Table 1.
CTC protocol for a 16-row MDCT scanner
| Manufacturer | Siemens Somatom Sensation16 | |
|---|---|---|
| Position | Prone | Supine |
| Collimation (mm) | 16×1.5 | 16×0.75 |
| Table feed/rotation (mm) | 30 | 18 |
| Slice thickness (mm) | 5+2 | 5+1 |
| Reconstruction interval (mm) | 4+1 | 4+1 |
| Rotation time (s) | 0.5 | 0.5 |
| kVp | 120 | 120 |
| mAs | 50 | 100 |
| Scan direction | Cranio-caudal | Cranio-caudal |
| Contrast material | Unenhanced | 150 ml |
| Flow rate (ml/s) | — | 4 |
| Scan delay (s) | — | 50 |
| Matrix size | 512×512 | 512×512 |
In case of suspected tumor in the recto-sigmoid colon, the first scan (unenhanced) is performed in the supine position, and the contrast-enhanced scan in the prone position for better distension of recto-sigmoid colon.