Virtual and Augmented Reality Guidance for Hepatic RFA

Principal Investigator: Henry Fuchs
Funding Agency: Natonal Cancer Institute 
Agency Number: 1-R01-CA101186-01A2

Abstract
Our goal is to improve the needle guidance and placement of percutaneous radio-frequency ablation (RFA) of hepatic tumors, in order to increase the accuracy of and thereby reduce incidence of complications from this increasingly popular treatment modality. Inaccurate needle placement is a significant problem, likely contributing to a substantial portion of recurrence lesions, 90% of which are located at the periphery of the original tumor. Building on our recent advances in guidance for ultrasound-based needle biopsy of the breast, we propose to develop a system in which all the components (ultrasound transducer, ultrasound image, the RFA needle, the relevant patient anatomy) are viewed together in their precise 3D conformation. We hypothesize that such a visualization, seen by the physician near (or indeed, within) the patient's body, enables not only easier comprehension of complex 3D geometric and anatomic structures, but facilitates more natural hand-eye coordination in the manipulation of the transducer and the RFA probe. We propose a series of design, build, test, and evaluate methods, including: 1) design and implementation of a transportable, PC-based system with the four most promising displays (video see-through head-mounted display, stereo projection, stereo direct-view, and conventional 2D flat panel); 2) a controlled pilot study of each alternative with commercial liver phantoms by the chief interventional radiologist (IR), M. Mauro; 3) selection and optimization of the top two modalities; 4) a controlled phantom study of the top two modalities by a group of board-certified interventional radiologists; 5) performance evaluation by a separate team of two specialists; 6) a small clinical trial with human patients by the chief IR using the most effective system; 7) evaluation of results, and 8) a cross-over training study to measure learning rates of medical students and residents using our system. Potential benefits include reduced recurrence due to missed cancerous cells at tumor margins and reduced complications due to needle misplacement near sensitive healthy structures. In the long-term, we hope to enable treatment for cases that today are intractable with RFA due to 1) such large tumor size that an overwhelming number of precise placements are necessary or 2) needle placement so close to healthy structures that colateral damage from even small misplacement may cause unacceptable complications. With RFA becoming, along with surgical excision, a mainline treatment for localized cancerous tumors throughout the body, the proposed improved guidance techniques may eventually prove beneficial for many thousands of patients with localized tumors.