Table 1 Physical properties of media
From: Effects of breast structure on high-intensity focused ultrasound focal error
| Skin | Fibroglandular | Fat | Water | |
|---|---|---|---|---|
| Density (kg/m3) | 1090 | 1032 | 985 | 998.2 |
| Sound speed (m/s) | 1615 | 1547 | 1465 | 1482 |
| Characteristic impedance (× 106 Pa.s/m) | 1.760 | 1.597 | 1.443 | 1.479 |
| Attenuation coefficient (dB/m/MHz) | – | 60 | 40 | 0.22 |