| 李成强,陶城,朱健,巩贯忠,段敬豪,刘同海,尹勇,卢洁.多叶准直器叶片位置误差对鼻咽癌调强放疗剂量的影响[J].中华放射医学与防护杂志,2015,35(7):544-547 |
| 多叶准直器叶片位置误差对鼻咽癌调强放疗剂量的影响 |
| Impact of multileaf collimator position errors on simultaneous integrated boost intensity-modulated radiotherapy for nasopharyngeal carcinoma |
| 投稿时间：2014-12-02 |
| DOI：10.3760/cma.j.issn.0254-5098.2015.07.016 |
| 中文关键词: 调强放射治疗 鼻咽癌 多叶准直器 位置误差 |
| 英文关键词:Intensity modulated radiotherapy Nasopharyngeal carcinoma Multi-leaf collimator Position errors |
| 基金项目:国家自然科学基金(81301298);山东省自然科学基金(ZR2013HL044);山东省科技攻关项目(2014GSF118011) |
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| 中文摘要: |
| 目的 分析多叶准直器(MLC)叶片位置误差对鼻咽癌调强放射治疗靶区和危及器官剂量的影响。方法 选取10例已行鼻咽癌调强放疗患者计划,通过修改MLC文件,在计划文件中引入MLC叶片的位置误差,模拟调强计划执行过程中可能出现的叶片不到位情况,比较不同模拟计划与原计划的剂量学差异。结果 2 mm范围内的叶片随机误差及叶片偏移误差的剂量学影响差异无统计学意义(P>0.05),计划靶区(PGTV、PTV1及PTV2)D95%最大改变量为(-0.92±0.51)%、(1.00±0.24)%和(0.62±0.17)%,脊髓及脑干D0.1cc最大改变量为(1.90±2.80)%和(-1.78±1.42)%,左右腮腺Dmean最大改变量为(1.36±1.23)%和(-2.25±2.04)%。与原计划相比,当叶片外扩达2 mm时,PGTV、PTV1及PTV2的D95%和D5%受量显著增加(t=8.97、10.97、9.74、7.30、6.04、3.04,P<0.05);脊髓及脑干D0.1cc显著增加(t=6.16、9.22,P<0.05);左右腮腺Dmean显著增加(t=7.12、4.25,P<0.05)。结论 鼻咽癌调强放疗时,直线加速器MLC叶片在一定范围内的随机误差及叶片整体偏向一侧的位置误差对剂量分布的影响并不显著,叶片外扩及内收的位置误差对剂量分布的影响不可忽略,应加强对MLC系统位置误差的质量控制以提高放疗精度。 |
| 英文摘要: |
| Objective To investigate the impact of multileaf collimator (MLC) position errors on simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) for patients with nasopharyngeal carcinoma. Methods Totally 10 patients with locally advanced nasopharyngeal carcinoma treated with SIB-IMRT were enrolled in this study. By modifying the plan files, different MLC position errors were introduced into the clinical plans. The differences of dosimetries were compared between the original and simulated plans. Results The dosimetric impact of the random and system shift errors of MLC position was insignificant within 2 mm (P>0.05), the maximum changes in D95% of PGTV, PTV1 and PTV2 were (-0.92±0.51)%, (1.00±0.24)% and (0.62±0.17)%, the maximum changes in the D0.1cc of spinal cord and brainstem were (1.90±2.80)% and (-1.78±1.42)%, the maximum changes in the Dmean of left and right parotids were (1.36±1.23)% and (-2.25±2.04)%. For 2 mm leaf extension errors, the average changes in D95% of PGTV, PTV1 and PTV2 were increased significantly(t=8.97,10.97,9.74,7.30,6.04,3.04,P<0.05), the averaged value of the D0.1cc to spinal cord and brainstem were increased significantly (t=6.16,9.22,P<0.05), the averaged value of the mean dose to left and right parotid were increased significantly (t=7.12,4.25,P<0.05), respectively. Conclusions No significant difference was found for random and shift MLC leaf position errors up to 2 mm for nasopharyngeal carcinoma IMRT patients, respectively. There is a high sensitivity to dose distribution for MLC extension or contraction errors. The quality control of systematic MLC position errors should be paid attention in order to ensure the therapeutic accuracy. |
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