Curley M G
Acuson, Mountain View, CA.
IEEE Trans Ultrason Ferroelectr Freq Control. 1993;40(1):59-66. doi: 10.1109/58.184999.
An acoustic-thermal model was developed for scanned diagnostic ultrasound in soft tissue. An adiabatic surface between the transducer and the skin was justified, and the model accounted for attenuation and focusing. The temperature along the central plane of the temporally averaged acoustic field was calculated by integration of line sources of heat that result from the tissue's absorption of ultrasound. The temperature profiles were calculated for 1400 transducers. The results show that current diagnostic transducers heat more significantly at the transducer-tissue interface than at the focus. The temperature rise in the focal region is typically less than 25% of that at the surface. The acoustic power per scan length that results in a 1 degrees C temperature rise at the surface is calculated as (210 mW-MHz/cm)/f. These results apply to both linear arrays and sectorlike scan formats. The temperature rises for simultaneous multimode scanned beams are additive as the peak temperatures of each mode will occur on the surface. Consideration was given to the surface boundary condition for such models. This boundary is considered adiabatic for calculation of heating due to acoustic absorption alone. Additional heating or cooling resulting from the transducer can then be superimposed on this solution.
针对软组织中的扫描诊断超声开发了一种声热模型。论证了换能器与皮肤之间存在绝热表面，该模型考虑了衰减和聚焦。通过对组织吸收超声产生的线热源进行积分，计算了时间平均声场中心平面上的温度。计算了1400个换能器的温度分布。结果表明，当前的诊断换能器在换能器 - 组织界面处的发热比在焦点处更显著。焦点区域的温度升高通常小于表面温度升高的25%。导致表面温度升高1℃的每扫描长度的声功率计算为(210 mW - MHz/cm)/f。这些结果适用于线性阵列和扇形扫描格式。对于同时进行的多模式扫描波束，由于每个模式的峰值温度将出现在表面，温度升高是相加的。考虑了此类模型的表面边界条件。仅为计算由于声吸收引起的加热，该边界被视为绝热的。然后可以将换能器产生的额外加热或冷却叠加到该解上。
