Table 2. Comparison of mean ± standard deviation dose values for target volumes and rectum .
| DVH parameter |
With RR (n = 18) |
Without RR (n = 18) |
p* | |
| PTV | ||||
| Dmean (Gy) | 70.7 ± 0.8 | 70.5 ± 0.6 | 0.424 | |
| V95% (%) | 98.09 ± 1.33 | 98.02 ± 1.42 | 0.874 | |
| Rectum | ||||
| Dmean (Gy) | 33.91 ± 2.89 | 44.21 ± 3.90 | < 0.001 | |
| Dmax (Gy) | 69.92 ± 0.95 | 70.03 ± 0.96 | 0.735 | |
| Dmin (Gy) | 2.23 ± 0.63 | 2.11 ± 0.52 | 0.538 | |
| D30% (Gy) | 41.58 ± 4.81 | 53.31 ± 4.54 | < 0.001 | |
| D50% (Gy) | 26.82 ± 10.63 | 38.88 ± 2.73 | < 0.001 | |
| V50% (%) | 43.26 ± 5.64 | 56.07 ± 3.28 | < 0.001 | |
| V60% (%) | 34.18 ± 5.25 | 46.51 ± 3.44 | < 0.001 | |
| V70% (%) | 26.96 ± 5.90 | 37.07 ± 4.95 | < 0.001 | |
| V80% (%) | 20.19 ± 4.95 | 32.23 ± 6.27 | < 0.001 | |
| V90% (%) | 14.37 ± 4.17 | 25.23 ± 4.42 | < 0.001 | |
| V95% (%) | 10.10 ± 3.64 | 19.02 ± 3.28 | < 0.001 | |
| V100% (%) | 0.88 ± 0.88 | 1.21 ± 0.88 | 0.267 |
CTV: Clinical target volume; PTV: Planning target volume; Dmean: Mean dose to the rectum (or target volume); Dmax: Maximum dose to the rectum; Dmin: Minimum dose to the rectum; Dx% dose to x% of the rectal wall volume, Vx%: Volume of the rectum (or target volume) receiving x% of prescribed dose); RR: Rectal retractor.
* P-value < 0.05 was considered statistically significant.