| 梁志文,王强,杨志勇,等.动态多叶光栅剂量学间隙对调强放疗的影响[J].中华放射医学与防护杂志,2014,34(2):149-151.Liang Zhiwen,Wang Qiang,Yang Zhiyong,et al.Effect of dMLC dosimetric leaf gap in IMRT and VMAT[J].Chin J Radiol Med Prot,2014,34(2):149-151 |
| 动态多叶光栅剂量学间隙对调强放疗的影响 |
| Effect of dMLC dosimetric leaf gap in IMRT and VMAT |
| 投稿时间：2013-02-28 |
| DOI：10.3760/cma.j.issn.0254-5098.2014.02.018 |
| 中文关键词: 动态多叶光栅 剂量学间隙 调强放疗 旋转容积调强 |
| 英文关键词:Dynamic multileaf collimator Dosimetric leaf gap Intensity modulated radiation therapy Volumetric modulated arc therapy |
| 基金项目: |
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| 摘要点击次数: 4067 |
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| 中文摘要: |
| 目的 研究多叶光栅剂量学间隙（DLG）对计算剂量和实际剂量的影响。方法 在Eclipse计划系统中对典型全盆腔病例分别做动态调强计划（IMRT）和容积旋转调强（VMAT）计划。计算DLG为0与0.3 cm两种极端情况下剂量学指标的差异，分析DLG变化对平均叶片间隙的影响。固定多叶光栅位置，模拟实际治疗通量，通过改变DLG的大小，分析PTV平均剂量的变化趋势。结果 DLG在0与0.3 cm下计划靶区（PTV）接受50 Gy剂量时所对应的体积（V50）、直肠V40、膀胱V40、小肠V35、左右股骨头所接受的最大剂量（Dmax）的差异分别为1.49%、0.72%、0.82%、0.68%，0.02和0.14 Gy。多叶光栅的平均叶片间隙与剂量学间隙明显相关（R2=0.996，P<0.05），且随剂量学间隙的增大而变小。实际治疗中，对典型全盆腔病例，剂量学间隙每增大0.1 cm，IMRT的PTV平均剂量降低3.95%，VMAT降低1.5%。结论 动态多叶光栅剂量学间隙会影响多叶光栅的实际位置，导致实际治疗与治疗计划的剂量学差异，剂量学间隙越大，实际剂量越低。 |
| 英文摘要: |
| Objective To explore the relationship between DLG value and planning dose distribution and actual treatment dose distribution. Methods IMRT and VMAT plans were generated in Eclipse TPS for a typical whole pelvis case, separately. For IMRT plan, MLC position and actual fluence were calculated for each DLG value with the same optimal fluence. Plans with different DLGs of 0 cm and 0.3 cm were compared by several dosimetric indexes. For exploring the PTV mean dose difference between planning dose and actual IMRT or VMAT treatment, planning dose was recalculated with fixed MLC position and different DLGs. Results Dosimetric differences of PTV V50, rectum V40, bladder V40, small bowel V35, left and right femoral head Dmax were 1.49%,0.72%,0.82%,0.68%,0.02 and 0.14 Gy respectively, the average leaf pair width of MLC segments was correlated with DLG (R2=0.996,P<0.05) and reduced with the increase of DLG. In actual treatment, 3.95% and 1.5% mean dose reduction in PTV were observed while DLG increased per 0.1 cm in the typical pelvis case, in IMRT and VMAT treatment respectively. Conclusions DLG can result in the change of MLC position and the dose difference between planning and actual treatment. |
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