ULTRASONIC ABSORPTION BY BIOLOGICAL MATERIALS

进行研究，以获得详细的了解超声波 生物系统的传播特性，并立即强调 哺乳动物超声波吸收、衰减和速度弥散 组织和器官以及重要的生物学物质的溶液和悬浮液中， 大分子 具体目标是：（1）测量吸收和 超声波在组织和生物聚合物溶液中的速度，（2） 确定对描述观测到的 行为，（3）定量解释的现象， 放松和/或其他过程，以及（4）继续发展适当的 仪器，以获得必要的实验数据。 实现 这些目标有助于理解的物理机制 声音和生物系统的相互作用，这必须在 超声技术的全部潜力将在医疗领域得到实现。 诊断和治疗应用以及用于生物化学和生物物理 快速反应的研究。 调查结果还 与临床的毒性作用和剂量学有关 超声. 最近的发现包括水和结构蛋白的作用 在确定传播特性时， 在宽的温度和频率范围内，肺的传播特性， 自溶和固定对衰减、散射和速度的影响， 浓度对吸收的影响，以及小的 用于测定吸收和速度的体积共振仪器。

Studies are conducted to obtain detailed understanding of the ultrasonic propagation properties of biological systems, with immediate emphasis on ultransonic absorption, attenuation, and velocity dispersion in mammalian tissues and organs and in solutions and suspensions of important biological macromolecules. Specific objectives are: (1) measurement of absorption and velocity of ultrasonic waves in tissues and in solutions of biopolymers, (2) identification of the physical parameters important for describing the observed behavior, (3) quantitative interpretation of the phenomena in terms of relaxation and/or other processes, and (4) continued development of appropriate instrumentation for obtaining the necessary experimental data. The attainment of these objectives contributes to an understanding of the physical mechanisms of interaction of sound and biological systems, which must be elucidate before the full potential of the ultrasonic techniques will be realized for medical diagnostic and therapeutic applications and for biochemical and biophysical investigation of fast reactions. The results of the investigations also contribute important associated with toxic effects and dosimetry of clinical ultrasound. Recent findings include the role of water and structural proteins in determining the propagation properties, in vivo measurements of absorption over wide ranges of temperature and frequency, propagation properties of lung, the influence of autolysis and fixation on attenuation, scattering and velocity, the influence of concentration on absorption, and the development of a small volume resonant instrument for determining absorption and velocity.