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. Author manuscript; available in PMC: 2012 Oct 1.
Published in final edited form as: Ultrasound Med Biol. 2011 Aug 25;37(10):1734–1742. doi: 10.1016/j.ultrasmedbio.2011.06.010

Table 1.

Compendium of the operating details for use in ultrasonic microscopy, including basic equations of the SAM operating principles: axial and lateral resolutions, DOF, and acoustic impedance.

Equation Term Application
1. Rax=c2×BW Axial Resolution Resolution depends on the dimensions of the pressure pulse, which is related to the transducer bandwidth (BW) and system electronics, where c is the sound speed in the tissue and BW is 32MHz.
2. Rlat=λ × f-number Lateral Resolution Resolution at the focal point, where λ is the wavelength(25μm). Lateral resolution is the resolution orthogonal to the propagation direction of the ultrasound wave.
3. DOF=4(f-number)2 λ Depth of Field (DOF) Due to a small f-number(which provides a tight beamwidth), the DOF is also limited.
4. Z= ρc Acoustic Impedance Impedance (Z) determines the amplitude of the reflected and transmitted waves at the fluid- interface. Complex scattering properties of tissues are due to acoustic impedance interfaces in microstructure of tissues. ρ is the material density.
5. R = |(Z2−Z1)/(Z2+Z1)| Reflection Coefficient Ratio of the impedance mismatch between the two materials – fluid and tissue specimen.