Development of a Computational Treatment Planning System for Radiofrequency Ablation of Vertebral Metastases

Abstract

Introduction: Vertebral metastases affect around 61,000 Americans annually. The presence of vertebral metastases may lead to skeletal related events which can include pain, fracture, and neurologic compromise, all of which can negatively impact a patient’s mobility and quality of life. Radiofrequency (RF) ablation is a minimally invasive thermal therapy used to palliatively treat vertebral metastases. Current treatment practices incorporate little to no treatment planning and utilize two-dimensional imaging to localize the vertebra of interest. This may lead to inadequate treatment dose or delivering dose to healthy tissues. To address the need for better planning and delivery of RF ablation in spine procedures, this work aims to design and develop a computational treatment planning system (TPS) capable of generating patient specific treatment plans. The system was validated using functionality and usability testing. Methods: System requirements were determined based on input from clinicians and researchers. Using these requirements, a TPS that could interact with an external dose engine was developed using the open source platform, 3D Slicer. Patient imaging was obtained to perform functionality testing of the designed TPS. Testing was performed using a simplified prescribed dose function. The calculation of damage volumes was done on voxel-based meshes and compared to a ground truth. Usability testing was also performed with data captured from questionnaires given to clinicians after interacting with the system. Results: 14 patient CT scans were used to generate RF ablation treatment plans. In all cases the TPS was able to perform all necessary functionality. The voxel-based meshes produced thermal damage volumes larger than the ground truth. Usability testing indicated that clinicians were supportive of this TPS being adopted for RF ablation of vertebral metastases. The most likely clinical uptake for this system would come through radiation oncology, with treatment plans provided to orthopaedic surgeons and interventional radiologists. Conclusion: A computational treatment planning system could be a feasible and beneficial addition to the clinical workflow for RF ablation of vertebral metastases.