggest dose was 143%～148% prescription dose.The maximum dose of the spinal cord was unchanged nearly,the amplitude of variation was less than 0.5%,the V36 of the spinal cord increased about 3%;The adjacent fields blanked 1 mm～5 mm,the D95 of ROI decreased from the prescription dose 36 Gy to 24.1 Gy,the amplitude of variation was up to 33%.Conclusions：It＇s very useful to apply the TPS in the junction of the facio-upper neck field and the tangential low neck-supraclavicular field for nasopharyngeal carcinoma（NPC）,which would make sure the dose uniformity in the junction,avoid the serious hot or cold dose regions,ensure the dose of target,protect the normal tissue.

关 键 词：鼻咽癌 面颈联合野 颈前切线野 射野衔接 剂量均匀性 

分 类 号：R739.6[医药卫生—肿瘤] R815.6[医药卫生—临床医学]