Table 1.
Organs-at-risk constraints among different head and neck SBRT regimen.
| OAR Constraint | Constraint for 1 fx | Constraint for 2 fx | Constraint for 3 fx | Constraint for 4 fx | Constraint for 5 fx | Endpoint ≥ Grade 3 | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary Disease | Re-RT | Primary Disease | Re-RT | Primary Disease | Re-RT | Primary Disease | Re-RT | Primary Disease | Re-RT | Primary Disease | Re-RT | |
| Spinal cord and medulla_ PRV | Dmax 14 Gy (D0.035cc), V10 (<0.35cc) [26,27,28,29] | Dmax 9 Gy [26,30] | Dmax 17–19.3 Gy (D0.035cc), V13 (<0.35cc) [30] | Dmax 12.2 Gy [26,30] | Dmax 20.3–22.5 Gy (D0.035cc), V15.9 (<0.35 cc) [26,27,30] | Dmax 14.5 Gy [26] | Dmax 23–25.6 Gy (D0.035cc), V19.2 (<0.35 cc) [26,29] | Dmax 16.2 Gy [26,30] | Dmax 25.3–30 Gy (D0.035cc), V22 (<0.35 cc) [26,27,30] | Dmax 18 Gy [26,30] | Myelitis [29] Sahgal et al. [26]: Radiation myelopathy (1–5% risk for 1–5 fractions) | Myelitis [30] |
| Optic pathway | Dmax 10 Gy, V8 (<0.2 cc) [29] | Dmax 8 Gy [24] | Dmax 17.3 Gy, V11.7 (<0.2 cc) [29] | - | Dmax 17.4 Gy, V15.3 (<0.2 cc) [29] | Dmax Gy, V15 < 0.2 cc (Optic nerves) [24] | Dmax 21.2 Gy, V19.2 (<0.2 cc) [29] | - | Dmax 25 Gy, V23 (<0.2 cc) [29] | Dmax 10 Gy [24] | Neuritis [29] | - |
| Cochlea | Dmax 10 Gy [29], Dmax 4–12 Gy [24] | Dmax 12 Gy [24] | Dmax 13.7 Gy [29] | - | Dmax 17.4 Gy [29], Dmax 20 Gy [24] | Dmax 24 Gy [24] | Dmax 21.2 Gy [29] | - | Dmax 22 Gy [29], Dmax 25–30 Gy [24] | Dmax 20–27.5 Gy [24] | Hearing loss [29] | - |
| Brain stem (not medulla) | Dmax 15 Gy, V10 (<0.5 cc) [29] | Dmax 10–15 Gy, V10 < 1 cc [24] | Dmax 17.3, V13 Gy (<0.5 cc) [29] | - | Dmax 23.1 Gy, V15.9 (<0.5 cc) [29] | Dmax 23 Gy, V18 < 1 cc [24] | Dmax 27.2 Gy, V20.8 (<0.5 cc) [29] | - | Dmax 31 Gy, V23 (<0.5 cc) [29] | Dmax 9–15 Gy [24] | Cranial neuropathy [29] | - |
| Esophagus | Dmax 24 Gy, V20 (< 5 cc) [29], Dmax 19 Gy [24] | Dmax 10 Gy [24] | Dmax 28.3 Gy, V24.3 (<5 cc) [29] | - | Dmax 32.4 Gy, V27.9 (<5 cc) [29] | - | Dmax 35.6 Gy, V30.4 (<30.4 cc) [29] | - | Dmax 38 Gy, V32.5 (5 cc) [29], Dmax 27–35 Gy [24] | Dmax 20–25 Gy [24] | Esophagitis [29] | - |
| Brachial plexus | Dmax 16.4 Gy, V 13.6 (<3 cc) [29] | Dmax 10–16 Gy, V14.4 <3 cc [24] | Dmax 20.8 Gy, V17.8 (<3 cc) [29] | - | Dmax 26 Gy, V22 (<3 cc) [29] | Dmax 23 Gy, V22.5 <3 cc [24] | Dmax 29.6 Gy, V24.8 (24.8(3 cc) [29] | - | Dmax 32.5 Gy, V27 (3 cc) [29] | Dmax 20–32 Gy V30 < 3 cc [24] | Neuropathy [29] | - |
| Trachea | Dmax 30 Gy, V27.5 (<4 cc) [29] | - | Dmax 38 Gy, V34.5 (<4 cc) [29] | - | Dmax 43 Gy, V39<(5 cc) [29] | - | Dmax 47 Gy, V42.4(5 cc) [29] | - | Dmax 50 Gy, V45 (<5 cc) [29] | - | Stenosis [29] | - |
| Skin | Dmax 27.5 Gy, V25.5 (10 cc) [29] | - | Dmax 30.3 Gy. V28.3 (10 cc) [29] | - | Dmax 33 Gy, V31 (10 cc) [29] | - | Dmax 54 Gy, V33.6 (10 cc) [29] | - | Dmax 38.5 Gy, V36.5 (10 cc) [29] | Dmax 20 Gy [24] | Ulceration [29] | - |
| Brain | V12 Gy (10–15 cc) [31], Dmax 15–20 Gy V10 < 1 cc [24] |
Dmax 10 Gy [24] | - | - | 20 Gy (D20cc) [31], Dmax23 Gy V18 < 1 cc [24] |
- | - | - | 24 Gy (D20cc) [31], Dmax 10–25 Gy [24] | Dmax 20–23 Gy [24] | Milano et al. [31]: Symptomatic radiation necrosis (one fraction), oedema/necrosis (three and five fractions) | - |
| Carotid artery | - | Dmax 10 Gy [24] | - | - | - | - | - | - | Dmax 25–47 Gy [24] | Dmax 15–34 Gy < 50% gets PTV dose [24] | - | - |
| Parotid | - | - | - | - | - | - | - | - | - | Dmax 20–25 Gy [24] | - | - |
| Lens | - | - | - | - | - | - | - | - | - | Dmax 6 Gy [24] | - | - |
| Larynx | - | - | - | - | - | - | - | - | Dmax 20 Gy [24] | Dmax 20 Gy [24] | - | - |
Abbreviations: Dmax: Maximal dose, Fx: Fraction, OAR: Organ-at-risk, Re-RT: Re-irradiation.