- Velocity (propagation speed) is the speed through a given medium
- It is determined solely by the characteristics of the medium:
- It does not depend on the source of sound or its frequency
- The density and compressibility of a medium are the key determinants
- Each body tissue has a unique velocity determined by individual characteristics
- Machines commonly use an average value of 1,540 m/sec for soft tissue in depth calculations
Tissue
Velocity (m/s)
Air
331
Muscle
1,585
Fat
1,450
Soft Tissue (Average)
1,540