Normal tissue complication probability modeling for cochlea constraints to avoid causing tinnitus after head-and-neck intensity-modulated radiation therapy

Table 2 Normal tissue complication probability fitted parameters

NTCP model	TD ₅₀, Gy (95 % CI)	γ₅₀ or m (95 % CI)	TD ₂₀, Gy (95 % CI)
Logistic	46.31 (41.46–52.50)	1.27 (1.02–1.55)	33.62 (30.15–38.27)
LKB	46.52 (41.91–53.43)	0.35 (0.30–0.42)	32.82 (29.58–37.69)

Abbreviation: CI confidence interval, NTCP normal tissue complication probability, LKB Lyman-Kutcher-Burman, TD ₅₀ the dose predicting a 50 % risk of complications, TD ₂₀ the dose predicting a 20 % risk of complications, m a unitless LKB model parameter for describing the slope of the dose–response curve, γ ₅₀ a Logistic model parameter for normalized slope of the dose–response curve
The CIs were calculated by fixing one parameter at its best-fit value and allowing the other parameter to vary

ISSN: 1748-717X