Table 1.
Optimal VMI pairs for SPR mapping using the N&A method on the two CT scanners used in this work, in how many iterations (out of 30) the VMI pair ranked first (out of 5050 investigated pairs), the mean SPR RMSE, standard deviation, and the lowest rank of the VMI pair across 30 iterations of the optimization process. Abbreviations: SPR = stopping power ratio; CT = computed tomography; VMI = virtual monoenergetic images; N&A = Näsmark & Andersson (2021); L-S = Landry-Saito.
| Tissue type | Optimal VMI Pair [keV] | Ranked first | SPR RMSE | Lowest ranking | |
|---|---|---|---|---|---|
| Scanner 1 | Lung tissue | 113/114 | 20/30 | 5.0% ± 0.4% | 11 |
| Soft tissue | 49/52 | 10/30 | 0.5% ± 0.01% | 7 | |
| Bone | 102/103 | 30/30 | 1.1% ± 0.03% | 1 | |
| Scanner 2 | Lung tissue | 40/139 | 18/30 | 3.7% ± 1.3% | 1792 |
| Soft tissue | 44/54 | 9/30 | 0.4% ± 0.03% | 13 | |
| Bone | 134/137 | 23/30 | 0.7% ± 0.3% | 3 | |