中华放射医学与防护杂志

朱正飞,徐志勇,陈兰飞,胡伟刚,樊旼,吴开良,夏冰,傅小龙.不同布野方法对非小细胞肺癌调强放疗计划的影响[J].中华放射医学与防护杂志,2010,30(5):576-579

不同布野方法对非小细胞肺癌调强放疗计划的影响

Impact of different beam set-up methods on quality of intensity modulated radiation therapy in non-small cell lung cancer

投稿时间：2009-12-11

DOI：

中文关键词: 非小细胞肺癌调强放射治疗剂量学设野角度射野数目

英文关键词:Non-small cell lung cancer Intensity modulated radiation therapy Dosimetry Beam angle Beam number

基金项目:

作者	单位	E-mail
朱正飞	200032 上海,复旦大学附属肿瘤医院放疗科复旦大学上海医学院肿瘤学系
徐志勇	200032 上海,复旦大学附属肿瘤医院放疗科复旦大学上海医学院肿瘤学系
陈兰飞	200032 上海,复旦大学附属肿瘤医院放疗科复旦大学上海医学院肿瘤学系
胡伟刚	200032 上海,复旦大学附属肿瘤医院放疗科复旦大学上海医学院肿瘤学系
樊旼	200032 上海,复旦大学附属肿瘤医院放疗科复旦大学上海医学院肿瘤学系
吴开良	200032 上海,复旦大学附属肿瘤医院放疗科复旦大学上海医学院肿瘤学系
夏冰	200032 上海,复旦大学附属肿瘤医院放疗科复旦大学上海医学院肿瘤学系
傅小龙	200032 上海,复旦大学附属肿瘤医院放疗科复旦大学上海医学院肿瘤学系	xlfu1964@126.com

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中文摘要:

目的探索非小细胞肺癌(NSCLC)调强放疗(IMRT)计划设计时不同的设野方法对于计划质量的影响。方法 21例Ⅰ～Ⅲ期NSCLC患者进入本研究。IMRT采用固定野静态调强技术。每例患者采用不同的设野方法共设计3套调强计划,分别为:IMRT-7,使用等角度的7个射野,射野的入射角度分别为0°、51°、102°、153°、204°、255°、306°;IMRT-5,使用等角度的5个射野,射野的入射角度为0°、72°、144°、216°、288°;IMRT-5m,使用不等角度的5个射野,设野的方法为从前述IMRT-7的7个射野中去除2个野(若患者的病灶位于左肺,则去除角度为255°、306°的两野;若病灶位于右肺则去除角度为51°、102°的两野)。IMRT计划设计时正常肺剂量限制取之于同一患者实际治疗采用的3D-CRT计划肺V₅～V₆₀。IMRT开始取处方剂量为65 Gy,根据靶区和关键器官剂量要求按每2 Gy一阶梯进行递增或递减,直至获得最佳计划。结果比较正常肺受量时发现,在V₅～V₂₅之间IMRT-5m的值较另两套计划均明显降低;V₃₀～V₄₀间3套计划相互间无明显差异;V₄₅～V₆₀间以IMRT-5计划最差;肺的平均剂量IMRT-5m最低。食管和脊髓的受量,靶区的适形性指数,以及治疗过程机器的总跳数3套计划间差异不明显。心脏V₄₀以IMRT-5m计划的值最低。两两比较时,IMRT-5较IMRT-7明显增加了靶区的异质性指数值,而其他比较无明显差异。相比于3D-CRT,IMRT-7、IMRT-5和IMRT-5m分别可提高靶区剂量(5.1±4.6)Gy、(3.1±5.3)Gy和(5.5±4.8)Gy。结论对于NSCLC的IMRT计划设计,射野方向是重要因素,调整好设野的方向可以减少照射野数目保证甚至提高IMRT计划的质量。

英文摘要:

Objective To investigate whether the change of beam set-up methods will influence the dosimetric quality of intensity modulated radiation therapy (IMRT) for non-small cell lung cancer (NSCLC). Methods Twenty-one stage Ⅰ-Ⅲ NSCLC patients were selected for this study. The technique of step and shoot was used and three different beam set-up methods were chosen for IMRT planning, including IMRT-7 with nine equal-spaced beams angled 0°, 51°, 102°, 153°, 204°, 255°and 306°; IMRT-5 with five equal-spaced beams angled 0°, 72°, 144°, 216°and 288°; and IMRT-5m which was created from IMRT-7 but excluded 2 fields (51°and 102° were omitted if there was lesion in the right lung, while 255°and 306° were excluded if there was lesion in the left lung). The dose constrains of normal lungs for IMRT were set according to V₅-V₆₀ of normal lungs obtained from the same patient’s actually treated 3D-CRT dose volume histogram. The prescription dose for IMRT started from 65 Gy, and then escalated or decreased step by step by 2 Gy once a time until the best plan was obtained. Results For normal lung dose, IMRT-5m had lower V₅-V₂₅ than the other two groups; but there was no significant difference in V₃₀-V₄₀.IMRT-5 was the worst for V₄₅-V₆₀; and mean lung dose was lowest in IMRT-5m. Dose parameters of esophagus and spinal cord, target conformity index, and total monitor units were all similar among difference plans. IMRT-5m had lowest heart V₄₀ compared to the other two groups. For target heterogeneity index, IMRT-5 was higher than IMRT-7, but there were no significant differences among IMRT-5m,IMRT-5 and IMRT-7. Compared to 3D-CRT, the prescription dose could be increased by (5.1 ±4.6) Gy for IMRT-7, (3.1±5.3) Gy for IMRT-5, and (5.5±4.8)Gy for IMRT-5m. ConclusionFewer beams and modified beam angles could result in similar, even better plan quality.

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