Table 1.
Dose and coverage parameters per organ at risk or target volume for VMAT and IMPT.
| Organs at risk | VMAT D2% | IMPT D2% |
|---|---|---|
| Brain | 55.1 (4.6) | 54.9 (1.3) |
| Brainstem | 51.3 (16.3) | 50.9 (17.0) |
| Optic chiasm | 31.8 (23.1) | 26.1 (27.4) |
| Cornea ipsi and bilateral | 10.1 (8.0) | 4.4 (7.1)* |
| Cornea contralateral | 4.3 (3.8) | <0.01 (<0.01)* |
| Lens ipsi and bilateral | 3.5 (2.9) | 0.96 (1.9)* |
| Lens contralateral | 1.9 (2.4) | <0.01 (<0.01)* |
| Optic nerve ipsi and bilateral | 30.8 (23.9) | 28.3 (26.6) |
| Optic nerve contralateral | 8.2 (6.8) | 0.065 (0.16)* |
| Retina ipsi and bilateral | 12.2 (10.0) | 7.5 (11.5)* |
| Retina contralateral | 4.6 (4.2) | <0.01 (<0.01)* |
| Spinal cord | 7.7 (17.0) | 10.5 (18.5) |
| Organ at risk | VMAT D40% | IMPT D40% |
| Hippocampus ipsi and bilateral | 17.6 (14.7) | 11.4 (16.0)* |
| Hippocampus contralateral | 5.6 (3.6) | 1.0 (1.7)* |
| Organs at risk/target volume | VMAT Dmean | IMPT Dmean |
| Brain | 11,2 (3.9) | 7.9 (3.0)* |
| Cerebellum anterior – CTV | 26.5 (11.2) | 15.2 (15.0)* |
| Cerebellum posterior – CTV | 17.6 (10.9) | 10.7 (12.9) |
| Cochlea ipsi and bilateral | 14.3 (9.6) | <0.01* |
| Cochlea contralateral | 6.0 (6.0) | 0.071 (0.065)* |
| Hippocampus ipsi and bilateral | 17.2 (12.8) | 11.1 (12.8)* |
| Hippocampus contralateral | 5.7 (3.9) | 1.7 (3.2)* |
| Lacrimal gland ipsi and bilateral | 8.8 (7.5) | 3.3 (5.8)* |
| Lacrimal gland contralateral | 3.7 (3.7) | <0.01 (<0.01)* |
| Supratentorial brain – CTV | 9.3 (4.3) | 6.5 (3.8)* |
| Pituitary gland | 26.5 (24.2) | 23.4 (26.4) |
| Integral dose to the body | 6.5 (2.5) | 4.5 (2.1)* |
| CTV54Gy | 57.2 (2.4) | 55.6 (2.0)* |
| GTV | 57.0 (2.5) | 55.4 (1.9)* |
| CN | VMAT D95% | IMPT D95% |
| CTV54Gy | 0,62 (0.068) | 0,57 (0.11)* |
D2%: dose to 2% of the volume reported in Gy(RBE); D40%: dose to 40% of the volume reported in Gy(RBE); Dmean: mean dose to organ at risk or target volume in Gy(RBE); D95%: dose to 95% of the volume reported in Gy(RBE) CTV54Gy: Volume of the CTV receiving 54 Gy; CN: conformity number. Numbers between parentheses are standard deviations. * numbers with asterisk are statistically significantly different (p < 0.05).