Dose Course 2018_Flipping book

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Conclusions

The results from this study show that contrary to the popular perception, conventional photon dose calculation using water with relative electron densities produces dose distributions that are much closer to Monte Carlo calculated dose-to-medium distributions than to dose-to-water distributions converted using mass stopping-power ratios of water to bone… … explained by the fact that the photon dose deposition depends mainly on the electron density since the predominant mode of interaction is Compton scattering for photon beams of radiotherapy interest. Thus, the dose deposition scaled based on the relative electron density is effectively dose to medium (with the corresponding electron density), as implemented in many commercial treatment planning dose algorithms in spite of their initial intentions or claimed applications.

Ma and Li, 2011

Dublin 2018