Talk:Electron therapy

Rising dose?

Why would the dose rise first with increasing depth? I know that particles are slowing down over time and so when they reach a certain lower speed the effects can get different (like they can be captured), but as far as I know photons can only interact with matter once, they can't lose only part of their energy, and thus the dose must be decreasing exponentially if the same matter is present at every point. So the shown graphic needs an explanation why the dose is first getting higher with increasing depth. Also, I'm missing a citation for the data that was used to create the graph.--Pflanze2 (talk) 09:23, 1 November 2014 (UTC)

It is due to lack of electronic equilibrium at the surface. Nearly all the dose deposited following a photon interaction actually comes from the electrons liberated in Compton and PhotoElectric interactions. These have a range of 0.5-3cm depending on energy, and are predominantly forward oriented. So the dose does not reach a maximum until the range of these electrons is reached. — Preceding unsigned comment added by 194.176.105.133 (talk) 15:38, 11 December 2014 (UTC)