Laser-enhanced particle-free HIFU heating

描述（由申请人提供）：高强度聚焦超声（HIFU）治疗已经成为一种真正的非侵入性治疗实体肿瘤的医疗程序。然而，单次HIFU超声检查后病变的体积很小。因此，切除一个相对较小的肿瘤可能需要几个小时。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组织更能抵抗热消融。因此，在高度血管化的组织中需要延长加热时间。由于超声能量沉积在皮肤表面达到局部最大值，HIFU治疗后也经常观察到皮肤烧伤，通常仅限于亚厘米的浅表烧伤。为了促进HIFU过程，避免或尽量减少皮肤烧伤，我们需要在相对较低的超声强度水平下增强HIFU诱导的靶组织加热。hifu诱导加热的有效性与局部超声吸收有关。靶组织超声吸收的增加可以有效改善HIFU治疗的加热效果。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，我们建议评估一种光增强无粒子技术，以促进HIFU消融。我们的中心假设是，在不向体内注射任何微或纳米颗粒的情况下，诊断激光系统可以改善HIFU治疗。我们有两个具体的目标：1)研究和优化光增强无粒子HIFU加热：离体研究；2)在啮齿动物模型中评估光增强无颗粒HIFU加热。我们相信，该研究的成功将导致HIFU治疗实体肿瘤的增强，包括乳腺肿瘤、前列腺肿瘤、头颈癌的治疗。

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.