Spontaneous homogeneous nucleation, inertial cavitation and the safety of diagnostic ultrasound
Spontaneous homogeneous nucleation, inertial cavitation and the safety of diagnostic ultrasound
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DOI：
10.1016/s0301-5629(02)00579-3
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发表时间：
2002-10-01
影响因子：
2.9
通讯作者：
Church, CC
中科院分区：
文献类型：
--
作者：
Church, CC
在界面张力非常低的区域，可以在组织中自发形成足够大的气泡作为空化核。在没有声波或其他机械应力的情况下，这种核会迅速溶解并从介质中消失。然而，在声波的影响下，这些微泡可能会增长到初始尺寸的许多倍，然后猛烈地坍缩，这一过程被称为惯性空化。在这项工作中，通过将组织视为均匀流体来模拟成核-空化过程的体内能量学和动力学。假设黏度为10(-3)Pa s（即水的黏度），导致成核空化事件的最低声分压力阈值，接近4.0 MPa，在1至15 MHz范围内基本上与频率无关。黏度为5 × 10(-3) Pa s（血液）的稀薄压力阈值在1 MHz时也为-4.0 MPa，但这种高黏度的阈值随着频率高于类似于5 MHz的频率而几乎线性增加，从未超过0.2 MPa，低于假设MI = 1.9（当前USFDA指南）计算的等效降额峰值稀薄压力。（E-mail: cchurch@olemiss.edu） (C) 2002年世界超声医学生物学联合会。
Gas bubbles of sufficient size to serve as cavitation nuclei may form spontaneously in tissue in regions of very low interfacial tension. In the absence of an acoustic wave or other mechanical stress, such nuclei will quickly dissolve and disappear from the medium. Under the influence of an acoustic wave, however, these microbubbles may grow to many times their initial size and then collapse violently, a process known as inertial cavitation. In this work, the in vivo energetics and dynamics of the nucleation-cavitation process were modeled by treating tissue as a homogeneous fluid. The assumption of a viscosity of 10(-3) Pa s (i.e., that of water) resulted in the lowest acoustic rarefactional pressure threshold for nucleation-cavitation events, similar to4.0 MPa, which was essentially frequency-independent over the range 1 to 15 MHz. The rarefactional pressure threshold for a viscosity of 5 x 10(-3) Pa s (that of blood) also was -4.0 MPa at 1 MHz, but the threshold for this higher viscosity increased nearly linearly with frequency above similar to5 MHz, never being more than similar to0.2 MPa below the equivalent derated peak rarefactional pressure calculated assuming MI = 1.9, the current USFDA guideline. (E-mail: cchurch@olemiss.edu) (C) 2002 World Federation for Ultrasound in Medicine Biology.