Table 2.
Distributions of CTDIvol and DLP for adult CT examinations
| Examinations | n | Mean | CV (%) | 25th percentile | AD (Median) |
DRL (75th percentile) |
IQR | AD/DRL |
| Head without contrast agent | ||||||||
| CTDIvol (mGy) | 702 | 74.9 | 38.6 | 59.1 | 70.0 | 85.5 | 26.4 | 0.82 |
| DLP (mGy cm) | 706 | 1153.5 | 59.3 | 867.9 | 1097.0 | 1359.8 | 491.9 | 0.81 |
| Head (non-helical) without contrast agent | ||||||||
| CTDIvol (mGy) | 339 | 81.0 | 39.2 | 62.8 | 72.9 | 90.0 | 27.2 | 0.81 |
| DLP (mGy cm) | 341 | 1010.9 | 68.7 | 800.0 | 1001.7 | 1214.0 | 414.0 | 0.83 |
| Head (helical) without contrast agent | ||||||||
| CTDIvol (mGy) | 363 | 69.2 | 35.6 | 56.0 | 66.2 | 80.0 | 24.0 | 0.83 |
| DLP (mGy cm) | 365 | 1286.6 | 50.3 | 934.0 | 1235.0 | 1500.0 | 566.0 | 0.82 |
| Head CT angiography with contrast agent | ||||||||
| CTDIvol (mGy) | 301 | 92.8 | 155.7 | 35.0 | 52.3 | 73.5 | 38.5 | 0.71 |
| DLP (mGy cm) | 303 | 1027.0 | 72.1 | 584.4 | 858.0 | 1223.8 | 639.4 | 0.70 |
| Chest without contrast agent | ||||||||
| CTDIvol (mGy) | 452 | 12.0 | 76.5 | 7.7 | 10.0 | 14.3 | 6.6 | 0.70 |
| DLP (mGy cm) | 454 | 432.2 | 44.3 | 300.0 | 400.0 | 543.4 | 243.4 | 0.74 |
| Chest with contrast agent (tumour) | ||||||||
| CTDIvol (mGy) | 320 | 14.7 | 92.6 | 8.6 | 11.3 | 16.5 | 7.9 | 0.68 |
| DLP (mGy cm) | 322 | 597.4 | 70.1 | 355.3 | 476.1 | 652.7 | 297.4 | 0.73 |
| Abdomen and pelvis without contrast agent | ||||||||
| CTDIvol (mGy) | 431 | 15.1 | 48.6 | 10.0 | 13.7 | 18.2 | 8.2 | 0.75 |
| DLP (mGy cm) | 433 | 712.5 | 50.0 | 492.0 | 650.0 | 870.9 | 378.9 | 0.75 |
| Abdomen and pelvis with contrast agent (acute abdomen) | ||||||||
| CTDIvol (mGy) | 342 | 23.8 | 133.6 | 10.3 | 15.1 | 23.0 | 12.7 | 0.66 |
| DLP (mGy cm) | 345 | 1039.4 | 76.7 | 539.1 | 827.7 | 1253.3 | 714.2 | 0.66 |
| Coronary artery without contrast agent | ||||||||
| CTDIvol (mGy) | 210 | 10.2 | 153.8 | 3.2 | 5.5 | 9.8 | 6.6 | 0.56 |
| DLP (mGy cm) | 210 | 195.3 | 174.2 | 56.0 | 85.6 | 166.6 | 110.6 | 0.51 |
| Coronary artery with contrast agent | ||||||||
| CTDIvol (mGy) | 294 | 73.1 | 103.6 | 31.3 | 54.0 | 84.8 | 53.5 | 0.64 |
| DLP (mGy cm) | 294 | 945.7 | 72.0 | 450.5 | 823.1 | 1300.0 | 849.6 | 0.63 |
| Chest and pelvis without contrast agent | ||||||||
| CTDIvol (mGy) | 419 | 14.7 | 47.8 | 10.0 | 12.8 | 16.7 | 6.7 | 0.77 |
| DLP (mGy cm) | 421 | 953.4 | 38.9 | 700.0 | 882.0 | 1133.0 | 433.0 | 0.78 |
| Liver with non-contrast and contrast agent | ||||||||
| CTDIvol (mGy) | 351 | 46.6 | 177.2 | 11.4 | 17.4 | 44.9 | 33.4 | 0.39 |
| DLP (mGy cm) | 356 | 1605.1 | 252.2 | 487.4 | 1040.7 | 1795.2 | 1307.9 | 0.58 |
| Whole-body without contrast agent (trauma) | ||||||||
| CTDIvol (mGy) | 141 | 26.1 | 110.8 | 10.9 | 14.2 | 22.4 | 11.5 | 0.63 |
| DLP (mGy cm) | 142 | 1698.6 | 173.1 | 902.3 | 1147.0 | 1596.6 | 694.3 | 0.72 |
AD, achievable dose; CTDIvol, volume CT dose index; CV, coefficient of variation; DLP, dose–length product; DRL, diagnostic reference level; IQR, interquartile range;
n indicates the number of CTDIvol or DLP values.