Treatment of metastatic liver tumors using stereotactic ablative radiotherapy

Table 2 Organ at risk constraints in various prospective trials depending on their fractionation schemes[10,15,19,21,28-29,31]

Normal Liver(Liver- CTV-RFA cavities)	D30% = 6-12 Gy, D50% = 4-7 Gy	V15 Gy < 700 mL	30% < 21 Gy, 50% < 15 Gy	V15 Gy < 700 mL	V15 Gy < 700 mL	V5 Gy ≤ 700 mL, Dmean < 15 Gy	V15 Gy < 700 mL	V21 Gy < 700 mL
Stomach	Dmax ≤ 12 Gy	NA	D5 mL < 21 Gy	Dmax ≤ 30 Gy	D1 mL < 21 Gy	Dmax < 30 Gy; D5 mL < 22.5 Gy	V21 Gy < 1%	Dmax ≤ 32 Gy , D10 mL < 28 Gy
Bowel	Small bowel Dmax ≤ 35 Gy	D < 5% volume < 20 Gy	D5 mL < 21 Gy	Dmax ≤ 30 Gy	D1 mL < 21 Gy	Dmax < 30 Gy	Duodenum, small bowel V21 Gy < 1%	Duodenum: Dmax ≤ 32 Gy; D5 mL< 18 Gy Jejunum/ileum: Dmax ≤ 35 Gy, D5 mL ≤ 19.5 Gy Colon: ≤ 38 Gy, D20 mL ≤ 25 Gy
Esophagus	Dmax ≤ 14 Gy	NA	D5 mL < 21 Gy	NA	D1 mL < 21 Gy	NA	V21 Gy < 1%	Dmax ≤ 35 Gy, D5 mL < 27.5 Gy
Kidney	NA	75% volume of each kidney < 5 Gy	NA	Total kidney D35% < 15 Gy	Total kidney D35% < 15 Gy	NA	V15 Gy < 35% for both kidneys	Renal hilum/vascular trunk < 2/3 ≤ 23 Gy Renal cortex (right and left): 200 mL < 17.5 Gy (3.5 Gy/fraction)
Spinal cord	NA	Dmax < 12 Gy	NA	Dmax ≤ 18 Gy	Dmax < 18 Gy	Dmax ≤ 20 Gy	D0.1 cm3 < 18 Gy	Dmax ≤ 30 Gy, D0.25 mL < 22.5 Gy
Heart/ pericardium	NA	NA	D5 mL < 21 Gy	NA	D1 mL < 30 Gy	NA	V30 Gy < 1%	Dmax ≤ 38 Gy, D15 mL < 32 Gy
Skin	NA	NA	NA	NA	NA	NA	NA	Dmax ≤ 32 Gy, D10 mL < 30 Gy
Great vessels	NA	NA	NA	NA	NA	NA	NA	Dmax ≤ 53 Gy, D10 mL < 47 Gy
Chest wall	NA	NA	NA	NA	NA	NA	D30 cm3 < 30 Gy	NA

CTV: Clinical target volume; Dx%: Dose to x%; Dx mL/cm³: Dose to x mL/cm³; RFA: Radiofrequency ablation; NA: Not available.