Chromosome aberrations in human fibroblasts induced by monoenergetic neutrons. I. Relative biological effectiveness

Journal Article · Sat Jun 01 04:00:00 EDT 1996 · Radiation Research

DOI:https://doi.org/10.2307/3579364· OSTI ID:387370

Pandita, T K; Geard, C R ^[1]

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1. Columbia Univ., New York, NY (United States)

The relative biological effectiveness (RBE) of neutrons for many biological end points varies with neutron energy. To test the hypothesis that the RBE of neutrons varies with respect to their energy for chromosome aberrations in a cell system that does not face interphase death, we studied the yield of chromosome aberrations induced by monoenergetic neutrons in normal human fibroblasts at the first mitosis postirradiation. Monoenergetic neutrons at 0.22, 0.34, 0.43, 1, 5.9 and 13.6 MeV were generated at the Accelerator Facility of the Center for Radiological Research, Columbia University, and were used to irradiate plateau-phase fibroblasts at low absorbed doses from 0.3 to 1.2 Gy at a low dose rate. The reference low-LET, low-dose-rate radiation was {sup 137}Cs {gamma} rays (0.66 MeV). A linear dose response (Y = {alpha}D) for chromosome aberrations was obtained for all monoenergetic neutrons and for the {gamma} rays. The yield of chromosome aberrations per unit dose was high at low neutron energies (0.22, 0.34 and 0.43 MeV) with a gradual decline with the increase in neutron energy. Maximum RBE (RBE{sub M}) values varied for the different types of chromosome aberrations. The highest RBE (24.3) for 0.22 and 0.43 MeV neutrons was observed for intrachromosomal deletions, a category of chromosomal change common in solid tumors. Even for the 13.6 MeV neutrons the RBE{sub M} (11.1) exceeded 10. These results show that the RBE of neutrons varies with neutron energy and that RBEs are dissimilar between different types of asymmetric chromosome aberrations and suggest that the radiation weighting factors applicable to low-energy neutrons need firmer delineation. This latter may best be attained with neutrons of well-defined energies. 36 refs., 6 figs., 5 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 387370
• Journal Information: Radiation Research, Journal Name: Radiation Research Journal Issue: 6 Vol. 145; ISSN 0033-7587; ISSN RAREAE
• Country of Publication: United States
• Language: English

Related Subjects

56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BIOLOGICAL RADIATION EFFECTS
CESIUM 137
CHROMOSOMAL ABERRATIONS
FIBROBLASTS
LET
MITOSIS
NEUTRONS
RBE