Laser-enhanced particle-free HIFU heating

描述（由申请人提供）：高强度聚焦超声（HIFU）治疗已成为实体瘤治疗的真正非侵入性医疗程序。然而，单次HIFU超声处理后的病变体积很小。因此，消融相对较小的肿瘤可能需要长达几个小时。此外，由于血液循环的冷却作用，高度血管化（灌注）的组织比灌注不良的区域更耐热消融。因此，在高度血管化的组织中需要延长加热持续时间。在HIFU治疗后也经常观察到通常限于亚厘米浅表烧伤的皮肤烧伤，因为超声能量沉积在皮肤表面达到局部最大值。为了促进HIFU过程并避免或最小化皮肤灼伤，我们需要在相对低的超声强度水平下增强靶组织中的HIFU诱导加热。HIFU诱导加热的有效性与局部超声吸收有关。靶组织对超声吸收的增加可以有效地改善HIFU治疗的加热效果。已经研究了将超声造影剂或纳米颗粒注射到靶组织中作为增加局部超声吸收和增强HIFU加热的方法。在目前的项目中，我们建议评估光增强无颗粒技术，以促进HIFU消融。我们的中心假设是，可以通过诊断激光系统来改善HIFU治疗，而无需将任何微米或纳米颗粒注入体内。我们有两个具体目标：1）研究和优化光增强无颗粒HIFU加热：离体研究;和2）在啮齿动物模型中评价光增强无颗粒HIFU加热。我们相信，拟议的研究的成功将导致增强HIFU治疗实体肿瘤的治疗，其中包括乳腺肿瘤，前列腺肿瘤，头颈部癌症的治疗。

DESCRIPTION (provided by applicant): High intensity focused ultrasound (HIFU) therapy has emerged as a truly non-invasive medical procedure for solid tumor treatment. However, the volume of the lesion following a single HIFU sonication is small. As a result, it can take up to several hours to ablate a relatively small tumor. In addition, highly vascularized (perfused) tissues are more resistant to thermal ablation than poorly perfused areas owing to the cooling effect of blood circulation. Therefore, a prolonged heating duration will be required in highly vascularized tissues. Skin burns, which are usually limited to subcentimetre superficial burns, are also often observed after HIFU treatments because ultrasonic energy deposition reaches a local maximal at skin surface. To facilitate HIFU process and avoid or minimize skin burns, we need to enhance HIFU-induced heating in the targeted tissue at a relatively low ultrasound intensity level. The effectiveness of HIFU-induced heating is related to the local ultrasound absorption. The increase of ultrasound absorption in the targeted tissue can effectively improve the heating outcome of HIFU treatment. The injection of ultrasound contrast agents or nanoparticles into the targeted tissue has been studied as a method to increase the local ultrasound absorption and enhance HIFU heating. In the current project, we propose to evaluate a photo-enhanced particle-free technique to facilitate HIFU ablation. Our central hypothesis is that HIFU therapy can be improved by a diagnostic laser system without the injection of any micro-, or nano-particles into the body. We have two specific aims: 1) investigate and optimize photo- enhanced particle-free HIFU heating: ex vivo study; and 2) evaluate photo-enhanced particle-free HIFU heating in a rodent model. We believe that the success of the proposed research will lead to an enhanced HIFU therapy for solid tumor treatments, which include the treatment of breast tumors, prostate tumors, head and neck cancer.