Fast volumetric treatment using multi-focus insonation and thermal amplification

 描述（由申请人提供）：磁共振成像引导的聚焦超声（MRgFUS）已显示出作为侵入性手术替代方案的前景，用于越来越多的临床应用，包括治疗子宫肌瘤、缓解骨转移疼痛和治疗神经系统疾病。虽然该手术上级传统的侵入性手术，但这种治疗的持续时间会带来显著的成本和不适 对患者来说，在许多情况下减少了实际实施和影响。在这个应用中，我们提出了一种双重方法，使用多焦点超声波结合相变纳米液滴，以显着提高治疗时间。多焦点声处理是使用阵列换能器来创建具有多个高强度位置的焦点图案的过程， 比单焦点更有效地加热组织。我们试图将这种超声方法与纳米液滴结合起来，纳米液滴在激活时选择性地放大超声的热效应。这些颗粒在注入时处于液态，但在经受高压声脉冲时经历相变成微泡。因此，仅多个焦点周围的组织中的纳米液滴将经历相变，导致在该大的多焦点体积处的大量热能和机械能放大。同时，在聚焦区之外的纳米液滴将不会经历它们的声学激活阈值，并且将保持在声学休眠液体状态，从而避免在声学焦点之外的组织中的热放大，从而保护健康组织。我们假设，多焦点超声和相变纳米液滴的组合将使MRgFUS的使用能够比目前可用的方法快三倍地治疗临床相关体积，同时保持对治疗区域边缘的精确控制。这种改进将显著减少MRgFUS当前临床应用所需的时间，并将其作用扩展到需要治疗大体积但不可行的应用中。

 DESCRIPTION (provided by applicant): Magnetic resonance imaging-guided focused ultrasound (MRgFUS) has shown promise as an alternative to invasive surgery for a growing number of clinical applications, including treatment of uterine fibroids, palliation of pain from bone metastases, and treatment of neurological disorders. Although the procedure is superior to traditional invasive surgery, the duration of this treatment incurs significant cost and discomfort for patients, reducing practical implementation and impact in many cases. In this application, we propose a dual approach using multi-focus insonation in conjunction with phase change nanodroplets to dramatically improve treatment times. Multi-focus insonation is the process of using an array transducer to create a focal pattern with multiple high intensity locations that can heat tissue more efficiently than is possible with a single focus. We seek to combine this insonation method with nanodroplets that selectively amplify the thermal effects of ultrasound when activated. These particles are in a liquid state when injected but undergo phase change to microbubbles when subjected to a high-pressure acoustic pulse. Therefore, only nanodroplets in the tissue surrounding the multiple foci will undergo phase change, resulting in substantial thermal and mechanical energy amplification at this large multi-focus volume. At the same time, nanodroplets outside of the focal zone will not experience their acoustic activation threshold and will remain in the acoustically dormant liquid state, thereby avoiding thermal amplification in tissues outside of the acoustic focus, sparing healthy tissue. We hypothesize that the combination of multi-focus ultrasound and phase change nanodroplets will enable the use of MRgFUS to treat a clinically relevant volume three times faster than currently available methods while maintaining precise control over the margins of the treated region. Such an improvement would significantly reduce the time required for current clinical applications of MRgFUS and expand its role into applications where treatment of large volumes is desired but not feasible.