Development of the measuring technique for ultrasonic attenuation distribution of tissues

生物组织中的声学特性提供了重要的诊断和治疗计划信息。传统的声速测定方法通常需要换能器与试样进行物理接触，以便在时域中测量厚度和超声信号。提出了一种用于确定声速和衰减的方法，其中，由于样品的存在，在频域中估计样品中的声音传播时间和从换能器到刚性反射器的总信号的差异，并且该方法不需要超声探头与活的或新鲜切除的组织标本的物理接触。利用这种方法，可以精确地测量人体心脏组织的声速和衰减。正常心脏中声音的速度和衰减在个体之间变化最小，并且与体重或年龄无关。心脏组织声速和衰减的变化与心脏的组织学改变有关。组织中超声传播速度和衰减的测量验证了该方法在医学应用中的有效性。

The acoustic characteristics in biological tissues provide important diagnostic and treatment planning information. Conventional methods of sound speed determination generally require that transducers make physical contact with specimens in order to measure thickness and ultrasonic signal in the time domain. A method for determination of the sound speed and attenuation is proposed in which the sound travel time in the sample and the difference in total signal from the transducer to the rigid reflector due to the presence of the sample are estimated in the frequency domain and which does not require physical contact of ultrasonic probes to living or freshly excised tissue specimens. Using this method, the sound speeds and attenuation of human heart tissues are measured precisely. The speed and attenuation of sound in normal hearts varied minimally between individuals and was not related to body weight or age. Change of sound speed and attenuation of heart tissues was associated with histological change of a heart. Ultrasonic speed and attenuation measurements in tissues verified the method validity in medical application.