Tissue heterogeneity corrections for high energy electron treatment planning

As to the factors which affect the dose calculation in tissue heterogeneity for an electron beam, the energy of the beam and the anatomical information of the inhomogeneous region will be more significant than the field size of the beam or the electron density of the tissue. It will be possible to calculate the dose at a point up to 10 cm depth in the lungs for 12 to 25 Mev (up to 7 cm for 12 Mev) electron beams with an accuracy of +-5% if the electron density has an accuracy of +-15%. As the result of our study, the accuracy of the dose calculation using the AET method and the Fermi-Eyges pencil beam method proposed by Hogstrom was X-bar = 0.982+-0.424, σn/X-bar x 100 = 43.2% and X-bar = 1.01+-0.08, σn/X-bar x 100 = 7.9%, respectively. (author)