鼻咽癌同期加量适形放疗生物剂量评估应用探讨  

Exploration of biological effective dose application in simultaneous integrated boost conformal radiotherapy of nasopharyngeal carcinoma

作　　者：温戈[1,2] 黄晓波[1] 孙瑞[1] 何智纯[1] 张玉晶[1] 夏云飞[1] 

机构地区：[1]中山大学肿瘤防治中心放疗科.华南肿瘤学国家重点实验室.肿瘤医学协同创新中心,广东广州510060 [2]广州医科大学附属第三医院放疗科,广东广州510150

出　　处：《中华肿瘤防治杂志》2014年第9期692-697,共6页Chinese Journal of Cancer Prevention and Treatment

基　　金：国家科技部863计划(2006AA02Z4B4);广东省科技计划(2008B030301109)

摘　　要：目的:比较局部晚期鼻咽癌同期加量(simultaneous integrated boost conformal radiotherapy,SIB-CRT)与传统后期颅底加量适形放疗技术(traditional later skull base boost technique,LB-CRT)生物等效剂量(biologically effective dose,BED)的分布差异,探讨生物剂量概念对临床应用的影响。方法:选取2012-09-12-2012-12-19在中山大学肿瘤防治中心初治的10例鼻咽癌患者,在设计分段照射70Gy常规计划的基础上,每例患者均对生物加量靶区分别设计SIB-CRT及LB-CRT 2种计划,用剂量体积直方图比较2种技术在靶区及危及器官中的物理剂量学差异,并采用L-Q模型将其转换成BED进行比较。结果:物理剂量方面,2种照射技术的计划靶体积(planning target volume,PTV)中,PTV2和PTV1的剂量分布差异无统计学意义;但SIB-CRT中PTV-G的95%处方剂量所包含靶体积百分数(V95%)为99.3%,优于LB-CRT的98.6%,P=0.005;SIB-CRT中PTV-B的V95%为97.1%,明显优于LB-CRT的48.3%,P=0.001;SIB-CRT在PTV-B的最小剂量(Dmin)为(70.2±2.1)Gy,优于LB-CRT的(68.5±3.3)Gy,提高2.48%,P=0.010;SIB-CRT在PTV-B的最大剂量(Dmax)为(77.0±1.8)Gy,优于LB-CRT的(75.6±1.1)Gy,提高1.85%,P=0.016;SIB-CRT在PTV-B的平均剂量(Dmean)为(74.2±0.8)Gy,优于LB-CRT的(72.5±1.3)Gy,提高2.34%,P=0.015。SIB-CRT较LB-CRT同侧颞颌关节Dmean减少了4.8%,50%体积所受最大剂量(D50)减少了5.1%,P值均为0.001;对侧则相应减少了5.9%和6.0%,P值均为0.007。生物学剂量方面,SIB-CRT物理处方剂量较LB-CRT低约1Gy,但两者在PTV-B的Dmin、Dmax及Dmean的BED差异增大,SIB-CRT的Dmin为87.9Gy,优于LB-CRT的85.2Gy,提高3.17%,P=0.010;SIB-CRT的Dmax为98.6Gy,优于LB-CRT的94.4Gy,提高4.45%,P=0.001;SIB-CRT的Dmean为93.8Gy,优于LB-CRT的89.8Gy,提高4.45%,P=0.001。校准后物理剂量(adjusted physical dose,APD)与BED较一致,分别提高3.08%、4.23%及4.60%。SIB-CRT中PTV-G的105%与95%等剂量曲线间物理剂量差异为10.5%,BED差异增大,达22.1%,而APD差异为13.7%,反映生物特性�OBJECTIVE：To investigate the difference of the biological effective dose between simultaneous integrated boost conformal radiotherapy （SIB-CRT） technique and traditional later skull base boost technique （LB-CRT） in locally advanced nasopharyngeal carcinoma. The influence of applying the biological dose concept on the clinical application was discussed. METHODS：Ten patients with NPC were enrolled. Based on the design of conventional plan with segmented irradiation 70 Gy,SIB-CRT and LB-CRT were designed for each patient, respectively. The physical dosimetric characteristic differences of target volume such as biological boosting target volume （BBTV） and organs at risk （OARs） were compared by using the dose volume histogram （DVH） and converted it into biologically effective dose （BED） by using the L-Q model for compared. RESULTS：In the planning target volume （PTV） of physical dosimetry,there was no significant difference in dose distribution of PTV2 and PTV1 between two techniques. However, the V95% of PTV-G was 99.30% in SIB-CRT, better than that in LB-CRT（98.6 %, P = 0. 005）. The V95% of PTV-B was 97.1% in SIB-CRT, significantly better than that in LB-CRT（48.3%,P=0. 001）. The Dmean of PTV B was （70.2±2. 1） Gy in SIB-CRT,better than that in LB-CRT （68.5＋3.3） Gy,increased by 2.48% （P=0. 010） ;The Dmax of PTV-B was （77.0±1.8） Gy in SIB-CRT,better than that in LB-CRT （75.6±1. 1） Gy,increased By 1.85% （P=0. 016） ;The D of PTV-B was （74.2±0.8） Gy in SIB-CRT,better than that in LB-CRT.（72. 5±1. 3） Gy,increased by 2.34%0 （P=0. 015）. Compared with the LB-CRT, the D and the D50 （the maximum dose that 50% target volume suffered） of the ipsilateral and contralateral temporomandibular joint in SIB-CRT were decreased by 4.8% ,5.1% （P=0. 001） and by 5.9% ,6.0% （P=0. 007） ,respectively. In biological dosimetry, the physical prescription was lower about 1 Gy in the SIB-CRT than that in the LB-CRT, but differences of BED in the Dmi, , D

关 键 词：鼻咽癌 放射疗法 生物有效剂量 L—Q模型 三维治疗计划系统 

分 类 号：R739.63[医药卫生—肿瘤]