Organ at risk dose constraint guide
| Organ at risk | Constraint* | ||
| Dose level | Optimal | Mandatory | |
| Rectum | 17 Gy | 50% | 80% |
| 28 Gy | 20% | 60% | |
| 33 Gy | 15% | 50% | |
| 36 Gy | 5% | 30% | |
| Other bowel | V25 | 139 cm3 | 208 cm3 |
| V28 | 122 cm3 | 183 cm3 | |
| V31 | 105 cm3 | 157cm3 | |
| V33 | 84 cm3 | 126 cm3 | |
| V36 | 26 cm3 | 39 cm3 | |
| Femoral heads | 28 Gy | – | 50% |
*The constraints provided serve only as a guide with recommendation that the optimal constraints particularly for other bowel should be met for the small plan and mandatory constraints should be met for medium plan.