Electron dose calculation using multiple-scattering theory: second-order multiple-scattering theory.
This article is part of a series on the calculation of electron dose using multiple-scattering theory. It presents systematically the second-order multiple-scattering theory which is a generalization of the (first-order) Fermi-Eyges theory, outlining its derivation and giving explicit formulas for its defining functions. The predictions of the Fermi-Eyges theory and of the second-order theory are compared with modified Monte Carlo calculations, demonstrating the increased accuracy of the latter multiple-scattering theory. We derive and compare broad-beam angular distributions for the two theories, and note the effect of large-angle scattering upon dose profiles. Finally, we present the second-order theory in Fourier-transformed space, which is appropriate to a high-speed dose-calculation algorithm using the fast Fourier transform (FFT) technique.
Jette
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Institute of Applied Physiology and Medicine, Seattle, Washington 98122.
Bielajew
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D000465:Algorithms; D004583:Electrons; D005583:Fourier Analysis; D006283:Health Physics; D006801:Humans; D008962:Models, Theoretical; D009010:Monte Carlo Method; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy; D012542:Scattering, Radiation