biostudies-literatureUnknown201(4)Paterson LCAtomic Energy of Canada Limited's Federal Nuclear Science & Technology Work PlanThe reported relative biological effectiveness (RBE) for thermal neutrons has a large range (5-51, for cytogenetic endpoints), which can confound radiation protection decision-making. To determine whether thermal neutron spectra can influence RBE, the RBE of reactor-derived thermal neutrons of average energy 31 meV was evaluated in human peripheral blood lymphocytes using two classical DNA double-strand break endpoints: the dicentric chromosome assay (DCA) and the cytokinesis-block micronucleus assay. Dose-response curves for 41 to 408 mGy revealed a preference for linear regression. Maximum RBE (RBEM) values of 6.7 ± 0.9 and 4.4 ± 0.7 were calculated for the DCA and the micronucleus assay, respectively. These 31 meV RBEM values were significantly lower than our prior results for 64 meV thRadiation protection dosimetry297-313https://www.ebi.ac.uk/biostudies/studies/S-EPMC11926985biostudies-literatureRelative biological effectiveness of 31 meV thermal neutrons in peripheral blood lymphocytes.PMC11926985Boyer CPaterson LCAli FNaseri MCostello CPerez Loureiro DYbarra NStuart MFestarini ARogge RKildea JRichardson RBfalseRelative biological effectiveness of 31 meV thermal neutrons in peripheral blood lymphocytes.The reported relative biological effectiveness (RBE) for thermal neutrons has a large range (5-51, for cytogenetic endpoints), which can confound radiation protection decision-making. To determine whether thermal neutron spectra can influence RBE, the RBE of reactor-derived thermal neutrons of average energy 31 meV was evaluated in human peripheral blood lymphocytes using two classical DNA double-strand break endpoints: the dicentric chromosome assay (DCA) and the cytokinesis-block micronucleus assay. Dose-response curves for 41 to 408 mGy revealed a preference for linear regression. Maximum RBE (RBEM) values of 6.7 ± 0.9 and 4.4 ± 0.7 were calculated for the DCA and the micronucleus assay, respectively. These 31 meV RBEM values were significantly lower than our prior results for 64 meV th2025-01-01T00:00:00Z2025 Mar2025-04-05T12:38:43.397Z2025-04-05T12:38:43.397ZS-EPMC119269854006282510.1093/rpd/ncae231