THEORETICAL STUDY ON SURVIVING FRACTION FOR V79 CELLS IRRADIATED BY 40KeV/μm DEUTERON ION: A CASE OF CLUSTERING DAMAGES

A model based on the concept of clustering damages has been proposed to relate dose absorbed by cell population to the initial biological damages. The key input is the size distribution of ionization clusters formed by ionizing radiation in 3nm diameter sphere (nucleotide) and 10nm diameter sphere (nucleosome) calculated by detailed Monte Carlo simulation code. The clustering damage based model also includes particular bio-geometrical information of cell at different cell cycle point. Some experimental and empirical data were used to transform the ionization cluster size distribution into lethal and potentially lethal cross sections (cell-1Gy-1), which are just the input of Lethal and Potentially Lethal (LPL) model. The model enables us to calculate the average number of fatal lesions at long time after irradiation and then surviving probability at different dose level and dose rate for specific kind of radiation characterized by cluster size distribution. To test the model, the surviving curves of V79 cell line at G1 phase and S phase irradiated by 40keV/μm deuteron ion were calculated and acceptable results were obtained.