Table 2. Organ dose (mGy) and effective dose (mSv) obtained in routine adult and paediatric chest CT examinations with 64-slice CT scanners.
| CT scanner |
Adult CT |
Paediatric CT |
||||||
| A | B | C | D | A | B | C | D | |
| Tube voltage (kV) | 120 | 120 | 120 | 120 | 120 | 120 | 120 | 120 |
| The method of tube current adjustment | Volume EC | Smart mA | Care Dose 4D | D-DOM | Volume EC | Smart mA | Care Dose 4D | Fixed (203 mA) |
| Effective mAsa | 186 | 134 | 266 | 112 | 37 | 28 | 116 | 100 |
| Rotation time (s rotation–1) | 0.5 | 0.4 | 0.5 | 0.5 | 0.5 | 0.4 | 0.33 | 0.5 |
| Beam width (mm) | 0.5 mm × 64 | 0.625 mm × 64 | 0.6 mm × 32 | 0.625 mm × 64 | 1.0 mm × 32 | 0.625 mm × 32 | 0.6 mm × 32 | 0.625 mm × 64 |
| Pitch factor | 0.828 | 1.375 | 1.0 | 1.015 | 1.406 | 1.375 | 1.0 | 1.015 |
| Planned scan length (mm) | 305 | 300 | 300 | 260 | 205 | 200 | 186 | 190 |
| Exposed scan length (mm) | 360 | 371 | 332 | 325 | 300 | 234 | 218 | 260 |
| Tissue or organ | Organ dose (mGy) | Organ dose (mGy) | ||||||
| Brainb | – | – | – | – | 0.3 | 0.1 | 0.5 | 0.6 |
| Lensb | – | – | – | – | 0.1 | <0.1 | 0.3 | 0.3 |
| Salivary glandsb | – | – | – | – | 4.1 | 0.5 | 1.6 | 3.8 |
| Thyroid | 19.9 | 34.8 | 26.8 | 17.2 | 8.5 | 6.4 | 17.0 | 13.5 |
| Lung | 32.4 | 16.5 | 31.2 | 12.1 | 8.8 | 4.9 | 16.1 | 12.6 |
| Breast | 23.6 | 11.3 | 18.4 | 8.2 | 8.4 | 4.1 | 12.5 | 12.0 |
| Oesophagus | 29.1 | 15.7 | 28.5 | 10.8 | 8.3 | 3.6 | 14.3 | 12.1 |
| Liver | 27.7 | 9.7 | 19.7 | 10.7 | 7.7 | 4.1 | 12.3 | 12.2 |
| Stomach | 31.0 | 11.8 | 16.6 | 12.0 | 7.7 | 1.6 | 3.4 | 6.5 |
| Colon | 3.1 | 1.7 | 1.7 | 1.1 | 0.9 | 0.3 | 0.8 | 1.1 |
| Ovaries | 0.2 | 0.1 | 0.2 | 0.1 | 0.2 | 0.1 | 0.3 | 0.4 |
| Bladder | 0.1 | 0.1 | 0.1 | <0.1 | 0.1 | <0.1 | 0.2 | 0.2 |
| Testes | 0.1 | <0.1 | 0.1 | <0.1 | 0.1 | <0.1 | 0.2 | 0.1 |
| Bone surface | 17.8 | 9.5 | 14.4 | 5.7 | 10.0 | 4.7 | 12.3 | 11.4 |
| Red bone marrow | 12.0 | 7.5 | 12.4 | 3.9 | 2.7 | 1.4 | 4.5 | 3.8 |
| Skin | 4.8 | 2.1 | 3.5 | 2.0 | 1.0 | 0.7 | 1.8 | 2.0 |
| ICRP 103 | ||||||||
| Remainder tissues | 17.6 | 10.1 | 14.1 | 7.7 | 6.3 | 3.1 | 7.5 | 7.5 |
| Effective dose (mSv) | 17.7 | 9.6 | 14.5 | 7.0 | 5.4 | 2.5 | 7.3 | 6.9 |
| ICRP 60 | ||||||||
| Remainder tissues | 15.9 | 7.6 | 11.8 | 5.8 | 5.5 | 2.3 | 5.1 | 5.5 |
| Effective dose (mSv) | 15.5 | 8.6 | 12.9 | 6.2 | 4.5 | 2.1 | 6.2 | 5.8 |
| CTDIvol (mGy) | 18.7 | 11.8 | 19.2 | 8.8 | 3.5 | 2.5 | 6.7 | 5.9 |
| DLP (mGy cm) | 672 | 436 | 635 | 286 | 104 | 59 | 146 | 153 |
CTDI, CT dose index; DLP, dose–length product; ICRP, International Commission on Radiological Protection.
a
 |
bDoses not measured for the adult phantom were assumed to be zero.