NONINVASIVE DETERMINATION OF IN SITU HEATING RATE USING kHz ACOUSTIC EMISSIONS AND FOCUSED ULTRASOUND
NONINVASIVE DETERMINATION OF IN SITU HEATING RATE USING kHz ACOUSTIC EMISSIONS AND FOCUSED ULTRASOUND
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DOI：
10.1016/j.ultrasmedbio.2009.05.015
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发表时间：
2009-10-01
影响因子：
2.9
通讯作者：
Kaczkowski, Peter J.
中科院分区：
文献类型：
--
作者：
Anand, Ajay;Kaczkowski, Peter J.
为了使高强度聚焦超声（HIFU）广泛应用于临床，需要开发稳健的治疗计划、指导和实施方法。如果可以提供患者特定的组织参数作为输入，以便根据具体情况定制治疗计划和监测方案，这些技术将受益匪浅。本文提出了一种使用传热方程 (HTE) 并应用新颖的信号处理技术来估计局部原位声加热速率的非侵入性方法。加热速率是通过实验测量将治疗焦点的温度从基线温度升高到沸腾（此处假设水介质为 100 摄氏度）所需的时间，然后迭代求解传热方程以找到导致沸腾开始的加热速率而获得的。通过测量由于气泡剧烈破裂而在可听频率范围内声发射开始的时刻，可以无创地检测沸腾的开始。在模仿藻酸盐模型和切除的火鸡胸肌组织的组织中进行的体外实验表明，加热速率的无创估计与使用既定方法独立获得的估计非常一致。结果表明，这些技术在治疗计划和使用实时声反馈监测治疗剂量优化方面具有潜在的适用性。 （电子邮件：ajay.anand@philips.com） (C) 2009 年世界超声医学与生物学联合会。
For high-intensity focused ultrasound (HIFU) to be widely applicable in the clinic, robust methods of treatment planning, guidance and delivery need to be developed. These technologies would greatly benefit if patient specific tissue parameters could be provided as inputs so that the treatment planning and monitoring schemes are customized and tailored on a case by case basis. A noninvasive method of estimating the local in situ acoustic heating rate using the heat transfer equation (HTE) and applying novel signal processing techniques is presented in this article. The heating rate is obtained by experimentally measuring the time required to raise the temperature of the therapeutic focus from a baseline temperature to boiling (here assumed to be 100 degrees C for aqueous media) and then solving the heat transfer equation iteratively to find the heating rate that results in the onset of boiling. The onset of boiling is noninvasively detected by measuring the time instant of onset of acoustic emissions in the audible frequency range due to violent collapse of bubbles. In vitro experiments performed in a tissue mimicking alginate phantom and excised turkey breast muscle tissue demonstrate that the noninvasive estimates of heating rate are in good agreement with those obtained independently using established methods. The results show potential for the applicability of these techniques in therapy planning and monitoring for therapeutic dose optimization using real-time acoustic feedback. (E-mail: ajay.anand@philips.com) (C) 2009 World Federation for Ultrasound in Medicine & Biology.