Figure 1
From: Proton radiotherapy for pediatric tumors: review of first clinical results
Simplistic example of depth-dose profiles (PDD) for a 10 cm seated tumor (gray area) within the patient (black circle) using four-fields photon beams and two-fields proton beams (blue and red lines, respectively). In the bottom right, final PDD due to the sum of individual photon (blue) and proton (red) beams: protons allow a dose reduction of tissues located before and behind the tumor in comparison to photons with the same target coverage.