Mutagenic effect of low energy neutrons on human chromosome 11

Purpose: The shape of the dose–effect curve for neutrons, i.e. the question as to whether the curve is linear or supralinear in the low‐dose region, is still not clear. Therefore, the mutagenic effect of very low doses of low‐energy neutrons was determined.Materials and methods: Human–hamster hybrid AL cells contain human chromosome 11, which expresses the membrane protein CD59. This membrane protein can be detected immunologically and quantified by flow cytometry. The AL cells were irradiated with neutrons of 0.565, 2.5 or 14.8 MeV and the results were compared with those after 200 kVp X‐rays. Before irradiation, cells spontaneously mutated in the CD59 gene were removed by magnetic cell sorting (MACS).Results: The relative biological effectiveness (RBE) for CD59 mutation induction was 19.8 (±2.7) for 0.565 MeV, 10.2 (±1.9) for 2.5 MeV, and 10.2 (±1.6) for 14.8 MeV neutrons. Linear mutation responses were obtained with all radiations except for 14.8 MeV neutrons where a supralinear curve may be a better f...