The R.B.E. of Different Energy Neutrons as Measured by the Haematopoietic Spleen-colony Technique

Summary

The spleen-colony technique has been used for determining the relative biological effectiveness (r.b.e.) for several energies of neutron radiation. Donor mice were exposed to fission and accelerator-generated neutrons at a variety of doses and energies. Immediately after exposure, donor bone-marrow was removed from the hind legs, and standard amounts were injected intravenously into lethally X-irradiated recipients. After 7 days the recipients spleens were evaluated for surface colonies. Dose–response curves were obtained for each type of radiation and the D₀ was determined. The neutron r.b.e. values from the D₀ compared with 250 kVp X-rays were: reactor 1·58, ²⁵²Cf 1·59, and accelerator varied from 2·85 at 1·0 Mev to 0·85 at 13·4 MeV.