A comparative study of the biological effectiveness of 14-MeV neutron pulse and continuous radiation using mouse melanoma B-16 cells

The study was carried out using compact neutron generators with a sealed tube operating in pulsed (neutron generator ING-031) and continuous (NG-14) modes. Neutron radiation was formed due to reaction T(d,n)4He. The average flow of 14-MeV neutrons was 6.6x109 ns-1 for ING-031 and 1.2-1.6x1010 n s-1 for NG-14. Duration of an impulse was ∼1 ms and pulse frequency of 50 Hz. The gamma rays of 60?? source with an average energy of 1.25 MeV were standard radiation. Biological efficacy was estimated using the clonogenic activity of mice melanoma B-16 cells. Comparison of biological effects of neutron irradiation in pulse and continuous modes showed no significant difference between them. RBE values of pulse (ING-031) and continuous (NG-14) neutron radiation were equal-in the range of 2.4-2.6. According to the clonogenic activity of melanoma B-16 cells no dose rate effect was observed within the studied range of neutrons doses and dose rates. 1 - The values of RBE ratios received in the present study correspond to available data relevant to 14-MeV neutrons and melanoma B-16 cells. 2 - According to the clonogenic activity of melanoma B-16 cells no DRE within studied ranges of neutron doses and dose rates was observed. 3 - Portable generators providing continuous neutron radiation due to its more stable performance have a higher practical potential than the sources operating in the pulse mode. (authors)