To quantify the effectiveness of deuterons and helium particles at low doses, the inactivation rate in
vitro for V79 cells has been extracted from radiobiological published data. The Physical parameters
characteristics of these charged particles such as the linear energy transfer, the restricted linear
energy transfer, the linear primary ionization and the mean free path are determined. The
relationship between the inactivation rate and the physical parameters for deuterons and heluim-3
particles has been established in this research. This approach enables in getting the distinctive
biological response in terms of varies physical quality parameters. The best statistical regression
fittings are formulated for each correlation.