Background
Methods
HU calculation applied to acquisitions with a 40kVp uncollimated cone beam
Stoichiometric method
ρZeff segmentation method
“Dose-equivalent” tissue calculation
ICRU tissues | Physical density ρ (g.cm3) | Zeff | ρZeff |
---|---|---|---|
Lung inflated | 0.26 | 7.88 | 2.05 |
Adipose | 0.95 | 6.67 | 6.34 |
Yellow marrow | 0.98 | 6.56 | 6.43 |
Average soft tissue adult female | 1.02 | 7.44 | 7.59 |
Red marrow | 1.03 | 7.44 | 7.66 |
Water | 1.00 | 7.73 | 7.73 |
Average soft tissue adult male | 1.03 | 7.60 | 7.83 |
GI tract | 1.03 | 7.71 | 7.94 |
Pancreas | 1.04 | 7.70 | 8.01 |
Breast | 1.02 | 7.88 | 8.04 |
Eyes lens | 1.07 | 7.54 | 8.07 |
Lymph | 1.03 | 7.84 | 8.07 |
Testis | 1.04 | 7.82 | 8.13 |
Brain | 1.04 | 7.88 | 8.19 |
Urinary bladder filled | 1.03 | 7.98 | 8.22 |
Kidney | 1.05 | 7.84 | 8.23 |
Ovary | 1.05 | 7.84 | 8.24 |
Muscle | 1.05 | 7.85 | 8.24 |
Lung deflated | 1.05 | 7.88 | 8.27 |
Skin | 1.09 | 7.63 | 8.31 |
Liver | 1.06 | 7.87 | 8.34 |
Spleen | 1.06 | 7.87 | 8.34 |
Heart | 1.06 | 7.95 | 8.43 |
Blood | 1.06 | 7.97 | 8.45 |
Cartillage | 1.10 | 8.33 | 9.16 |
Thyroid | 1.05 | 9.19 | 9.65 |
Spongiosa | 1.18 | 10.74 | 12.68 |
Sacrum | 1.29 | 11.46 | 14.79 |
Femur | 1.33 | 12.09 | 16.08 |
Humerus | 1.46 | 12.61 | 18.41 |
Cranium | 1.61 | 13.13 | 21.14 |
Mandible | 1.68 | 13.33 | 22.40 |
Cortical bone 5 year Child | 1.75 | 13.56 | 23.72 |
Cortical bone | 1.92 | 13.98 | 26.84 |
Validation of the tissue assignation method
Transmitted dose through known materials
Transmitted dose through a mouse
Results
HU calculation applied to acquisitions with a 40kVp uncollimated cone beam
“Dose-equivalent” tissue calculation
-
о for ρZeff < 10: carbon and oxygen.
-
о for ρZeff > 10: calcium and phosphor.
Validation of the tissue assignation method
Transmitted dose through known materials
Manufacturer’s data | ρZeff based tissue assignation method | ||||||||
---|---|---|---|---|---|---|---|---|---|
Tissue substitutes | EBT3 (Gy) | MC dose (Gy) | Stat. Uncert. | MC/EBT3 relative difference | MC/EBT3 absolute difference (Gy) | MC Dose (Gy) | Stat. Uncert. | MC/EBT3 relative difference | MC/EBT3 absolute difference (Gy) |
CT solid water | 4.58 | 4.61 | 1.4% | 0.5% | 0.03 | 4.51 | 1.3% | −1.5% | −0.07 |
Inner bone | 3.44 | 3.50 | 1.5% | 1.7% | 0.06 | 3.41 | 1.5% | −1.0% | −0.03 |
Cortical bone | 1.40 | 1.38 | 2.0% | −1.8% | −0.02 | 1.42 | 2.1% | 1.3% | 0.02 |
CB2 50% | 1.99 | 1.93 | 1.8% | −3.0% | −0.06 | 2.02 | 1.8% | 1.5% | 0.03 |
CB2 30% | 2.73 | 2.72 | 1.6% | −0.4% | −0.01 | 2.80 | 1.6% | 2.6% | 0.07 |
Breast | 4.93 | 4.91 | 1.3% | −0.4% | −0.02 | 4.75 | 1.3% | −3.6% | −0.18 |
B200-bone | 3.41 | 3.49 | 1.5% | 2.4% | 0.08 | 3.45 | 1.5% | 1.1% | 0.04 |
Adipose | 5.29 | 5.35 | 1.3% | 1.3% | 0.07 | 5.29 | 1.3% | 0.1% | 0.01 |