Open AccessWater equivalent thickness values of materials used in beams of protons, helium, carbon and iron ions
Author(s) -
Rui Zhang,
Phillip J. Taddei,
Markus M. Fitzek,
Wayne D. Newhauser
Publication year - 2010
Publication title -
physics in medicine and biology/physics in medicine and biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.312
H-Index - 191
eISSN - 1361-6560
pISSN - 0031-9155
DOI - 10.1088/0031-9155/55/9/004
Subject(s) - proton , helium , beam (structure) , charged particle , range (aeronautics) , charged particle beam , ion , materials science , particle beam , particle (ecology) , atomic physics , physics , nuclear physics , optics , oceanography , quantum mechanics , composite material , geology
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.