Parameters of different scan protocols
| Standards CT | CT Angiography | CT Perfusion | |||||
|---|---|---|---|---|---|---|---|
| Base | Cerebrum | Intracranial | Cervical | Protocol I | Protocol II | Protocol III | |
| Collimation (mm) | 20 × 1.2 | 20 × 1.2 | 64 × 0.6 | 64 × 0.6 | 20 × 1.2 | 20 × 1.2 | 20 × 1.2 |
| Table feed (mm) | 24 | 24 | 45,9 | 69,7 | 0 | 0 | 0 |
| Pitch | 1 | 1 | 1.2 | 1.8 | 0 | 0 | 0 |
| Tube current (mAseff) | 350 | 300 | 160 | 115 | 270 | 200 | 200 |
| Electrical mA | 350 | 300 | 383 | 417 | 270 | 200 | 200 |
| Potential (kV) | 120 | 120 | 100 | 120 | 80 | 80 | 120 |
| Rot. time (s) | 1 | 1 | 0.5 | 0.33 | 1 | 1 | 1 |
| Scan length (mm) | 48 | 95 | 250 | 280 | 24 | 24 | 24 |
| Scan time (s) | 6.25 | 4.58 | 40 | 40 | 40 | ||
| CTDIvol total (mGy) | 39.86 | 34.16 | 12.79 | 7.9 | 432 | 320 | 970 |
| DLP total (mGy x cm) | 203 | 348 | 386 | 277 | 1037 | 768 | 2330 |
Note:—Table feed indicates table movement per second. Pitch corresponds to the dose-relevant pitch (table feed per total collimation considering the number of detector rows acquired simultaneously). CTDI indicates computed tomography dose index; DLP, dose–length product.