Controlled tissue emulsification produced by high intensity focused ultrasound shock waves and millisecond boiling
Controlled tissue emulsification produced by high intensity focused ultrasound shock waves and millisecond boiling
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DOI：
10.1121/1.3626152
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发表时间：
2011-11-01
影响因子：
2.4
通讯作者：
Bailey, Michael R.
中科院分区：
文献类型：
--
作者：
Khokhlova, Tatiana D.;Canney, Michael S.;Bailey, Michael R.
在高强度聚焦超声 (HIFU) 应用中，组织可能会因加热而热坏死、因空化而乳化，或者正如最近发现的那样，可能会因冲击波加热引起的重复毫秒沸腾而被乳化。在这里，对最后一种方法进行了进一步研究。使用 1、2 和 3 MHz 聚焦传感器和不同的脉冲方案（其中压力、占空因数和脉冲持续时间各不相同）在透明凝胶和离体牛心脏组织中进行实验。先前开发的用于确定原位冲击幅度和沸腾时间的降额程序得到了改进。使用 B 型超声监测治疗。在暴露过程中观察到惯性空化和沸腾，但乳化仅在存在冲击和沸腾时发生。产生无热变性的乳化损伤，冲击幅度足以在小于 20 毫秒内引起沸腾，占空因数小于 0.02，脉冲长度短于 30 毫秒。较高的占空因数或较长的脉冲会产生不同程度的热变性以及机械乳化。使用较低的超声频率获得较大的病变。结果表明，冲击波加热和毫秒沸腾是一种有效且可靠的乳化组织方法，同时用超声波监测治疗情况。 (C) 2011 年美国声学学会。 [DOI：10.1121/1.3626152]
In high intensity focused ultrasound (HIFU) applications, tissue may be thermally necrosed by heating, emulsified by cavitation, or, as was recently discovered, emulsified using repetitive millisecond boiling caused by shock wave heating. Here, this last approach was further investigated. Experiments were performed in transparent gels and ex vivo bovine heart tissue using 1, 2, and 3 MHz focused transducers and different pulsing schemes in which the pressure, duty factor, and pulse duration were varied. A previously developed derating procedure to determine in situ shock amplitudes and the time-to-boil was refined. Treatments were monitored using B-mode ultrasound. Both inertial cavitation and boiling were observed during exposures, but emulsification occurred only when shocks and boiling were present. Emulsified lesions without thermal denaturation were produced with shock amplitudes sufficient to induce boiling in less than 20 ms, duty factors of less than 0.02, and pulse lengths shorter than 30 ms. Higher duty factors or longer pulses produced varying degrees of thermal denaturation combined with mechanical emulsification. Larger lesions were obtained using lower ultrasound frequencies. The results show that shock wave heating and millisecond boiling is an effective and reliable way to emulsify tissue while monitoring the treatment with ultrasound. (C) 2011 Acoustical Society of America. [DOI: 10.1121/1.3626152]