Table 2. Quantifications of the beam hardening results for the materials and scan conditions.
Measurements indicate the percentage difference between voxel grayscale values at the inner and outer portions of the phantom. Shaded fields indicate areas where beam hardening artifacts occurred.
| Phantom Material |
Test Condition |
Filtration | Phantom Thickness (mm) |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 3.048 | 3.924 | 4.801 | 5.677 | 6.553 | 7.43 | 8.306 | 9.182 | 10.058 | 10.935 | 11.811 | |||
| None | 3.4% | 6.5% | 9.3% | 8.9% | 8.8% | 10.3% | 12.2% | 12.7% | 12.3% | 13.1% | 14.5% | ||
| 0.254 mm Al | 1.2% | 4.0% | 7.5% | 7.9% | 9.1% | 11.7% | 13.7% | 13.5% | 14.3% | 15.3% | 16.1% | ||
| With Flattener | 0.508 mm Al | 1.4% | 3.8% | 7.3% | 7.0% | 7.5% | 10.4% | 11.4% | 12.7% | 13.9% | 15.1% | 16.7% | |
| 1.016 mm Al | -1.9% | 0.1% | 3.5% | 3.5% | 4.5% | 6.7% | 8.3% | 9.4% | 10.2% | 11.9% | 10.8% | ||
| 0.254 mm Al & 0.254 mm Cu | -7.1% | -7.3% | -4.6% | -5.5% | -5.0% | -3.6% | -2.1% | -1.4% | -0.8% | 1.0% | 0.7% | ||
| SB3 | |||||||||||||
| None | 5.4% | 9.0% | 12.5% | 12.9% | 14.4% | 18.5% | 21.0% | 23.2% | 25.8% | 28.1% | 30.6% | ||
| 0.254 mm Al | 5.0% | 6.8% | 10.8% | 10.2% | 11.1% | 14.5% | 17.3% | 18.8% | 20.7% | 21.9% | 24.3% | ||
| Without Flattener | 0.508 mm Al | 1.5% | 4.3% | 8.6% | 8.3% | 9.5% | 12.5% | 14.3% | 16.5% | 18.0% | 19.0% | 21.6% | |
| 1.016 mm Al | -2.3% | 0.6% | 4.6% | 4.6% | 5.7% | 8.2% | 10.0% | 11.7% | 12.8% | 14.3% | 15.3% | ||
| 0.254 mm Al & 0.254 mm Cu | -9.0% | -8.8% | -5.5% | -6.0% | -6.3% | -3.2% | -2.2% | -1.5% | -0.9% | 0.5% | 2.0% | ||
| None | -0.9% | 2.6% | 5.6% | 5.2% | 5.1% | 6.6% | 7.9% | 7.9% | 9.3% | 8.9% | 8.3% | ||
| 0.254 mm Al | -0.1% | 1.8% | 5.5% | 5.6% | 5.3% | 7.5% | 9.7% | 10.7% | 11.1% | 12.4% | 14.3% | ||
| With Flattener | 0.508 mm Al | -2.1% | 0.1% | 3.8% | 5.0% | 4.9% | 8.0% | 8.8% | 9.9% | 11.0% | 12.8% | 13.6% | |
| 1.016 mm Al | -3.5% | -2.1% | 1.1% | 1.1% | 2.4% | 3.6% | 5.4% | 6.4% | 7.5% | 9.0% | 10.5% | ||
| 0.254 mm Al & 0.254 mm Cu | -10.5% | -8.3% | -5.3% | -6.5% | -6.1% | -6.0% | -6.0% | -3.8% | -2.2% | -1.5% | -0.5% | ||
| CB2-50% | |||||||||||||
| None | 5.0% | 7.8% | 12.2% | 12.3% | 14.4% | 18.1% | 20.7% | 23.6% | 26.0% | 30.7% | 32.6% | ||
| 0.254 mm Al | 1.8% | 4.8% | 7.8% | 8.3% | 9.4% | 12.2% | 15.9% | 17.4% | 19.6% | 22.5% | 25.2% | ||
| Without Flattener | 0.508 mm Al | -0.3% | 1.9% | 5.3% | 6.0% | 6.9% | 9.9% | 12.8% | 14.8% | 16.3% | 19.1% | 20.9% | |
| 1.016 mm Al | -2.8% | -1.6% | 2.2% | 2.8% | 3.2% | 6.5% | 8.1% | 9.6% | 11.1% | 13.5% | 14.8% | ||
| 0.254 mm Al & 0.254 mm Cu | -10.1% | -7.7% | -7.2% | -6.6% | -6.7% | -5.0% | -4.5% | -3.2% | -1.8% | -0.6% | -0.8% | ||