Table 4 Subgroup analysis between the linear accelerator (LA)- and CyberKnife (CK)-based systems
|  | PTV ≤ 50 cm3 (n = 7) | PTV > 50 cm3 (n = 6) | ||||
|---|---|---|---|---|---|---|
LA | CK | p-value†| LA | CK | p-value†| |
CI (ratio) | 0.91 ± 0.02 | 0.90 ± 0.03 | 0.551 | 0.82 ± 0.08 | 0.77 ± 0.05 | 0.129 |
GI (ratio) | 3.38 ± 0.46 | 2.78 ± 0.36 | 0.028 | 3.60 ± 0.66 | 3.52 ± 0.83 | 0.619 |
GM (cm) | 0.93 ± 0.15 | 0.76 ± 0.13 | 0.007 | 1.45 ± 0.07 | 1.28 ± 0.10 |  < 0.001 |
D2cm (%) | 51.0 ± 5.8 | 42.9 ± 4.1 | 0.027 | 55.5 ± 3.8 | 59.9 ± 5.4 | 0.273 |
Treatment time estimates (min) | 21.7 ± 1.8 | 120.2 ± 18.1 |  < 0.001 | 23.2 ± 0.8 | 118.2 ± 37.4 | 0.002 |
|  | Spherical PTV (n = 6) | Non-spherical PTV (n = 7) | ||||
|---|---|---|---|---|---|---|
LA | CK | p-value†| LA | CK | p-value†| |
CI (ratio) | 0.91 ± 0.01 | 0.90 ± 0.04 | 0.515 | 0.83 ± 0.07 | 0.78 ± 0.06 | 0.139 |
GI (ratio) | 3.35 ± 0.50 | 2.63 ± 0.23 | 0.029 | 3.59 ± 0.60 | 3.51 ± 0.76 | 0.531 |
GM (cm) | 0.93 ± 0.17 | 0.73 ± 0.12 | 0.006 | 1.37 ± 0.21 | 1.22 ± 0.17 | 0.001 |
D2cm (%) | 51.5 ± 6.2 | 42.9 ± 4.4 | 0.046 | 54.4 ± 4.4 | 57.5 ± 8.0 | 0.395 |