Energy deposition around swift proton and carbon ion tracks in biomaterials

Hadron therapy is a modern cancer treatment based on the interaction of proton or heavier ion beams with living tissue, whose purpose is the destruction of the malignant tumor cells producing minimal effects on the surrounding healthy tissue. To study the physical basis of the Relative Biological Effectiveness (RBE) of different projectiles, such as protons or carbon ions, we calculate the radial distribution of energy deposited by the secondary electrons generated in biomaterials by these ions at characteristic energies around the Bragg peak. This is done by means of the simulation code SEED, which follows in detail the motion and interactions of the secondary electrons as well as the subsequent electron cascade.