Whole-body irradiation of deuterated mice by the 10B(n, alpha)7Li reaction.

Specific pathogen-free mice, 8-12 wk of age, were supplied with either acidified tap water or acidified 30 atom % 2H2O in tap water. Thirteen days later, when body water deuterium was about 20 atom %, mice were irradiated either by neutrons or by x-rays after intraperitoneal injection of boric acid. Mortality from whole-body neutron-boron radiation, unlike mortality from whole-body x-radiation, was not lowered by such deuteration. Time intervals to death of neutron-irradiated mice were compatible with the gastrointestinal syndrome. Neither species nor numbers of colonic bacteria were measurably altered by deuteration alone. Because the toxic, nonlethal range of deuterium substitution for aqueous hydrogen in mammals is approximately 1/5th to 1/3rd, these results indicate that partial deuteration of human tissues would improve neutron capture therapy of deep tumors. Neutron penetration would be enhanced and damage to normal tissues from photons would be decreased. The number of deuterium recoils due to neutron capture by hydrogen would also be decreased.