Impact of prolonged fraction dose-delivery time modeling intensity-modulated radiation therapy on hepatocellular carcinoma cell killing

Table 1 Radiobiological characteristics of HepG2 and Hep3b described with parameters derived from the dose-survival curves fitted with standard LQ model and incomplete repair model.

Cell	Parameters
	SF2read (%)	SF2est (%)	α (Gy-1)	β (Gy-2)	α/β (Gy)	T1/2(min)
HepG2	89	67.6	0.118	0.038	3.1	22
Hep3b	60	34.6	0.413	0.056	7.4	19

Table 2 Surviving fraction of HepG2 and Hep3B irradiated modeling fractionated EBRT, as well as modeling IMRT with a total fraction delivery time of 15, 30 or 45 min.

Dose	Survival fraction of HepG2 and Hep3b
	Modeling EBRT-03’		Modeling IMRT-15’		Modeling IMRT-30’		Modeling IMRT-45’
	HepG2	Hep3b	HepG2	Hep3b	HepG2	Hep3b	HepG2	Hep3b
0.0 Gy	1	1	1	1	1	1	1	1
1.0 Gy×1	0.87	0.48	0.88	0.48	0.88	0.48	0.91	0.48
2.0 Gy×1	0.6636	0.3559	0.6747	0.4123	0.7012	0.4389	0.7133	0.45
2.0 Gy×2	0.4669	0.0507	0.5123	0.0546	0.5181	0.055	0.5498	0.059
2.0 Gy×3	0.2578	0.055	0.2906	0.02	0.3006	0.0208	0.3236	0.023
2.0 Gy×4	0.1321	0.0027	0.17	0.0033	0.1987	0.0049	0.2137	0.0051
2.0 Gy×5	0.0547	0.0005	0.0671	0.0007	0.0851	0.0009	0.0996	0.0011

Table 3 Results of t-tests for surviving fractions between different fraction delivery time protocols.

Fraction delivery time protocols	HepG2		Hep3b
	t	P	t	P
EBRT-03’vs IMRT-15’	-3.308	0.016	-1.199	0.276
EBRT-03’vs IMRT-30’	-3.909	0.008	-1.179	0.283
EBRT-03’vs IMRT-45’	-4.814	0.003	-1.24	0.261
IMRT-15’vs IMRT-30’	-2.823	0.03	-1.133	0.301
IMRT-15' vs IMRT-45’	-5.686	0.001	-1.301	0.241
IMRT-30’vs IMRT-45’	-4.308	0.005	-1.644	0.151