Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA; Physics Faculty, Lomonosov Moscow State University, Moscow, Russia.
Physics Faculty, Lomonosov Moscow State University, Moscow, Russia.
Ultrasound Med Biol. 2023 Jan;49(1):62-71. doi: 10.1016/j.ultrasmedbio.2022.07.014. Epub 2022 Oct 4.
Boiling histotripsy (BH) is a focused ultrasound technology that uses millisecond-long pulses with shock fronts to induce mechanical tissue ablation. The pulsing scheme and mechanisms of BH differ from those of cavitation cloud histotripsy, which was previously developed for benign prostatic hyperplasia. The goal of the work described here was to evaluate the feasibility of using BH to ablate fresh ex vivo human prostate tissue as a proof of principle for developing BH for prostate applications. Fresh human prostate samples (N = 24) were obtained via rapid autopsy (<24 h after death, institutional review board exempt). Samples were analyzed using shear wave elastography to ensure that mechanical properties of autopsy tissue were clinically representative. Samples were exposed to BH using 10- or 1-ms pulses with 1% duty cycle under real-time B-mode and Doppler imaging. Volumetric lesions were created by sonicating 1-4 rectangular planes spaced 1 mm apart, containing a grid of foci spaced 1-2 mm apart. Tissue then was evaluated grossly and histologically, and the lesion content was analyzed using transmission electron microscopy and scanning electron microscopy. Observed shear wave elastography characterization of ex vivo prostate tissue (37.9 ± 22.2 kPa) was within the typical range observed clinically. During BH, hyperechoic regions were visualized at the focus on B-mode, and BH-induced bubbles were also detected using power Doppler. As treatment progressed, hypoechoic regions of tissue appeared, suggesting successful tissue fractionation. BH treatment was twofold faster using shorter pulses (1 ms vs. 10 ms). Histological analysis revealed lesions containing completely homogenized cell debris, consistent with histotripsy-induced mechanical ablation. It was therefore determined that BH is feasible in fresh ex vivo human prostate tissue producing desired mechanical ablation. The study supports further work aimed at translating BH technology as a clinical option for prostate ablation.
沸腾空化射流（BH）是一种利用毫秒级长脉冲和激波阵面诱导机械组织消融的聚焦超声技术。与之前用于治疗良性前列腺增生的空化云射流不同，BH 的脉冲方案和机制也有所不同。本文的工作旨在评估使用 BH 消融新鲜离体人前列腺组织的可行性，作为将 BH 技术开发用于前列腺应用的原理验证。通过快速尸检（死亡后<24 小时，机构审查委员会豁免）获得新鲜人前列腺样本（N=24）。使用剪切波弹性成像对样本进行分析，以确保尸检组织的机械性能具有临床代表性。使用 10 或 1 ms 脉冲，1%占空比，在实时 B 型和多普勒成像下对 BH 进行曝光。通过间隔 1mm 的 1-4 个矩形平面进行超声处理，每个平面包含间隔 1-2mm 的焦点网格，从而创建体积损伤。然后对组织进行大体和组织学评估，并使用透射电子显微镜和扫描电子显微镜分析损伤内容物。离体前列腺组织的观察到的剪切波弹性成像特征（37.9±22.2kPa）处于临床观察到的典型范围内。在 BH 期间，在 B 模式上在焦点处观察到高回声区域，并且还使用功率多普勒检测到 BH 诱导的气泡。随着治疗的进行，出现了低回声组织区域，表明成功地进行了组织分割。使用较短的脉冲（1ms 与 10ms），BH 处理速度提高了两倍。组织学分析显示含有完全均质化细胞碎片的损伤，与射流诱导的机械消融一致。因此，确定 BH 在新鲜离体人前列腺组织中是可行的，可以产生所需的机械消融。该研究支持进一步将 BH 技术转化为前列腺消融的临床选择的工作。
