Table 1.
Dose restriction on organs at risk.
| OARs | Priority level | Desirable dose | MAC |
|---|---|---|---|
| Brain stem | 1 | D0.03ccPRV ≤ 54 Gy | ≤60 Gy |
| Optic chiasma | 1 | D0.03ccPRV ≤ 54 Gy | ≤60 Gy |
| Optic nerves | 1 | D0.03ccPRV ≤ 54 Gy | ≤60 Gy |
| Spinal cord | 1 | D0.03ccPRV ≤ 45 Gy | ≤50 Gy |
| Temporal lobes | 2 | T1-2: D0.03ccPRV ≤ 65 Gy | / |
| T3-4: D0.03ccPRV ≤ 70 Gy | ≤72 Gy | ||
| Lenses | 3 | D0.03cc ≤ 6 Gy | D0.03cc ≤ 15 Gy |
| Eyes | 3 | Dmean ≤ 35 Gy | D0.03cc ≤ 50 Gy |
| Pituitary gland | 3 | D0.03cc ≤ 60 Gy | D0.03cc ≤ 65 Gy |
| Parotid glands | 4 | Dmean ≤ 26 Gy | V30<50% (at least one side) |
| Mandible | 4 | D2 ≤ 70 Gy | ≤75 Gy |
| TMJs | 4 | D2 ≤ 70 Gy | ≤75 Gy |
| Inner ears | 4 | Dmean ≤ 45 Gy | ≤55 Gy |
| Oral cavity | 4 | Dmean ≤ 40 Gy | ≤50 Gy |
| Thyroid gland | 4 | V50 ≤ 60% | V60 ≤ 10cm3 |
OARs, organs at risk; MAC, maximum acceptance criteria; TMJs, temporal-mandibular joints, PRV, planning target volume; D0.03cc, an approximate maximum dose for the organs at risk; Dmean, the mean dose of the organs at risk; D50, dose received by 50% of the volume; D2, dose received by 2% of the volume; V50, the volume of which received 50 Gy; V60, the volume of which received 60 Gy.