Table 2.
Comparison of the three categories of dual-energy CT
| Dual-Source system | Single-Source System | Dual-Layer Detector system | ||
|---|---|---|---|---|
| X-ray tube | Two | One | One | |
| Detector | Two | One | Two | |
| Tube potential switch | - | During each scan (0.2 ms) | Between each scan (<1 s) | - |
| Voltage | 140 kV (tube A) | 140 kV and 80 kV | 135 kV and 80 kV | 80/120/140 kV |
| 80 kV (tube B) | ||||
| Temporal resolution | 66 ms | 165 ms | 177 ms | 127 ms |
| Spatial resolution | 0.40 mm3 | 0.23 mm3 | 0.50 mm3 | 0.625 mm3 |
| Scanning time | 0.25 s | 0.35 s | 0.27 s | |
| Heart scanning time | 0.25 s | 7 s | 1-2 s | 2 s |
| Scanning mode | High-spiral acquisition | Retrospective ECG-gated spiral acquisition | ||
| Or shuttle mode | ||||
| Advantage | High temporal resolution | Exact BH correction | Better material decomposition | The two views exactly registered |
| Disadvantage | Degraded CNR | Imaging artifacts | Motion artifacts | Suboptimal material decomposition |
| Data truncation artifacts | BH artifacts | |||
| Example of representing vendor | Siemens | GE | Toshiba | Philips |
ECG, Electrocardiograph; BH, Beam hardening; CNR, Contrast to noise ratio.