鼻咽癌颅底破坏肿瘤靶区拆分勾画剂量学研究  

Dosimetric study on dividing delineation of gross target volume of nasopharyngeal carcinoma with skull base destruction

作　　者：黄国森[1] 谢秋英[1] 胡学锋[1] 张利文[1] 腾建建 

机构地区：[1]佛山市第一人民医院肿瘤中心放疗科,广东佛山528000

出　　处：《中国医学物理学杂志》2015年第4期537-541,567,共6页Chinese Journal of Medical Physics

摘　　要：目的:探讨鼻咽癌颅底骨质破坏调强放疗中肿瘤靶区拆分勾画的可行性,为鼻咽肿瘤和颅底骨质破坏区域给予不同处方剂量提供剂量学支持。方法:2010年7月~2011年12月将30例具有颅底骨质破坏、无远处转移的初治鼻咽癌的GTVnx拆分勾画为GTVnp和GTVbone,分别代表为鼻咽肿瘤和颅底骨质破坏区域。在每个病人的定位CT上设计3个治疗计划,第1个计划:GTVnp和GTVbone处方剂量相同,但相对较低,6800 cGy^7000 cGy;第2个计划:GTVnp和GTVbone处方剂量相同,剂量相对较高,7000 cGy^7400 cGy;第3个计划:GTVnp和GTVbone处方剂量不同,GTVnp6800 cGy^7000 cGy、GTVbone7000 cGy^7400 cGy。比较鼻咽癌颅底骨质破坏调强放疗GTV拆分勾画肿瘤靶区体积变化、肿瘤靶区及正常组织的剂量变化。结果:3个计划95%的处方剂量均能包括各自的靶区,颅底剂量分布不均匀,尤其最上两层靶区,3个计划PTVbone的Dmax与Dmin平均相差1231 cGy、1824 cGy、1731 cGy,PTVbone的Dmean分别为6910 cGy、7550.1 cGy、7541.8 cGy;鼻咽剂量分布均匀,PTVnp的Dmax与Dmin平均相差429.3 cGy、571.4 cGy、926.7 cGy;PTVnp的Dmean分别为6966 cGy、7557.6cGy、7222.7 cGy。双侧腮腺、口腔剂量与GTVnp剂量梯度相关,口腔平均剂量相差约341.5 cGy^513.4 cGy,双侧腮腺的平均剂量相差362.3 cGy^491.7 cGy。脑干、脊髓、双侧中耳、左右视神经、颞叶剂量分布无显著差异。结论:鼻咽癌颅底骨质破坏GTV拆分勾画可行,能满足鼻咽肿瘤和颅底骨质破坏区域的不同剂量要求,降低了口腔、双侧腮腺等正常组织的剂量。Objective To provide dosimetric basis for delivering different prescription dose to nasopharyngeal neoplasms and areas of skull base destruction by exploring the feasibility of dividing delineation of gross target volume （GTV） in the intensity- modulated radiotherapy （IMRT） for nasopharyngeal carcinoma （NPC） with skull base destruction. Methods From July 2010 to December 2011, 30 patients with non-metastatic NPC with skull base destruction, treated by IMRT, were analyzed. Their GTVnx were divided into GTVnp and GTVbone, respectively representing the GTV of nasopharyngeal neoplasm and areas of skull base destruction. Based on the location CT, three treatment plans were designed for each patient. In the first plan, GTVnp and GTVbone were given the same prescribed dose, 6800 cGy-7000 cGy. In the second plan, GTVnp and GTVbone were also given the same prescribed dose, 7000 cGy-7400 cGy. While the prescribed doses to GTVnp and GTVbone were different in the third plan, respectively 6800 cGy-7000 cGy, 7000 cGy-7400 cGy. The changes of target volume divided by GTV delineation and the dose to target volumes and normal tissues in the IMRT for NPC with skull base destruction were analyzed. Results The prescribed dose received by planning target volume （PTV） was more than or equal to 95% in each plan. The dose to skull base was not uniform, especially to the top two layers of target volume. The average dose differences between the maximal dose （Dmax） and minimum dose （Dmin） of PTVbooo were respectively 1231 cGy, 1824 cGy, 1731 cGy. The mean doses （Dmean） of PTVbone were respectively 6910 cGy, 7550.1 cGy, 7541.8 cGy. The dose distribution of nasopharynx was uniform and the average dose differences between Dmax and Dmin of PTVnp were 429.3 cGy, 571.4 cGy, 926.7 cGy, respectively. The Dmean of PTVnp were 6966 cGy, 7557.6 cGy, 7222.7 cGy, respectively. The doses of bilateral parotid glands and oral cavity were related to the dose gradient of GTVnp. The average dose difference of oral cavity was 341.5

关 键 词：鼻咽肿瘤 颅底破坏 调强放疗 大体肿瘤靶区 剂量学 

分 类 号：R739.63[医药卫生—肿瘤]