Tikhonov regularization modified as improved method for determining electron energy spectra from percentage depth dose curves data of broad beams

Abstract

Abstract.Experiments have shown an obvious difference between the percentage dose distribution of clinical electron beams and percentage dose distribution (PDD) of monoenergetic electron beams of accelerator nominal energy in water phantom surface, because along the way, from electron's source to phantom, electron's beam collides with headshield accelerator and air. It is evident, then, that within PDD curves depends and contain information of spectrum. Despite modelling the source by Monte Carlo method is considered the "standard gold" and that magnetic spectrometer is a method of direct measurement; inverse reconstruction is becoming the better approach to obtain electron energy spectra since it is relatively simple, quick and inexpensive when compared with the other two. In the present work, a new method of inverse reconstruction based on Tikhonov regularization is presented. The objective of this study was establish a method that be able to obtain electron energy spectrum with greater accuracy than "Classical" Tikhonov.

Design and construction of a new optical depth-dose reader for electron beam energy measurement

“…J.H.W. Visbal et al have stated the existence of the gap between electron beam source and irradiated phantom, as well as the collision of electrons with air and accelerator wall as the reasons for difference between measurement and simulation results [18].…”