Table 2.
Comparison of dosimetric parameters for irradiation of bladder cancer and normal organs at risk (OARs) by using different treatment techniques.
| IMRT | HT | 2DRT | P value | ||
|---|---|---|---|---|---|
| PTV | UI | 1.09 ± 0.01 | 1.01 ± 0.01 | 1.10 ± 0.03 | IMRT vs. HT: p = 0.001 2DRT vs. IMRT: p = 0.19 2DRT vs. HT: p = 0.002 |
| CI | 1.22 ± 0.06 | 1.20 ± 0.03 | 3.17 ± 1.01 | IMRT vs. HT: p = 0.19 2DRT vs. IMRT: p < 0.001 2DRT vs. HT: p < 0.001 |
|
| Right Femoral head (V30) | mean (%) |
35.0 ± 0.2 | 6.0 ± 0.1 | 73.7 ± 19.7 | IMRT vs. HT: p = 0.001 2DRT vs. IMRT: p < 0.001 2DRT vs. HT: p < 0.001 |
| Left Femoral head (V30) | mean (%) |
26.5 ± 0.3 | 6.1 ± 0.1 | 71.1 ± 22.9 | IMRT vs. HT: p = 0.03 2DRT vs. IMRT: p < 0.001 2DRT vs. HT: p < 0.001 |
| Rectum | mean (Gy) | 34.3 ± 9.1 | 25.4 ± 5.9 | 50.4 ± 8.1 | IMRT vs. HT: p = 0.019 2DRT vs. IMRT: p < 0.001 2DRT vs. HT: p < 0.001 |
| V55Gy < 50% (%) |
4.7 ± 9.6 | 1.4 ± 2.8 | 46.1 ± 36.8 | IMRT vs. HT: p = 0.28 2DRT vs. IMRT: p = 0.001 2DRT vs. HT: p < 0.001 |
|
| Intestine | mean (Gy) | 29.2 ± 9.3 | 20.7 ± 6.6 | 40.2 ± 13.2 | IMRT vs. HT: p = 0.034 2DRT vs. IMRT: p = 0.034 2DRT vs. HT: p < 0.001 |
| 250 c.c. < 45 Gy (c.c.) |
25.9 ± 30.1 | 10.8 ± 11.9 | 192.6 ± 132.6 | IMRT vs. HT: p = 0.16 2DRT vs. IMRT: p = 0.001 2DRT vs. HT: p < 0.001 |
The Vx is the percentage of femoral head volume that receives ≥ X Gy in the total femoral head volume.
Abbreviations:
2DRT: Conventional whole pelvic radiation therapy; CI: Conformal index; IMRT = intensity-modulated radiation therapy; HT = helical tomotherapy; UI: Uniformity index.