Graduate School of Biomedical Sciences, The University of Texas at Houston, 6767 Bertner, Houston, TX 77030, USA.
Phys Med Biol. 2010 May 7;55(9):2481-93. doi: 10.1088/0031-9155/55/9/004. Epub 2010 Apr 6.
Heavy charged particle beam radiotherapy for cancer is of increasing interest because it delivers a highly conformal radiation dose to the target volume. Accurate knowledge of the range of a heavy charged particle beam after it penetrates a patient's body or other materials in the beam line is very important and is usually stated in terms of the water equivalent thickness (WET). However, methods of calculating WET for heavy charged particle beams are lacking. Our objective was to test several simple analytical formulas previously developed for proton beams for their ability to calculate WET values for materials exposed to beams of protons, helium, carbon and iron ions. Experimentally measured heavy charged particle beam ranges and WET values from an iterative numerical method were compared with the WET values calculated by the analytical formulas. In most cases, the deviations were within 1 mm. We conclude that the analytical formulas originally developed for proton beams can also be used to calculate WET values for helium, carbon and iron ion beams with good accuracy.
重带电粒子束放射疗法治疗癌症的兴趣日益增加，因为它可以将高度适形的辐射剂量递送到靶体积。准确了解重带电粒子束在穿透患者身体或光束线中的其他材料后的射程非常重要，通常用水当量厚度 (WET) 来表示。然而，缺乏计算重带电粒子束 WET 的方法。我们的目的是测试先前为质子束开发的几种简单的分析公式，以确定它们计算质子、氦、碳和铁离子束照射材料的 WET 值的能力。实验测量的重带电粒子束射程和迭代数值方法得出的 WET 值与分析公式计算的 WET 值进行了比较。在大多数情况下，偏差在 1 毫米以内。我们得出结论，最初为质子束开发的分析公式也可以用于准确计算氦、碳和铁离子束的 WET 值。
