Dose 2016

• H only reflects attenuation coefficient of tissue to diagnostic x-ray energies • Electron density insufficient for protons Need RSP and Z

Proton interactions: • Electronic

– ionization – excitation

• Nuclear

– Multiple Coulomb scattering, small θ – Elastic nuclear collision, large θ – Nonelastic nuclear interaction

B Schaffner. Phys. Med. Biol. 43 (1998)

Matsufuji (2003) looked at extending stoiciometric for multiple scattering And found up to 10% errors but minimum effect on patient distributions