Table 3. The biological functions and additional constraints that are selected for optimization of the NPC patient plans.

Structure	Functions used
PTV70	(1)TCP Poisson LQ with D50 = 57.40 Gy, γ = 6.3, α/β = 10 Gy
	(2)Target, EUD
	(3)Max Dose
	(4)Uniformity constraint
PTV60-PTV70	(1)Target, EUD
	(2)Uniformity constraint
PTV54	(1)Target, EUD
	(2)Uniformity constraint
Brain stem	(1)NTCP Poisson LQ with D50 = 65.10 Gy, γ = 2.4, α/β = 3 Gy,
	s = 1; endpoint: necrosis/infarction
	(2)Max EUD
	(3)Max Dose
Spinal cord	(1)NTCP Poisson LQ with D50 = 68.60 Gy, γ = 1.9, α/β = 3 Gy,
	s = 4; endpoint: myelitis necrosis
	(2)Max EUD
	(3)Max Dose
Optic chiasma	(1)NTCP Poisson LQ with D50 = 65.00 Gy, γ = 2.3, α/β = 3 Gy,
	s = 1; endpoint: blindness
	(2)Max Dose
Optic nerve	(1)NTCP Poisson LQ with D50 = 65.00 Gy, γ = 2.3, α/β = 3 Gy,
	s = 1; endpoint: blindness
	(2)Max Dose
Eye retina	(1)NTCP Poisson LQ with D50 = 65.00 Gy, γ = 1.8, α/β = 3 Gy,
	s = 1; endpoint: blindness
Lens	(1)NTCP Poisson LQ with D50 = 18.00 Gy, γ = 1.2, α/β = 3 Gy,
	s = 1; endpoint: cataract
Parotid	(1)NTCP Poisson LQ with D50 = 46.00 Gy, γ = 1.8, α/β = 3 Gy,
	s = 1; endpoint: xerostomia
	(2)Max EUD
Avoid_normal	(1)Max Dose