Calculations pertaining to the use of fast (approximately-less-than50-MeV) neutrons in cancer radiotherapy

Calculated results are presented for a variety of neutron spectra incident on a tissue‐equivalent phantom. The neutron spectra considered are those produced by 35‐ and 50‐MeV deuterons in a thick beryllium target and by 67‐MeV protons in a thick lithium target. Results are presented for the absorbed doses, LET spectra, cell‐survival probabilities, OERs, and RBEs as a function of position in the phantom. The cell‐inactivation calculations were carried out using the model of Katz et al . and parameters for T‐1 kidney cells. In the case of incident neutrons from 35‐MeV 2 H on Be, experimental and calculated absorbed‐dose data are compared as a function of position in the phantom and are shown to be in good agreement.