Experimental study of stereotactic body radiotherapy dosimetry for primary hepatic carcinoma based on LQ model
Objective To investigate whether the dosimetric effects of stereotactic body radiotherapy(SBRT)in hepatic carcinoma conform to the linear-quadratic(LQ)model.Methods Human hepatic carcinoma cell lines HepG2 and Hep3B cultured in vitro were selected and subjected to biological equivalent dose(BED)irradiation(6,8,10,12,14 Gy).The fractionation regimens included single-fraction irradiation(simulated SBRT)and 3-or 5-fraction irradiation(simulated IMRT).The surviving fraction after irradiation reflected the damage effects of different fractionation regimens;the effects of different fractionation regimens on cell proliferation were analyzed through survival curves;and cell scratch experiment after irradiation was used to observe the cell invasive and migration abilities after exposure to different fractionation regimens.Results Significant separation effect was observed in the in vitro validation of the LQ model in SBRT for hepatic carcinoma.For HepG2 cells and Hep3B cells,when BED<12 Gy(α/β=10 Gy),fractionation regimens did not show significant differences in terms of damage effects,proliferative ability,and invasive ability,indicating SBRT conformed to the LQ model;when BED≥12 Gy,single-fraction had more obvious damage effects as compared with multiple-fraction,indicating that the damage effect in SBRT was more significant than that in IMRT.Conclusion The LQ model applies to SBRT for hepatic carcinoma in a certain dose range,beyond which the damage effect is higher than the predicted results of the LQ model.
hepatic carcinomalinear-quadratic modelfractionation regimenstereotactic body radiotherapy
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