Table 2.

Critical organ constraints

		Constraints
Liver metastases	Normal liver	V21 < 33%
		V15 < 50%
	stomach	V21 < 5 cm3
	Spinal cord	maximal dose < 22 Gy
	Kidney	V 15 < 33%
Lung metastases	normal lung (= volume of right + left lung – PTV)	V5 < 50%
		V10 < 30%
	One lung	V 20 < 20%
	Heart	V24 < 15 cm3
		Dmax < 30 Gy
	trachea and principal bronchi	V 15 < 4 cm3
		V 20 < 1 cm3
		Dmax < 30 Gy
	esophagus	V 21 < 5 cm3
		Dmax < 25 Gy