MR-Guided Precision Conformal Ablation Therapy for Brain Tumors

描述（由申请人提供）：本项目的目标是开发一个集成系统，用于mri引导下的间质性高强度聚焦超声（iHIFU）精确定位和精确消融脑肿瘤。25-40%的系统性癌症患者遭受脑转移（BM）的影响。脑转移的治疗通常是多学科的，包括开放手术、立体定向放射外科（SRS）、全脑放疗和/或化疗。一部分患者是开放手术和/或SRS的候选者。在适当的患者中，通过开颅进行开放手术可以进行组织诊断，快速缓解症状和局部疾病控制。SRS的优点是它是非侵入性的，避免了开颅手术相关的并发症。然而，SRS排除了组织诊断，症状缓解的时间较慢。这项研究的目的是提供一套全新的工具，通过小于一英寸的切口靶向和消融肿瘤，从而实现开颅手术的微创性。因此，提供这种治疗的全套工具需要充分的可视化、精确的靶向（<1mm）和适形消融。提出的方法是将实时核磁共振引导的机器人辅助iHIFU植入与核磁共振热成像（MRTI）反馈相结合。该系统使用一个核磁共振兼容的机器人操作器，能够提供精确、可重复性和效率的导管，使这种治疗成为一种合理的辅助手段，而间质高强度超声允许高度精确的电子可配置治疗消融，能够在3D中精确控制体积（大小和形状），从很小（毫米）到中等（几厘米）的尺寸，而不会伤害附近与疾病无关的关键结构。所提出的方法的意义在于它

DESCRIPTION (provided by applicant): The goal of this project is to develop an integrated system for MRI-guided precise targeting and accurate ablation of brain tumors by interstitial high intensity focused ultrasound (iHIFU). Between 25-40% of patients with systemic cancer suffer the effect of brain metastases (BM). Treatment of BMs is often multidisciplinary involving open surgery, stereotactic radiosurgery (SRS), whole brain radiation, and/or chemotherapy. A subset of patients are candidates for open surgery and/or SRS. Open surgery via craniotomy in appropriate patients allows for tissue diagnosis, rapid relief of symptoms, and local disease control. The advantage of SRS is that it is non-invasive and avoids complications associated with craniotomy. SRS, however, precludes tissue diagnosis and time to symptom relief is slower. The purpose of the proposed research is to provide a complete new set of tools offering the benefits of craniotomy less invasively by targeting and ablating tumors through an incision less than one inch. The complete set of tools to deliver this therapy thus requires adequate visualization, precise targeting (<1mm), and conformal ablation. The proposed approach is to combine real-time MR-guided robot-assisted delivery of iHIFU with MR thermal imaging (MRTI) feedback. The system uses an MR-compatible robotic manipulator capable of delivering a cannula with the accuracy, reproducibility and efficiency needed to make this therapy a reasonable adjunct, while interstitial high-intensity ultrasound allows for highly precise electronically configurable therapeutic ablation with capability for exact volume (size and shape) control in 3D, from very small (mm) to moderate (several cm) size, without harming nearby critical structures not involved with disease. The significance of the proposed approach is that it offers a less invasive alternative to craniotomy, which provides the advantage over SRS of allowing for tissue diagnosis as well as immediate tumor ablation in difficult to reach regions of the human brain. The clinical focus of the proposed work is on brain metastases (BM), which are solid, well-demarcated from surrounding tissue, and amenable to MR-guided ablations. It is anticipated that successful development of this novel and highly controllable ablation system will eventually lead to future approaches to treat other types of tumors such as meningiomas. The aims of this project are to: 1) develop a MRI-compatible interstitial ultrasonic neuroablation instrument, 2) construct and evaluate an MRI-compatible manipulator for neuroablation instrument delivery and control, 3) develop and integrate computer-based 3D treatment planning and simulation tools, and 4) perform pre-clinical evaluations to confirm accuracy, optimize clinical workflow, and demonstrate successful ablative lesioning in clinically-relevant environment. Successful completion of this project will result in an experimental protocol in place with a veterinary hospital to use iHIFU as part of a treatment paradigm for canines with brain metastases, with human studies soon to follow.