Table 4.
Average Dosimetric Parameters for 4 Techniques Studied.a
| Structure | CK, Mean ± SD | RA, Mean ± SD | VMAT, Mean ± SD | ncpIMRT, Mean ± SD |
|---|---|---|---|---|
| Mean values | ||||
| Prostate, Gy | 38.3 ± 0.6b | 36.4 ± 0.4 | 36.8 ± 0.5 | 36.9 ± 0.5 |
| PTV, Gy | 37.8 ± 0.4b | 36.2 ± 0.4 | 36.5 ± 0.3 | 36.6 ± 0.4 |
| Rectum, Gy | 15.2 ± 2.6 | 13.3 ± 2.6 | 13.1 ± 2.8 | 13.8 ± 1.6 |
| Bladder wall, Gy | 13.8 ± 2.5b | 9.9 ± 2.3 | 11.3 ± 2.2 | 9.9 ± 2.2 |
| Left femur, Gy | 5.4 ± 2.1 | 5.1 ± 2.3 | 8.5 ± 2.6 | 7.1 ± 2.5 |
| Right femur, Gy | 4.7 ± 1.4 | 5.2 ± 2.2 | 7.9 ± 2.5 | 6.4 ± 2.3 |
| Penile bulb, Gy | 17.6 ± 7.1b | 5.9 ± 4.4 | 7.8 ± 5.8 | 9.8 ± 7.0 |
| Minimum constraints | ||||
| Rectum | ||||
| Dmax < 38 Gy | 38.0 ± 0.9b | 37.1 ± 0.5 | 37.1 ± 0.5 | 37.1 ± 0.4 |
| D1cm3 < 36 Gy | 35.1 ± 1.1 | 35.0 ± 0.7 | 34.5 ± 1.0 | 35.1 ± 0.8 |
| D20cm3 < 25 Gy | 16.1 ± 5.0 | 14.1 ± 4.6 | 14.1 ± 7.2 | 15.0 ± 4.1 |
| D50% < 18 Gy | 12.5 ± 2.9 | 11.0 ± 2.9 | 10.0 ± 3.5 | 11.6 ± 2.2 |
| Bladder wall | ||||
| Dmax < 38 Gy | 37.9 ± 0.8 | 37.8 ± 0.4 | 37.1 ± 0.4 | 37.6 ± 0.6 |
| D5cm3 < 37.5 Gy | 33.9 ± 2.4 | 32.3 ± 3.6 | 33.9 ± 1.7 | 31.4 ± 5.8 |
| D15cm3 < 18.3 Gy | 17.2 ± 2.0 | 14.3 ± 6.1 | 18.7 ± 8.7 | 14.8 ± 6.0 |
| Ambition constraints | ||||
| Rectum | ||||
| D4cm3 < 32 Gy | 31.1 ± 2.5 | 29.8 ± 2.5 | 29.7 ± 3.3 | 30.5 ± 2.2 |
| D20cm3 < 16 Gy | 16.1 ± 5.0 | 14.1 ± 4.6 | 14.1 ± 7.2 | 15.0 ± 4.1 |
| Bladder wall | ||||
| D2cm3 < 36.25 Gy | 36.3 ± 0.8 | 36.0 ± 0.4 | 35.7 ± 0.4 | 35.8 ± 1.3 |
| D4cm3 < 32.62 Gy | 34.9 ± 1.7 | 34.0 ± 2.1 | 34.7 ± 1.1 | 33.1 ± 4.3 |
| D10cm3 < 18.12 Gy | 25.7 ± 5.2 | 23.5 ± 7.4 | 26.5 ± 7.9 | 22.4 ± 7.4 |
Abbreviations: CK, CyberKnife; ncpIMRT, noncoplanar intensity-modulated radiation therapy; RA, RapidArc; SD, standard deviation; VMAT, volumetric-modulated arc therapy.
aN = 8 Patients.
bThe mean value differs significantly (P < .05) from the value of the other techniques.