Swindell W
Ultrasound Med Biol. 1985 Jan-Feb;11(1):121-30. doi: 10.1016/0301-5629(85)90014-6.
This is a theoretical study of the absorbed power density that arises when a focused ultrasound beam is absorbed in a tissue-like medium. The specific application is selective tissue heating for cancer hyperthermia. Results are expressed in terms of an enhancement ratio which describes the fractional gain in absorbed power density when nonlinear effects are taken into account relative to the absorbed power density that results when only linear effects are considered. Starting from a standard configuration in which the transducer has a (Gaussian) diameter of 0.12 m, a radius of curvature of 0.16 m and an operating frequency of 1 MHz a numerical sensitivity analysis is performed in which transducer and tissue parameters are varied one at a time. Enhancement ratios are invariably greater than unity, often being in the range of 1.5-2 for regions near the focus of the beam. The prediction is that nonlinear effects will probably be useful in selectively increasing the temperature rise in the focal region of a focused applicator.
这是一项关于聚焦超声束在类组织介质中被吸收时产生的吸收功率密度的理论研究。具体应用是用于癌症热疗的选择性组织加热。结果以增强比来表示，该增强比描述了考虑非线性效应时吸收功率密度相对于仅考虑线性效应时所得吸收功率密度的分数增益。从换能器直径为0.12米（高斯分布）、曲率半径为0.16米且工作频率为1兆赫的标准配置开始，进行了数值灵敏度分析，其中每次改变一个换能器和组织参数。增强比总是大于1，对于束焦点附近的区域，通常在1.5 - 2的范围内。预测是非线性效应可能有助于选择性地提高聚焦施加器焦点区域的温度升高。
