title: [Consideration of large in homogeneous regions of the computation of electron dose distributions].
abstract: A simple method, suggested by Laughlin and Pohlit for calculation of dose distribution in electron beams which is considering the nonhomogeneous structure of the body, has been examined with regard to its accuracy within the energy range up to 42 MeV. Thereby, the dose distributions calculated and measured over nonhomogeneous thorax phantoms were compared. The method is based on the dose in homogeneous muscular tissue for a depth of area-weight identical to that in nonhomogeneous tissue with corrections being made according to the law of squared distances. Thus, only the loss of electron energy but not the scattering is considered. Smaller nonhomogeneous zones are completely neglected, larger ones treated as regions of equal density. The present study of the region of the lung and previous papers concerning bones [13] and cavities [11] show that the method, apart from near surface cavities, yields a satisfying exactness of the calculated dose distributions. If larger inhomogeneities - especially of the lung - are regarded, their mean tissue density, their shape, size and location ought to be known as exactly as possible.
mesh_terms: D004583:Electrons; D006801:Humans; D008168:Lung; D008433:Mathematics; D009132:Muscles; D011879:Radiotherapy Dosage; D013909:Thorax
vernacular_title: Berücksichtigung grosser Inhomogenitätsbereiche bei der Berechnung von Elektronendosisverteilungen