Table A2.

Relevant acoustic properties of selected materials/media. Sound velocity was calculated via $\mathrm{c}=\sqrt{\mathrm{E} (1 - \nu )/(\mathsf{\rho } \left(1 - \nu - 2{\nu }^2\right))}$ or $\mathrm{c}=\sqrt{1/(\mathsf{\chi } \mathsf{\rho })}$, respectively, for each material (except skin, fat and muscle tissue) with the characteristics in Table A1. For bone, the mean of the given parameter ranges was chosen. Acoustic impedance was calculated through $\mathrm{Z}=\mathsf{\rho } \mathrm{c}$ for all materials.

Material/Medium	Longitudinal Sound Velocity c m/s	Acoustic Impedance Z MNs/m3	Attenuation Coefficient α dB/(cm MHz)
Aluminum	6315	17.1	0.014 … 0.15 [41]
Titanium (alloy)	6522	27.1	0.15 … 0.70 [41]
Cobalt–chrome–molybdenum	6256	51.9	−
Bone (Substantia corticalis)	3432	6.50	1 … 10 [38]
Aqualene®	1616	1.49	2.8 dB/cm at 5 MHz
Water (20 °C)	1460	1.46	0.002 [42]
Glycerin	1899	2.39	−
Skin tissue	1730 [40]	1.99	−
Fat tissue	1460 [42]	1.39	0.8 [42]
Muscle tissue	1580 [42]	1.68	1.2 [42]