Lafond C, Jouyaux F, Bellec J, Henry O, Perdrieux M, Chajon E, Le Prisé E, de Crevoisier R, Manens J-P
Centre Eugène-Marquis, rue de La-Bataille-Flandres-Dunkerque, CS 44229, 35042 Rennes cedex, France.
Cancer Radiother. 2010 Oct;14(6-7):539-49. doi: 10.1016/j.canrad.2010.06.012. Epub 2010 Aug 21.
Intensity-modulated radiation therapy (IMRT) is essential to have a dose distribution matching with the planning target volume (PTV) in case of concave-shape target. Today IMRT delivery techniques with linear accelerator can be divided into two classes: techniques with fixed gantry, called "step and shoot" (S&S) and "sliding window" (SW), and rotational techniques, called intensity modulated arc therapy (IMAT) and volumetric modulated arc therapy (VMAT). We discuss about constraints for IMRT implementation from dosimetric planning to treatment delivery. We compare S&S and VMAT performances concerning dose distribution quality, efficiency and delivery time. We describe quality controls that must be implemented and the methods for analysis and follow-up performances. VMAT tends to yield similar dose distribution to MRT with fixed gantry. VMAT also decreases monitor units as well as treatment delivery time to less than 5 minutes. However, VMAT is an IMRT technique more difficult to master than S&S technique because there are more variable parameters.
在靶区呈凹形的情况下，调强放射治疗（IMRT）对于获得与计划靶区（PTV）相匹配的剂量分布至关重要。如今，使用直线加速器的IMRT照射技术可分为两类：固定机架技术，称为“步进式”（S&S）和“滑动窗口”（SW），以及旋转技术，称为调强弧形治疗（IMAT）和容积调强弧形治疗（VMAT）。我们讨论了从剂量学计划到治疗实施过程中IMRT实施的限制因素。我们比较了S&S和VMAT在剂量分布质量、效率和照射时间方面的性能。我们描述了必须实施的质量控制以及分析和跟踪性能的方法。VMAT往往能产生与固定机架的MRT相似的剂量分布。VMAT还能减少监测单位以及将治疗照射时间缩短至不到5分钟。然而，VMAT是一种比S&S技术更难掌握的IMRT技术，因为其可变参数更多。
