TABLE 4.
Average dose parameters for the target and organ at risk with various beam numbers for low‐ or moderate‐ and high‐risk patients.
| The average dose parameters for target and OAR | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low‐risk parietns | High‐risk parietns | ||||||||||||||||||||
| Dosimetric parameters | p‐value | Dosimetric parameters | p‐value | ||||||||||||||||||
| 5 beams | 7 beams | 9 beams | 16 beams | 20 beams | 5 beams vs. 7 beams | 7 beams vs. 9 beams | 9 beams vs. 16 beams | 16 beams vs. 20 beams | 5 beams | 7 beams | 9 beams | 16 beams | 20 beams | 5 beams vs. 7 beams | 7 beams vs. 9 beams | 9 beams vs. 16 beams | 16 beams vs. 20 beams | ||||
| PTV‐Rectum‐UrethraPRV | PTV‐Rectum‐UrethraPRV | ||||||||||||||||||||
| D98% (Gy) | 35.71 | 35.90 | 35.92 | 35.92 | 35.95 | <0.01 | 0.02 | 0.53 | 0.03 | D98% (Gy) | 35.26 | 35.37 | 35.39 | 35.45 | 35.43 | <0.01 | 0.19 | <0.01 | 0.89 | ||
| Dmax (Gy) | 38.92 | 38.32 | 38.15 | 38.12 | 38.03 | <0.01 | <0.01 | 0.14 | <0.01 | Dmax (Gy) | 43.15 | 42.54 | 42.29 | 42.08 | 42.00 | <0.01 | <0.01 | <0.01 | 0.03 | ||
| PTV/rectum | PTV/rectum | ||||||||||||||||||||
| D98% (Gy) | 34.73 | 34.63 | 34.89 | 34.74 | 34.61 | 0.79 | 0.05 | 0.73 | 0.85 | D98% (Gy) | 35.21 | 34.54 | 34.65 | 34.84 | 34.66 | 1.00 | 0.53 | 0.18 | 0.96 | ||
| Rectum | Rectum | ||||||||||||||||||||
| V36Gy (cc) | 0.03 | 0.02 | 0.03 | 0.02 | 0.03 | 0.02 | 0.98 | 0.04 | 0.99 | V36Gy (%) | 0.08 | 0.05 | 0.07 | 0.06 | 0.05 | <0.01 | 0.99 | 0.01 | 0.15 | ||
| V32.6 Gy (%) | 1.21 | 1.11 | 1.08 | 1.01 | 1.04 | 0.09 | 0.23 | 0.07 | 0.76 | V32.6 Gy (%) | 0.82 | 0.53 | 0.59 | 0.53 | 0.50 | <0.01 | 0.99 | 0.01 | 0.09 | ||
| V29Gy (%) | 3.41 | 2.78 | 2.65 | 2.56 | 2.51 | <0.01 | 0.01 | 0.04 | 0.76 | V29Gy (%) | 2.47 | 1.74 | 1.71 | 1.65 | 1.55 | <0.01 | 0.49 | 0.14 | <0.01 | ||
| V25.3 Gy (%) | 6.74 | 4.85 | 4.64 | 4.53 | 4.45 | <0.01 | <0.01 | 0.05 | 0.16 | V25.3 Gy (%) | 6.26 | 4.47 | 4.05 | 4.10 | 3.93 | <0.01 | <0.01 | 0.81 | 0.05 | ||
| V21.7 Gy (%) | 12.20 | 7.55 | 7.17 | 7.12 | 6.94 | <0.01 | <0.01 | 0.26 | 0.05 | V21.7 Gy (%) | 14.24 | 10.46 | 8.78 | 9.15 | 8.93 | <0.01 | <0.01 | 0.97 | 0.19 | ||
| V18.1 Gy (%) | 22.44 | 12.20 | 11.24 | 11.69 | 11.21 | <0.01 | <0.01 | 0.98 | 0.01 | V18.1 Gy (%) | 29.91 | 24.80 | 19.53 | 20.89 | 20.55 | <0.01 | <0.01 | 0.99 | 0.27 | ||
| Bladder | Bladder | ||||||||||||||||||||
| V37Gy (cc) | 2.61 | 1.22 | 0.81 | 0.74 | 0.64 | <0.01 | <0.01 | 0.03 | 0.10 | V37Gy (%) | 6.17 | 5.01 | 4.54 | 4.65 | 4.63 | <0.01 | <0.01 | 0.93 | 0.32 | ||
| V18.1 Gy (%) | 40.81 | 36.72 | 35.73 | 36.29 | 36.35 | <0.01 | <0.01 | 0.99 | 0.67 | V18.1 Gy (%) | 40.73 | 36.80 | 33.92 | 36.61 | 36.73 | <0.01 | <0.01 | 1.00 | 0.69 | ||
| UrethraPRV | UrethraPRV | ||||||||||||||||||||
| V38Gy (cc) | 0.03 | 0.00 | 0.00 | 0.00 | 0.00 | <0.01 | 1.00 | 0.50 | 1.00 | Dmax (Gy) | 40.08 | 39.63 | 39.43 | 39.35 | 39.41 | <0.01 | <0.01 | 0.06 | 0.93 | ||
| Left femural head | Left femural head | ||||||||||||||||||||
| Dmax (Gy) | 18.74 | 17.41 | 17.21 | 16.19 | 15.54 | <0.01 | 0.36 | <0.01 | <0.01 | Dmax (Gy) | 19.44 | 15.51 | 18.24 | 14.74 | 13.50 | <0.01 | 1.00 | <0.01 | <0.01 | ||
| V14.5 Gy (%) | 5.37 | 2.43 | 2.50 | 1.26 | 1.06 | <0.01 | 0.82 | <0.01 | 0.10 | V14.5 Gy (%) | 7.05 | 0.33 | 2.49 | 0.15 | 0.00 | <0.01 | 1.00 | <0.01 | <0.01 | ||
| Right femural head | Right femural head | ||||||||||||||||||||
| Dmax (Gy) | 16.60 | 16.74 | 15.76 | 15.75 | 15.49 | 0.69 | <0.01 | 0.65 | 0.04 | Dmax (Gy) | 16.61 | 15.61 | 16.36 | 14.14 | 12.99 | <0.01 | 1.00 | <0.01 | <0.01 | ||
| V14.5 Gy (%) | 2.50 | 1.63 | 0.84 | 2.00 | 1.46 | 0.06 | <0.01 | 1.00 | 0.13 | V14.5 Gy (%) | 2.60 | 0.53 | 1.22 | 0.03 | 0.00 | <0.01 | 1.00 | <0.01 | 0.01 | ||
| CTV‐UrethraPRV | |||||||||||||||||||||
| D95% | 39.66 | 39.35 | 39.23 | 39.28 | 39.34 | <0.01 | <0.01 | 0.97 | 0.98 | ||||||||||||
Note: Parameters with significant differences are indicated in red text.
Abbreviations: CTV, clinical target volume; Dmax, maximal dose; D95%, dose administered to 95% of volume; D98%, dose administered to 98% of volume; OAR, organ at risk; PRV, planning organ at risk volume; PTV, planning target volume; PTV−Rectum−Urethra, PTV minus rectum and urethraPRV structure; PTV/rectum, common areas of PTV and rectum.