Table 1.
Optimal energy of maximum contrast‐noise‐ratio (CNR) in monoenergetic images. The P‐value indicates the maximum P‐value of CNR between the optimal energy and other energies. The maximum contrast and CNRs of monoenergetic images averaged among patients are shown in absolute value. The CNR of composed, mixed and VNC images are also listed as percentage of maximum CNR of monoenergetic images
| OAR | Energy of maximum CNR (keV) | P‐value | Maximum contrast | Maximum CNR | % of max CNR in monoenergetic image | ||
|---|---|---|---|---|---|---|---|
| Mean ± SD | Mean ± SD | Mean ± SD | Composed | Mixed | VNC | ||
| Brain stem | 78.5 ± 5.3 | 0.018 | 20.6 ± 12.5 | 2.5 ± 1.6 | 71.0% | 78.0% | 43.0% |
| Mandible | 78.0 ± 4.2 | 0.001 | 1266.9 ± 336.3 | 156.1 ± 70.3 | 73.9% | 81.7% | 36.4% |
| Parotid | 78.5 ± 5.7 | 0.023 | 27.8 ± 11.6 | 4.7 ± 1.7 | 71.5% | 72.8% | 45.7% |
| Spinal cord | 78.5 ± 5.3 | 0.037 | 20.3 ± 10.5 | 2.9 ± 0.9 | 75.7% | 77.2% | 41.4% |
| Average | 78.5 ± 5.0 | 73.0% | 77.4% | 41.6% | |||