头颈部肿瘤自适应放疗中不同治疗方案的剂量学比较  

Dosimetric comparison of different treatment plans in adaptive radiotherapy for head and neck cancer

作　　者：汪志[1,2] 张练[2] 石成玉 徐榭[2] 陈志[2] 龙腾飞[1] 罗薇薇[1] 唐虹[1] 王凡[1] 

机构地区：[1]安徽医科大学第一附属医院肿瘤放疗科,安徽合肥230022 [2]中国科学技术大学放射医学物理中心,安徽合肥230025 [3]圣文森医疗中心肿瘤放疗科,美国康涅狄格州桥港市06606

出　　处：《中国医学物理学杂志》2016年第10期982-986,共5页Chinese Journal of Medical Physics

基　　金：国家自然科学基金(11575180;11375181)

摘　　要：目的:研究基于形变配准头颈部肿瘤自适应放疗计划剂量学优势。方法:选取8例头颈部肿瘤患者行自适应放疗,每周扫描CT重新勾画靶区和危及器官并设计新的计划执行1周,直至分次治疗结束。以初始计划CT1为参考分别进行形变配准,每周实际受照剂量在CT1上累积得到自适应方案总受照剂量。同时计算初始计划剂量和虚拟常规放疗实际受照剂量作为对比。结果:8例患者自适应方案PTV D95剂量平均值较初始计划低45 c Gy,与初始计划剂量基本一致,剂量均匀性指数(HI)和适形指数(CI)分别提高0.002和0.031。左右腮腺Dmean分别降低24.37和127.50 c Gy,脑干和脊髓D_(max)平均降低189.87和111.37 c Gy。虚拟常规放疗PTV D95剂量较初始计划低334.87 c Gy,未达到初始计划剂量,HI和CI分别下降0.073和0.069,左右腮腺Dmean分别高出153.63和170.50 c Gy,脊髓D_(max)平均高出113.37 c Gy。结论:常规放疗方案患者靶区实际受照剂量低于计划剂量,部分危及器官受到超量照射。自适应放疗方案可使靶区受照剂量与初始计划剂量保持一致,同时降低危及器官剂量,具有显著的剂量学优势。Objective To evaluate the dosimetric advantage of adaptive radiotherapy plan based on deformable image registration for head and neck cancer. Methods Eight patients with head and neck cancer were randomly selected and weekly scanned by CT. The target volume and organs at risk （OAR） were delineated weekly for re-planning. The new plans were performed for a week until the fractional treatment ended. The original planning CT （CT1） was set as the reference CT for deformable image registration. The weekly delivery doses of CT1 were accumulated to obtain the total delivery dose of adaptive radiotherapy plan. The doses of original plan and the delivery dose of virtual conventional plan were also calculated and compared. Results The mean dose of planning target volume （PTV） 995 in adaptive radiotherapy plan for 8 patients was 45 cGy lower than that in the original plans, basically consistent with the dose of original plans. Compared with original planned dose, the homogeneity index （HI） and conformal index （CI） of adaptive plan respectively increased by 0.002 and 0.031, and the mean dose （D^o~） of left and right parotid gland, and the maximum dose （Dm^x） of brain stem and spinal cord respectively decreased by 24.37, 127.50, 189.87 and 111.37 cGy. The PTV Dg~ in virtual conventional plan was 334.87 cGy lower than that in original plan, without reaching the dose of original plan. Compared with original planned dose, HI and CI of virtual conventional plan respectively decreased by 0.073 and 0.069, while the Dmax of left and right parotid gland and the Dmax of spinal cord respectively increased by 153.63, 170.50, 113.37 cGy. Conclusion The delivery dose of target volume in conventional plan is lower than that in original plan, with over-radiated OAR dose. Adaptive radiotherapy can gain consistent target dose with original plan, and reduce the OAR dose, with significant dosimetric advantages.

关 键 词：头颈部肿瘤 形变配准 自适应放疗 虚拟计划 剂量学 

分 类 号：R730.55[医药卫生—肿瘤] R739.6[医药卫生—临床医学]