Concepts of Ultrasound Physics
ULTRASOUND PHYSICS
Name
Institution
a) Calculate the Acoustic impedance of subcutaneous tissue, muscle and bone. Assume subcutaneous tissue has a density of 1060kg/m3 (Hedrick 2003), muscle has a density of 1104kg/m3 (Madjor 2008) and bone has a density of 5065kg/m3 (Hedrick 2003). Give your answer in Mrayls. Please use speed of sound as 1540m/s for tissue, muscle and bone
In ultrasound, Acoustic impedance (Z) is the quantity of measurement of resistance to sound when passing through a medium (Hedrick,Hykes&Starchman 2005, p.10).
According to Gill (2012,p. 11) the equation for Acoustic impedance is Z=ρc, where (Z=Acoustic impedance, ρ =density of medium and c =velocity of beam). From this equation is understood that acoustic impedance is the multiplication of density of tissue and the propagation speed. The unit of measurement Acoustic Impedance unit is named as Rayls (Kg//s) (Gill 2012,p. 11).
*(a) Hence the acoustic impedance of subcutaneous tissue with density of 1060kg/ and speed of sound in soft tissue is 1540m/s Z= pc Z= 1060(kg/x 1540(m/s) =1632400 rayls= 1.63Mrayls
Acoustic impedance of Muscle with density 1104kg/m3 with velocity 1540m/s Z= 1104(kg/) x 1540(m/s)
=1700160 rayls= 1.70Mrayls
Acoustic impedance of bone with density 5056kg/m3 with velocity 1540m/s Z =5065(kg/) x 1540 (m/s) =7800100 rayls= 7.80Mrayls
(B) Calculate the reflection coefficient and then the % reflection at a soft tissue / muscle interface and soft tissue / bone interface?
In ultrasound, the every sound wave is reflected regardless of the thickness of the material at an interface hence the equation of a reflection coefficient can be expressed as
* The reflection coefficient is expressed as R= where is the acoustic impedance of Medium 2 and is the acoustic impedance of medium one (1) respectively.
(Gill 2012, p 11)
And the % reflection is given by the formula =R x 100.
%
Name
Institution
a) Calculate the Acoustic impedance of subcutaneous tissue, muscle and bone. Assume subcutaneous tissue has a density of 1060kg/m3 (Hedrick 2003), muscle has a density of 1104kg/m3 (Madjor 2008) and bone has a density of 5065kg/m3 (Hedrick 2003). Give your answer in Mrayls. Please use speed of sound as 1540m/s for tissue, muscle and bone
In ultrasound, Acoustic impedance (Z) is the quantity of measurement of resistance to sound when passing through a medium (Hedrick,Hykes&Starchman 2005, p.10).
According to Gill (2012,p. 11) the equation for Acoustic impedance is Z=ρc, where (Z=Acoustic impedance, ρ =density of medium and c =velocity of beam). From this equation is understood that acoustic impedance is the multiplication of density of tissue and the propagation speed. The unit of measurement Acoustic Impedance unit is named as Rayls (Kg//s) (Gill 2012,p. 11).
*(a) Hence the acoustic impedance of subcutaneous tissue with density of 1060kg/ and speed of sound in soft tissue is 1540m/s Z= pc Z= 1060(kg/x 1540(m/s) =1632400 rayls= 1.63Mrayls
Acoustic impedance of Muscle with density 1104kg/m3 with velocity 1540m/s Z= 1104(kg/) x 1540(m/s)
=1700160 rayls= 1.70Mrayls
Acoustic impedance of bone with density 5056kg/m3 with velocity 1540m/s Z =5065(kg/) x 1540 (m/s) =7800100 rayls= 7.80Mrayls
(B) Calculate the reflection coefficient and then the % reflection at a soft tissue / muscle interface and soft tissue / bone interface?
In ultrasound, the every sound wave is reflected regardless of the thickness of the material at an interface hence the equation of a reflection coefficient can be expressed as
* The reflection coefficient is expressed as R= where is the acoustic impedance of Medium 2 and is the acoustic impedance of medium one (1) respectively.
(Gill 2012, p 11)
And the % reflection is given by the formula =R x 100.
%
References: Gill, R., 2012. The physics and technology of diagnostic ultrasound: a practitioner 's guide. Abbotsford, N.S.W.: High Frequency Publishing. Hedrick, W. R., & Hykes, D. L., 2005. Ultrasound physics and instrumentation (4th ed.). St. Louis, Mo.: Elsevier Mosby. Hilson, B., 2005. Ultrasound. Physics Today, 18(3), 113. Hoskins, P. R., 2003. Diagnostic ultrasound: physics and equipment. London: Greenwich Medical Media :. Huisman, H., 2004. Diagnostic ultrasound: Physics and equipment. Ultrasound in Medicine & Biology, 30(7), 1011. Miele, F. R., 2006. Ultrasound physics & instrumentation (4th ed.). Forney, TX: Miele Enterprises. Schirber, M., 2013. Ultrasound Signal Reveals Microstructure. Physics, 6, 102-112. Sprawls, P., 2013. Introduction and overview. Ultrasound Production and Interactions. Retrieved September 3, 2014, from http://www.sprawls.org/ppmi2/USPRO/ Zebski, J. A., 2006. Essentials of ultrasound physics. St. Louis: Mosby.