Table 8.
Effect of obesity on CTDIvol-to-organ dose conversion coefficients.
| ⟨h⟩inside (unitless)1 |
|||||||
|---|---|---|---|---|---|---|---|
| Male |
Female |
||||||
| Scan length (cm)2 | Normal | Obese class I | Obese class II | Normal | Obese class I | Obese class III | |
| Chest-abdomen-pelvis | 71 ± 3 | 1.35 | 1.12 (−17%) | 0.89 (−34%) | 1.37 | 0.91 (−33%) | 0.64 (−54%) |
| Chest | 33 ± 3 | 1.44 | 1.16 (−19%) | 0.92 (−36%) | 1.48 | 1.00 (−33%) | 0.73 (−51%) |
| Abdomen-pelvis | 53 ± 2 | 1.27 | 1.04 (−18%) | 0.88 (−31%) | 1.26 | 0.80 (−37%) | 0.56 (−55%) |
| Abdomen | 31 ± 1 | 1.28 | 1.03 (−20%) | 0.79 (−38%) | 1.34 | 0.79 (−41%) | 0.57 (−58%) |
| Pelvis | 31 ± 1 | 1.13 | 0.93 (−18%) | 0.94 (−17%) | 1.03 | 0.75 (−28%) | 0.49 (−52%) |
| Adrenals | 15 ± 1 | 1.09 | 0.82 (−25%) | 0.65 (−40%) | 1.08 | 0.64 (−41%) | 0.44 (−59%) |
| Liver | 26 ± 2 | 1.25 | 1.00 (−20%) | 0.77 (−38%) | 1.32 | 0.76 (−42%) | 0.55 (−59%) |
| Kidneys | 19 ± 1 | 1.05 | 0.87 (−17%) | 0.66 (−37%) | 1.21 | 0.72 (−41%) | 0.45 (−63%) |
| Liver-to-kidney | 27 ± 2 | 1.23 | 1.01 (−18%) | 0.79 (−36%) | 1.30 | 0.78 (−40%) | 0.56 (−57%) |
| Kidney-to-bladder | 41 ± 1 | 1.13 | 0.89 (−21%) | 0.77 (−32%) | 1.20 | 0.74 (−38%) | 0.51 (−58%) |
1
For given phantom and examination category, ⟨h⟩inside is the CTDIvol-to-organ dose conversion coefficient averaged across fully encompassed organs (i.e., organs completely inside the scan coverage). Values in parenthesis are the percent differences between an obese phantom and the normal-weight phantom in the same gender category.
2
Scan length = image coverage + over-ranging distance.