Table 2. Dosimetric comparison of critical organ doses between proton therapy (PT) and intensity-modulated radiotherapy (IMRT).
| Critical organ | Mean dose (range), Gy | Dosimetric improvement | P value | |
|---|---|---|---|---|
| PT | IMRT | |||
| Heart | 15.3 (7.5–25.9) | 22.8 (15–31.4) | 36.5% (6–55%) | 0.0016 |
| Esophagus | 12.3 (1.6–27.4) | 27.6 (14.3–36.5) | 60.0% (23–91%) | 0.0004 |
| Breast | 5.4 (1.7–9.7) | 10.1 (1.1–19.1) | 10% (−54–81%) | 0.2731 |
| Lung | 10.9 (4.9–16.9) | 16.0 (11.5–21.6) | 33.5% (6–57%) | 0.0070 |
| Lung V20 | 20.3% (10.1–30.9%) | 27.9% (20.9–42.6%) | 27.7% (0–53%) | 0.0287 |
PT, proton therapy; IMRT, intensity-modulated radiotherapy.