. Author manuscript; available in PMC: 2022 Jun 2.

Published in final edited form as: Radiother Oncol. 2017 Nov 8;125(2):234–240. doi: 10.1016/j.radonc.2017.09.035

Table 3.

Dose-response parameters for the logistic model.

Group	Volume	Slope (γ₅₀)	EQD2
Group	Volume	Slope (γ₅₀)	TD₂₀ (Gy)	TD₅₀ (Gy)
Both hippocampi	100%	0.42	10.9	59.3
	50%	0.53	22.1	62.9
	0	0.55	37.0	101.4
	1 cc	0.57	33.3	85.5
Left hippocampus	100%	0.49	14.0	47.3
	50%	0.44	17.1	78.4
	0	0.45	23.7	101.7
	0.5 cc	0.42	18.4	100.4
Right hippocampus	100%	0.52	19.3	57.2
	50%	0.51	24.1	75.2
	0	0.48	28.8	105.1
	0.5 cc	0.49	25.9	90.0

TD_X: tolerated dose (EQD2) resulting in X% risk of HVLT-R DR decline in 6 months.

The slope parameter (γ₅₀) of the dose–response curve in the logistic normal-tissue complication probability (NTCP) model without volume effect is calculated at TD₅₀.