Experimental evaluation of the impact of different headand-neck intensity-modulated radiation therapy planning techniques on doses to the skin and shallow targets
Experimental evaluation of the impact of different headand-neck intensity-modulated radiation therapy planning techniques on doses to the skin and shallow targets
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DOI：
10.1016/j.ijrobp.2007.03.004
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发表时间：
2007-10-01
影响因子：
7
通讯作者：
Tishler, Roy B.
中科院分区：
文献类型：
--
作者：
Court, Laurence E.;Tishler, Roy B.
目的：通过实验研究不同的头颈部调强放射治疗(IMRT)计划技术对皮肤和浅层靶区剂量的影响。方法与材料：使用微型MOSFET剂量计(Thomson-Nielson，渥太华，加拿大安大略省)在0、3、6、9和12 mm深度构建一个半圆柱体模。计划目标体积(PTV)从身体轮廓向后拉0、3或5 mm。制定调强放射治疗计划是为了最大限度地扩大PTV的覆盖面，采用以下策略之一：(A)目标是最大110%的热点，允许115%；(B)目标是最大105%的热点；(C)目标是最大105%的热点和50%的皮肤，以获得最大70%的处方剂量；以及(D)目标是99%的PTV体积获得90%-93%的规定剂量，最大105%的热点，并将对皮肤结构的剂量降至最低。使用直线加速器进行剂量测量。通过故意将体模移动8 mm的范围来模拟设置不确定度，并计算系统和随机不确定度范围内的递送剂量。结果：从最低到最高的皮肤剂量规划策略依次为c、d、b和a，但c有向深层组织剂量不足的趋势。根据计划策略的不同，提供剂量的差异为10%-20%。对于典型的设置不确定性，累积剂量减少到6 mm深的点是
Purpose: To investigate experimentally the impact of different head-and-neck intensity-modulated radiation therapy (IMRT) planning techniques on doses to the skin and shallow targets.Methods and Materials: A semicylindrical phantom was constructed with micro-MOSFET dosimeters (Thomson-Nielson, Ottawa, Ontario, Canada) at 0-, 3-, 6-, 9-, and 12-mm depths. The planning target volume (PTV) was pulled back 0, 3, or 5 mm from the body contour. The IMRT plans were created to maximize PTV coverage, with one of the following strategies: (a) aim for a maximum 110% hotspot, with 115% allowed; (b) aims for a maximum 105% hotspot; (c) aims for a maximum 105% hotspot and 50% of skin to get a maximum 70% of the prescribed dose; and (d) aim for 99% of the PTV volume to receive 90-93% of prescribed dose, with a maximum 105% hotspot, and with the dose to the skin structure minimized. Doses delivered using a linear accelerator were measured. Setup uncertainty was simulated by intentionally shifting the phantom in a range of 8 mm, and calculating the delivered dose for a range of systematic and random uncertainties.Results: From lowest to highest skin dose, the planning strategies were in the order of c, d, b, and a, but c showed a tendency to underdose tissues at depth. Delivered doses varied by 10-20%, depending on planning strategy. For typical setup uncertainties, cumulative dose reduction to a point 6 mm deep was