Table 2. Phantom experiments for identifying the ideal mAs for low dose protocol.
| Kilovoltage (kV) | Effective mAs (mA) | CTDIvol (mGy) | Effective dose (mSv) | Noise | Dose reduction (%) |
|---|---|---|---|---|---|
| 120 | 90 (135.0) | 7.01 | 4.42 | 7.5 | 0.0 |
| 100 | 135 (202.5) | 6.75 | 4.28 | 7.4 | 3.1 |
| 100 | 130 (195.0) | 6.50 | 4.12 | 7.5 | 6.7 |
| 100 | 125 (187.5) | 6.24 | 3.96 | 7.5 | 10.3 |
| 100 | 120 (180.0) | 5.99 | 3.80 | 7.9 | 13.9 |
| 100 | 115 (172.5) | 5.74 | 3.64 | 8.0 | 17.5 |
| 100 | 100 (150.0) | 5.00 | 3.17 | 8.5 | 28.2 |
| 100 | 90 (135.0) | 4.49 | 2.85 | 9.3 | 35.3 |
| 100 | 80 (120.0) | 3.99 | 2.54 | 9.8 | 42.5 |
| 100 | 70 (105.0) | 3.50 | 2.22 | 10.7 | 49.7 |
CTDIvol, volume CT dose index.