Table III.
Comparison of expected and measured HU values for scan C for both scanners (right hand columns). The expected values for scanners A to C are from patient studies. Simulated values are from Monte Carlo simulations of clinical dose distributions. The measured phantom values for scanner 1 and scanner 2 are after a subtraction of 60 HU.
| Tissue | Published data | This study | ||||
|---|---|---|---|---|---|---|
| Mean CT number scanner A 53 (120 kVp) | Mean CT number scanner B 54 (120 kVp) | Mean CT number scanner C 54 (120 kVp) | Simulated value (120 kVp 52 , not specified 55 ) | Mean scanner 1 (120 kVp) | Mean scanner 2 (120 kVp) | |
| Gray matter | 29.9 ± 3.8 | 33.2 ± 0.74 | 34.18 ± 0.97 | 40 52 | 35.8 ± 9.9 | 32.9 ± 6.7 |
| White matter | 22.7 ± 3.8 | 25.06 ± 0.6 | 26.11 ± 0.93 | 34 52 | 29.3 ± 9.5 | 27.4 ± 6.1 |
| Cerebrospinal fluid | — | — | — | 13 52 | 22 ± 10.4 | 19.5 ± 6.9 |
| Cancellous bone | — | — | 568–828 55 , 999 52 | 690 | 715 | |