Precisely Shaped Acoustic Ablation of Tumors Under 3D Ultrasound Image Guidance

描述(申请人提供)：最近的许多研究证明了间质消融治疗肝脏肿瘤的有效性，包括使用射频、激光、微波或聚焦超声等能源进行化学消融、冷冻消融和热消融。尽管有这些有希望的结果，但目前的系统仍然高度依赖于操作员的技能，无法治疗许多肿瘤，因为几乎不能控制坏死区的大小和形状，也无法控制组织内的消融器轨迹。要解决这一问题，需要改进末端执行器的设计，将消融器装置精确地引导到所需的目标位置，并实时监测坏死区，以确保完全治疗。术中超声成像可能提供了最佳和最容易获得的靶向方法，但同时手动处理B型超声(US)探头和消融器设备是一项具有挑战性的任务，即使在最有经验的医生手中也容易出现重大错误。组织变形和靶点运动使得将消融器装置精确地放置到靶区变得极其困难。不规则形状的靶区通常需要多次插入和几个重叠的热损伤，要在不对周围正常组织造成过度损害的情况下准确和及时地完成这些任务甚至更具挑战性。为了回答这些问题，我们建议开发一种创新的方法，用于在不依赖外部跟踪设备的情况下，对空间注册的手术中美国体积进行准确跟踪和工具注册。这种三维超声(3DUS)将与一种名为主动插管(AC)的灵活、蛇形、轻便且廉价的机器人集成在一起，以便于将可控制的超声热消融器精确放置到肝脏中，并通过实时3D注册超声监控组织消融的进展。植入式或间质性高功率超声辐射器的最新发展显示出极具可控性和穿透性的加热模式，这种加热模式可以成形和动态改变，为符合条件的热手术提供了理想的机制。这种可控性和穿透性是非常可取的，将大大改进现有的射频和微波(MW)技术用于肝肿瘤的微创热消融。然而，到目前为止，对这项微创技术的广泛评估主要限于活体犬前列腺和中等灌流组织，还没有包括治疗高灌流肝组织内肿瘤所需的设计迭代和彻底评估。来自肝脏热疗的初步热疗数据(C部分)令人鼓舞。超声间质热疗(USITT)技术前景看好，我们将推广该技术以优化其在肝肿瘤治疗中的应用。这项研究和开发的总体目标是提供一个真正的闭环系统，用于指导、放置、引导、经皮适形消融治疗和在线监测治疗。

DESCRIPTION (provided by applicant): Many recent studies have demonstrated the efficacy of interstitial ablative approaches for the treatment of hepatic tumors, including chemical ablation, cryoablation, and thermal ablation using energy sources like RF, laser, microwave, or focused ultrasound. Despite these promising results, current systems remain highly dependent on operator skill, and cannot treat many tumors because there is little control of the size and shape of the zone of necrosis, and no control over ablator trajectory within tissue. Remedying this problem requires advances in end-effector design, precise steering of the ablator device to the desired target location, and real- time monitoring of the zone of necrosis to ensure complete treatment. Intra-procedure ultrasound imaging provides perhaps the optimal and most readily available method for targeting, but simultaneous manual handling of the B-mode ultrasound (US) probe and the ablator device is a challenging task that is prone to significant errors in the hands of even the most experienced physicians. Tissue deformation and target motion make it extremely difficult to place the ablator device precisely into the target. Irregularly shaped target volumes typically require multiple insertions and several overlapping thermal lesions, which are even more challenging to accomplish in a precise and timely manner without causing excessive damage to surrounding normal tissues. In answer to these problems, we propose to develop an innovative method for accurate tracking and tool registration with respect to spatially-registered intaoperative US volumes without relying on an external tracking device. This three-dimensional ultrasound (3DUS) will be integrated with a flexible, snake-like lightweight and inexpensive robotic, called the Active Cannula (AC), to facilitate precise placement of a steerable ultrasound thermal ablator into the liver and to monitor the progress of tissue ablation with real-time 3D registered ultrasound. Recent developments of implantable or interstitial high-power ultrasound applicators have demonstrated extremely controllable and penetrating heating patterns which can be shaped and dynamically altered, providing an ideal mechanism for conformable thermal surgery. This controllability and penetration is highly desirable and would provide significant improvement over existing RF and microwave (MW) technology used for minimally invasive thermal ablation of liver tumors. However, to date the extensive evaluation of this minimally invasive technology has been limited mostly to in vivo canine prostates and moderately perfused tissues, and have not included the design iterations and thorough evaluations necessary for treating tumors within highly perfused liver tissue. The preliminary thermal data from thermal therapy of perfused liver (Section C) are encouraging. Ultrasound Interstitial Thermal Therapy (USITT) technology is promising and we will extend the technology to optimize its use for the treatment of hepatic tumors. The overall goal of this research and development is to provide a true closed-loop system for steering, placement, guidance, percutaneous delivery of conformal ablative therapy, and on-line monitoring of treatment.