鼻咽癌同期加量适形放疗生物剂量评估应用探讨

发布时间：2018-07-09 23:10

  本文选题：鼻咽癌/放射疗法 + 生物有效剂量　； 参考：《中华肿瘤防治杂志》2014年09期

【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%,反映生物特性的差异不如BED。结论:SIB-CRT技术更加适形和精确,且不明显增加甚至可减少部分危及器官的照射。应用BED对不同分割剂量及次数的放疗方案之间生物效应进行量化评估是可行的。
[Abstract]:Objective: to compare the distribution of (simultaneous integrated boost conformal radiotherapyne (SIB-CRT) in locally advanced nasopharyngeal carcinoma (NPC) and the bioequivalent dose (biologically effective doseBed) of (traditional later skull base boost technique LB-CRT in late stage, and to explore the effect of biological dose concept on clinical application. Methods: ten patients with nasopharyngeal carcinoma (NPC) who were initially treated in Cancer Center of Sun Yat-sen University were selected from 2012-09-12-12-19. On the basis of designing a routine plan of 70Gy irradiation, each patient designed SIB-CRT and LB-CRT respectively for the target region of biological dosage. Dose volume histogram was used to compare the difference of physical dosimetry between the two techniques in target area and endangered organs, and the L-Q model was used to convert them to BED for comparison. Results: there was no significant difference in the dose distribution between PTV2 and PTV1 in the planned target volume (planning target volume) of the two irradiation techniques in terms of physical dose. 浣哠IB-CRT涓璓TV-G鐨，

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