On the Ultrasound Scattering from Blood as a Function of Hematocrit
On the Ultrasound Scattering from Blood as a Function of Hematocrit
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关于血液中的超声散射作为血细胞比容的函数
DOI：
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发表时间：
1982
期刊：
影响因子：
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通讯作者：
K. Shung
中科院分区：
文献类型：
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作者：
K. Shung
测量了血液的体积超声散射系数，定义为单位红细胞体积散布功率和单位入射强度随频率和红细胞压积的函数关系。在所研究的所有频率中，实验散射峰出现在红细胞压积在20%到30%之间。TLIS与特沃斯基早期的假设独立散射体并预测最大50%的散射体的理论不太一致。这一假设当然不适用于红细胞体积分数较大(红细胞压积大于8%)的血液。为了考虑大分数体积散射体之间的相互作用，必须指定散射体位置的对分布函数。关于这个函数，人们已经提出了许多近似公式。Twersky利用统计力学中的定理导出的对分布函数，也可以从Percus-Yevick方程得到，用来描述超声在血液上的散射实验数据。结果表明，散射峰从50%的红细胞压积向较低的红细胞压积移动并不是意外的，可以用散射体之间的相互作用来解释。
Volumetric ultrasonic scattering coefficient for blood defined as rhe power scattered per unit volume of erythrocytes per unit incident intensity has been measured as a function of frequency and hematocrit. An experimental scattering peak was observed to occur at a hematocrit between 20 percent and 30 percent for all frequencies investigated. Tlis is not in good agreement with Twersky’s earlier t h e e ries which assumed independent scatterers and predicted a maximum a t 50 percent. This assumption certainly does not apply to blood with large fractional volume of erythrocytes (hematocrit greater than 8 percent). To consider interactions among scatterers at large fractional volume, pair distribution function of scatterer positions must be specified. A number of approximations for this function have been developed. Pair distribution functions derived by Twersky using t h e e rems in statistical mechanics, which also could be obtained from Percus-Yevick equation, are used to describe the experimental ultrasonic scattering data on blood. It is shown that the shift of the scattering peak from a hematocrit of 50 percent to lower hematocrits is not unexpected and could be explained in terms of the interaction among scatterers