MEASUREMENTS OF CALF LIVER ULTRASONIC DIFFERENTIAL AND TOTAL SCATTERING CROSS-SECTIONS
MEASUREMENTS OF CALF LIVER ULTRASONIC DIFFERENTIAL AND TOTAL SCATTERING CROSS-SECTIONS
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DOI：
10.1121/1.390534
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发表时间：
1984-01-01
影响因子：
2.4
通讯作者：
WAAG, RC
中科院分区：
文献类型：
--
作者：
CAMPBELL, JA;WAAG, RC
测量并归一化来自小牛肝脏的超声散射以获得每单位体积的平均微分散射截面[. hivin. sigma.sd（. nu.）]在散射角上大小范围从25 °到25 °。至165度。频率在3到7 MHz之间。在每个测量的频率下，小牛肝脏是弱散射体，其总散射功率的近1/2指向25 °之间。和45度。. hivin的值。sigma.sd（165.degree.），预计与. hivin没有太大区别。sigma.sd（180.degree.），后向散射系数为λ。3.7. times. 10-6f1.4/mm/Ω，其中f以MHz为单位，Ω为单位。球面度。通过整合. hivin.. sigma.sd在所有测量的散射角上找到总散射截面。sigma.st，散射损耗对衰减的贡献为. apprx。2%的频率。. hivin的形状分析sigma.sd表明，肝脏的相关长度约为1 mm。为了评估标准化方法的准确性，hivin的实验和理论结果。sigma.st上的参考培养基进行比较，发现差异<10%。
Ultrasonic scattering from calf liver was measured and normalized to obtain the average differential scattering cross section per unit volume [.hivin..sigma.sd (.nu.)] over scattering angles .nu. ranging in magnitude from 25.degree. to 165.degree. and frequencies between 3 and 7 MHz. At each of the measured frequencies, calf liver is a weak scatterer with nearly 1/2 of the total scattered power directed between 25.degree. and 45.degree.. The value of .hivin..sigma.sd (165.degree.), which is not expected to differ much from .hivin..sigma.sd (180.degree.), the backscattering coefficient, was .apprx. 3.7 .times. 10-6f1.4/mm per .OMEGA., with f in MHz and .OMEGA. in steradians. By integrating .hivin..sigma.sd over all the measured scattering angles to find the total scattering cross section .hivin..sigma.st, the contribution of scattering loss to attenuation was .apprx. 2% over the measured frequencies. Analysis of the shape of .hivin..sigma.sd suggests that the correlation length of the liver was on the order of 1 mm. To assess the accuracy of the normalization method, experimental and theoretical results for .hivin..sigma.st of a reference medium consisting of glass spheres in agar were compared and found to differ by < 10%.