ULTRASONIC-ATTENUATION AND ABSORPTION IN LIVER-TISSUE
ULTRASONIC-ATTENUATION AND ABSORPTION IN LIVER-TISSUE
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DOI：
10.1016/0301-5629(83)90089-3
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发表时间：
1983-01-01
影响因子：
2.9
通讯作者：
PARKER, KJ
中科院分区：
文献类型：
--
作者：
PARKER, KJ
在文献中报道了组织的超声衰减系数和吸收系数的很大范围的值。实际和理论上的一个重要区别是真实吸收的大小，它表征了超声波到热能的转换率，与超声信号在组织中传播时的总衰减相比。这些量的大小是在牛肝脏中研究的。用相敏和相不敏感插入损耗技术测量了1-6 MHz范围内的总衰减量。用两种热法测定其超声吸收。采用了标准的瞬时热电或升温速率法和一种基于短脉冲超声后温度衰减的新的测量技术来测量超声吸收系数。结果表明，在低兆赫频率下，肝脏的超声振幅、衰减和吸收系数没有显著差异。平均值约为每兆赫0.05个尼珀/厘米(每兆赫0.4分贝/厘米)。样品之间的差异由测量结果的标准偏差表示，每兆赫0.01nepers/cm(每兆赫0.09分贝/厘米)或更低。在肝组织中，吸收是该频率范围内衰减的主要特征。
A large range of values for ultrasonic attenuation and absorption coefficients of tissues are reported in the literature. An important distinction both practically and theoretically is the magnitude of the true absorption, which characterizes the rate of conversion of ultrasonic to thermal energy, as compared with the total attenuation of the ultrasonic signal as it propagates through tissue. The magnitudes of these quantities were studied in bovine liver. Total attenuation was measured, in the range of 1-6 MHz, by both phase sensitive and phase insensitive insertion loss techniques. Ultrasonic absorption was determined by 2 thermal techniques. The standard transient thermoelectric or rate-of-heating method and a new measurement technique based on the temperature decay following a short ultrasonic pulse were employed for the determination of the ultrasonic absorption coefficient. The results demonstrate that the ultrasonic amplitude attenuation and absorption coefficients at low megahertz frequencies are not significantly different in liver. The mean values cluster around 0.05 nepers/cm per MHz (0.4 dB/cm per MHz). The sample-to-sample variation is indicated by the standard deviation in the measurements of 0.01 nepers/cm per MHz (0.09 dB/cm per MHz) or less. In liver tissue, absorption is the dominant feature of attenuation over this frequency range.