Table 2.
Averaged dosimetric values for PTV and conformal indexes
| HT Mean ± SD |
SW Mean ± SD |
RA Mean ± SD |
Protons Mean ± SD |
Pairs with statistically significant differences (P = . < 05)/Technique with best result (mean values) | |
|---|---|---|---|---|---|
| PTV | |||||
| PTV coverage (%) | 98.2 ± 1.4 | 98.6 ± 0.8 | 98.3 ± 0.8 | 99.6 ± 0.2 | Pr > HT, Pr > SW, Pr > RA / Pr > SW > RA > HT |
| D2 % (%) | 103.3 ± 0.5 | 102.5 ± 0.4 | 102.4 ± 0.3 | 102.5 ± 0.4 | RA > HT, SW > HT, Pr > HT / RA > SW = Pr > HT |
| D98 % (%) | 95.3 ± 1.9 | 95.5 ± 0.6 | 95.3 ± 0.6 | 96.7 ± 0.4 | Pr > HT, Pr > SW, Pr > RA / Pr > SW > RA > HT |
| Homogeneity index, HI | 0.08 ± 0.02 | 0.07 ± 0.01 | 0.07 ± 0.01 | 0.06 ± 0.01 | Pr > HT, Pr > SW, Pr > RA / Pr > SW = RA > HT |
| Conformation number, CN | 0.81 ± 0.04 | 0.89 ± 0.02 | 0.91 ± 0.03 | 0.88 ± 0.02 | SW > HT, RA > HT, RA > SW, RA > Pr, Pr > HT / RA > SW > Pr > HT |
| ICRU Conformity index, CIICRU | 1.20 ± 0.1 | 1.09 ± 0.03 | 1.07 ± 0.04 | 1.13 ± 0.03 | SW > HT, SW > Pr, RA > HT, RA > Pr, Pr > HT / RA > SW > Pr > HT |
| Coverage index, CΔ | 0.22 ± 0.1 | 0.11 ± 0.03 | 0.08 ± 0.03 | 0.13 ± 0.03 | RA > HT, RA > SW, RA > Pr, SW > HT / RA > SW > Pr > HT |
| Coverage index COV, CΔCOV | 0.98 ± 0.01 | 0.99 ± 0.01 | 0.98 ± 0.01 | 1.00 ± 0.0 | Pr > HT, Pr > SW, Pr > RA / Pr > SW > RA = HT |
Abbreviations: HT helical tomotherapy; SW Sliding Window; RA Rapid Arc; Pr Protons; SD standard deviation; > dosimetric superiority