Clonogenic Growth of Melanoma B-16 Cells after Irradiation at BARS-6 Pulse Reactor
Purpose: Study of variable dose rate gamma-neutron irradiation influence in mice melanoma B-16 cells (suspension and monolayer) clonogenic growth. Material and methods: The culture of murine melanoma B-16 cells was irradiated at the BARS-6 pulse (~ 65 мs, dose rate of 10 <sup>4</sup>-10 <sup>5</sup> Gy/s) and in continuous mode with dose rate of ~ 10 <sup>-4</sup>-10 <sup>-3</sup> Gy/s. The gamma installation "LUCH" ( <sup>60</sup>Co) with dose rate of 1.7x10 <sup>-2</sup> Gy/s is a source of reference radiation. Irradiation regime efficacy was compared via relative biological effectiveness (RBE) ratios calculated from dose-effect curves. The growth of irradiated cells colonies was followed up for 11 days. Results: RBE ratios of gamma-neutron irradiation in continuous mode were 3.4 and 3.6 for cells in suspension and monolayer and 3.6 and 3.1 for pulse mode. It was found that cells irradiated in suspension condition have a longer delay in cell division after irradiation and slower colony growth rate. Conclusion: RBE ratios of BARS-6 irradiation on murine melanoma B-16 cells clonogenic growth with high dose rate pulse mode and in continuous mode did not show significant mutual differences. It was shown that cells in suspension condition have a slightly higher radiosensitivity than cells in monolayer condition.