上海交通大学学报（医学版）

上海交通大学学报（医学版）

• 论著（临床研究） • 上一篇    下一篇

局部复发鼻咽癌容积弧形调强与适形调强的剂量学对比研究

吴府容1,2，谭 兵2，邱 大2，王 颖2   

  1. 1.广西医科大学研究生院， 南宁 530021； 2.重庆市肿瘤医院放疗科， 重庆 400030
  • 出版日期:2014-03-28 发布日期:2014-04-02
  • 通讯作者: 王 颖, 电子信箱: wy_cqszlyy@126.com。
  • 作者简介:吴府容（1987—）， 女， 住院医师， 硕士; 电子信箱: wfr10551664@126.com。

Volumetric modulated arc therapy for recurrent nasopharyngeal carcinoma: a dosimetric comparison with intensity-modulated radiation therapy

WU Fu-rong1,2, TAN Bing2, QIU Da2, WANG Ying2   

  1. 1.Postgraduate College, Guangxi Medical University, Nanning 530021, China; 2.Department of Radiotherapy, Chongqing Cancer Hospital, Chongqing 400030, China
  • Online:2014-03-28 Published:2014-04-02

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摘要：

目的 探讨在局部复发鼻咽癌治疗中容积弧形调强放疗（VMAT）与适形调强放疗（IMRT）的剂量学特点。方法 选择30例确诊的局部复发鼻咽癌患者纳入本研究。所有患者均采用同步加量技术给予处方剂量，计划大体肿瘤靶区（PGTV）：2.26 Gy/F×30 F，计划临床病灶区（PCTV）：2 Gy/F×30 F，每例患者采用相同的剂量学限制条件，分别进行双弧容积弧形调强计划与适形调强计划设计。通过其剂量学分析评估：①靶区覆盖，均匀性及适形性。②危及器官（OAR）剂量分布。③机器跳数。结果 VMAT总体的计划临床靶区平均剂量、2％靶体积受到的剂量（D2）和98％靶体积受到的剂量（D98）高于 IMRT（P<0.05）；计划临床靶区适形性指数（CI）高于IMRT（P<0.05）；均匀性指数（HI）低于IMRT（P<0.05）。VMAT右侧颞叶的D1低于IMRT（P<0.05）；VMAT脑干的 Dmax、D1高于 IMRT(P<0.05)。VMAT左侧颞颌关节的Dmax、左侧颞叶的Dmax高于IMRT（P<0.05）；脊髓Dmax、视神经Dmax、晶体Dmax和腮腺D50等OAR的剂量学指标两者比较差异无统计学意义（P>0.05）。VMAT 比 IMRT的总机器跳数平均减少了33.2%（P<0.05）。结论 对于复发鼻咽癌患者，VMAT的计划临床靶区平均剂量、适形性和均匀性优于IMRT，可以缩短机器跳数。但在正常组织保护方面，VMAT的优势不是特别明显。

关键词: 复发鼻咽癌, 容积弧形调强放疗, 适形调强放疗, 剂量学

Abstract:

Objective To explore the dosimetric characteristics of volumetric modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) during the treatment of recurrent nasopharyngeal carcinoma (rNPC). Methods Thirty patients with rNPC were selected. The target areas received two dose levels using simultaneous integrated boosts (SIB) technique, i.e. PGTV 2.26Gy/F and PCTV 2Gy/F in 30 fractions. VMAT and IMRT treatment plans were designed with the same dosimetric constraints for each patient. Dosimetric comparisons between VMAT and IMRT plans were analyzed to evaluate ①target coverage, and homogeneity and conformity of PTV, ②sparing of OARs, and ③monitor units (MUs). Results The average dose of planning clinical target, dose received by 2% (D2), and 98% (D98) of the planning clinical target volume of VMAT were higher than those of IMRT (P<0.05). The target conformity index (CI) of VMAT was higher than that of IMRT (P<0.05) and the heterogeneity index (HI) of VMAT was lower than that of IMRT (P<0.05). The right temporal lobe D1 of VMAT was lower than that of IMRT (P<0.05), while brainstem Dmax and D1 of VMAT were higher than those of IMRT (P<0.05). The right temporal lobe D1 of VMAT was lower than that of IMRT (P<0.05), while brainstem Dmax and D1 of VMAT were higher than those of IMRT (P<0.05). The left temporomandibular joint Dmax and left temporal lobe Dmax of VMAT were higher than those of IMRT (P<0.05). The differences of spinal cord Dmax, optic nerve Dmax, crystal Dmax, and parotid gland D50 between VMAT and IMRT were not statistically significant (P>0.05). Compared to IMRT, the total MU of VMAT reduced by an average of 33.2% (P<0.05). Conclusion The results indicate that VMAT provides a better average dose of planning clinical target, conformity, and homogeneity, and fewer MUs than IMRT for recurrent nasopharyngeal carcinoma patients. But for normal tissue sparing, VMAT is similar to IMRT.

Key words: recurrent nasopharyngeal carcinoma, volumetric modulated arc therapy, intensity-modulated radiation therapy, dosimetry