Experimental research on effects of fractional irradiation with variable fraction sizes on SMMC7721 liver malignancy cells

Objective: To analyze the effects of fractional irradiation (FI) with variable fraction sizes (VFS) on SMMC7721 liver malignancy cells. Methods: Samples with the same number of SMMC7721 cells were irradiated with different FI protocols, then MTT analysis method was used to determine the cell survival probability after irradiation and comparison was made. Results: The S values of the samples irradiated with VFS protocols were all lower than those of the samples irradiated with constant fraction sizes (CFS) protocol,and the differences between part of results were of statistical significance. And for the same variety range, the effect of FI with decreasing fraction sizes was better than that of FI with increasing ones, also the differences of S values were of statistical significance. Conclusion: The result of our experiment using SMMC7721 cells is coincident with the former calculation results, indicating the VFS irradiation protocols, especially the protocol with decreasing fraction sizes, can be used in the clinic to improve the curative effect. (authors)