Attenuation Constant
The following table contains values for the acoustic attenuation of all tissues and includes statistical information on the standard deviation and the spread in the values.
For attenuation, a frequency dependence of the form α=α0*fb is assumed, where α (Np/m) is the absorption coefficient for a given frequency f, α0 (Np/m/Hz) is a medium constant, and b is also a numerical constant dependent on the tissue type. In the absence of information (e.g., data points that permit fitting) b is assumed to be 1. For the attenuation relationship, the parameters α and b are obtained by fitting the available data. Whenever a source provides a frequency dependence over a given frequency range, that function is sampled throughout the interval, with a ratio between neighboring frequencies of 1.2 to provide data points for the fit.
Frequency
| expBody ='';return 'Tissue' | 'Attenuation Constant (Np/m)' |
| expRow = d['B'+r];d['B'+r] | var freq=parseFloat($('#freqField').val())*parseFloat($('#scale').val()); var a0=parseFloat(d['BX'+r]); var b=parseFloat(d['BY'+r]); var att=a0*Math.pow(freq,b); expRow += "\t" + att + "\n"; if (d['B'+r] != null){ expBody += expRow }; return sprintf('%g',att) |
