TABLE III.
Absolute dose discrepancies between accumulated and measured doses (values normalized by the local measured doses). Both planning 4D-CT dose accumulations (shown as column “planning 4D-CT”) and on-board 4D-CBCT dose accumulations (shown as column “on-board 4D-CBCT”) were performed and compared to the OSL measurements. The “OSL No.” indicates individual OSL measurements at locations numbered in Fig. 4. Please note that the end-inspiration phase location was fixed for different motion amplitudes. When motion amplitude increased, doses at different OSL measurement locations were affected differently.
| Absolute dose discrepancy [absolute (accumulated-measured)/measured*100] | |||||||
|---|---|---|---|---|---|---|---|
| 3D static beam | Dynamic conformal arc | IMRT | |||||
| OSL No. | Planning 4D-CT (%) | On-board 4D-CBCT (%) | Planning 4D-CT (%) | On-board 4D-CBCT (%) | Planning 4D-CT (%) | On-board 4D-CBCT (%) | |
| 3 cm on-board motion | 6 | 6.2 | 5.5 | 2.3 | 1.4 | 2.2 | 2.9 |
| 9 | 4.1 | 3.7 | 1.4 | 0.2 | 0.3 | 2.5 | |
| 11 | 3.3 | 0.6 | 3.1 | 1.2 | 9.2 | 5.5 | |
| 12 | 5.1 | 1.6 | 3.8 | 0.2 | 13.8 | 11.2 | |
| 15 | 63.6 | 2.2 | 50.6 | 6.5 | 43.4 | 2.4 | |
| 19 | 3.7 | 2.3 | 0.0 | 0.6 | 5.1 | 4.8 | |
| 21 | 3.5 | 2.0 | 0.5 | 0.9 | 4.5 | 5.1 | |
| Mean | 12.8 | 2.5 | 8.8 | 1.6 | 11.2 | 4.9 | |
| SD | 22.4 | 1.6 | 18.5 | 2.2 | 14.9 | 3.0 | |
| 4 cm on-board motion | 6 | 4.0 | 1.0 | 3.2 | 2.2 | 1.5 | 1.8 |
| 9 | 7.2 | 4.5 | 3.3 | 1.1 | 1.7 | 6.9 | |
| 11 | 48.5 | 1.5 | 36.3 | 5.8 | 68.6 | 9.6 | |
| 12 | 76.2 | 9.1 | 66.8 | 3.8 | 96.9 | 1.2 | |
| 15 | 105.1 | 4.8 | 90.5 | 4.0 | 87.9 | 7.0 | |
| 19 | 4.6 | 0.4 | 2.9 | 0.4 | 2.8 | 4.7 | |
| 21 | 6.8 | 2.7 | 3.0 | 2.0 | 2.1 | 3.1 | |
| Mean | 36.1 | 3.4 | 29.4 | 2.8 | 37.3 | 4.9 | |
| SD | 41.3 | 3.0 | 36.4 | 1.9 | 44.8 | 3.1 | |