| Mass density (g/cm3) | Electron density | |
| Air | 0.00 | 0.00 |
| Lung | 0.28 | 0.29 |
| Adipose | 0.94 | 0.93 |
| Breast | 0.98 | 0.96 |
| Water | 1.00 | 1.00 |
| Soft tissue | 1.02 | 1.01 |
| Muscle | 1.05 | 1.02 |
| Liver | 1.10 | 1.06 |
| Mineral bone | 1.15 | 1.10 |
| Cortical bone | 1.82 | 1.69 |