Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom.
Institute of Sound and Vibration Research, Faculty of Engineering and the Environment, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom.
J Acoust Soc Am. 2018 Oct;144(4):2490. doi: 10.1121/1.5063578.
It is proposed that the ultrasound frequency spectrum should be divided into three bands in order to facilitate a more rational assessment of its health effects. Whilst statement of the frequencies at the borders of these bands facilitates their definition, it is recognized that these observables vary continuously with frequency and consequently these border frequencies should not be used to rule out the possibility of a given effect occurring. The lowest band, US(A), lies between 17.8 and 500 kHz. In this band acoustic cavitation and its associated forces form the dominant process resulting in biological effects in liquids and soft tissues, whereas health effects from airborne ultrasound have been reported but are far less researched. In the middle band, US(B), between 500 kHz and 100 MHz, temperature rise in tissues becomes the most important biological effect of exposure. The highest band, US(C), covers frequencies above 100 MHz, for which the radiation force becomes an increasingly important biophysical mechanism. A justification for the selection of 17.8 kHz in preference to any other threshold for the lower frequency limit for ultrasound is given.
为了更合理地评估超声的健康影响，建议将超声频谱分为三个波段。虽然给出这些波段边界频率有助于对其进行定义，但也认识到这些可观察量随频率连续变化，因此不应使用这些边界频率来排除给定效应发生的可能性。最低波段 US(A)位于 17.8 至 500 kHz 之间。在这个波段，声空化及其相关力形成了在液体和软组织中产生生物效应的主要过程，而空气中超声的健康影响虽然已有报道，但研究得较少。在中间波段 US(B)，频率范围为 500 kHz 至 100 MHz，组织温升成为暴露的最重要的生物效应。最高波段 US(C)覆盖 100 MHz 以上的频率，辐射力成为越来越重要的生物物理机制。本文给出了选择 17.8 kHz 作为超声低频限值而不是其他任何阈值的理由。
