Radiation dose indices, noise, and CNR of temporal bone helical scans with fixed effective mAs and different pitches
| Pitch | CTDIvol (mGy) | Noise | CNR | ||||
|---|---|---|---|---|---|---|---|
| Axial | Coronal | ||||||
| Brain Stem | Sphenoid | Brain Stem | Air | Axial | Coronal | ||
| 0.19 | 20.2 | 152.4 | 46.4 | 72.3 | 47.5 | 8.7 | 15.5 |
| 0.31 | 20.4 | 134.0 | 47.2 | 68.8 | 41.6 | 9.7 | 16.8 |
| 0.44 | 20.3 | 106.7 | 49.5 | 72.1 | 48.7 | 11.7 | 15.5 |
| 0.685 | 20.1 | 109.3 | 45.3 | 72.7 | 51.3 | 11.5 | 17.2 |
| 0.935 | 20.1 | 123.3 | 48.7 | 76.3 | 60.5 | 10.3 | 13.6 |
| 1.19 | 21.4 | 131.2 | 48.5 | 70.5 | 50.7 | 9.8 | 15.5 |
| 1.315 | 21.8 | 117.5 | 51.7 | 73.7 | 65.3 | 10.6 | 13.5 |