Phantom design for tracked ultrasound-based surgical navigation systems

For pediatric oncology patients, radical tumor removal is crucial. Surgical navigation using tracked ultrasound may improve radical removal rates in pediatric surgery, based on positive clinical outcomes in adult tumor surgery. Prior to implementation, such surgical navigation systems must be validated under controlled conditions. This requires surgical phantoms with a speed of sound comparable to human tissue to enable accurate tracked ultrasound imaging and which include anatomical structures with ultrasound and Computed Tomography (CT) contrast. However, scarcity exists of such phantoms. This study presents a method for developing anatomical phantoms tailored for evaluating tracked ultrasound-based surgical navigation systems. • A gelatin-vinegar matrix was selected for its speed of sound, durability and stability. • Tumors were developed using polyvinyl alcohol mixed with glass microspheres and barium sulfate to achieve ultrasound and CT contrast. The speed of sound of the gelatin-vinegar matrix was investigated by depth measurements on both ultrasound and CT imaging. The resulting phantoms are durable, low-cost (<50$ p/phantom) and have a speed of sound approximating human tissue to enable tracked ultrasound. Moreover, the phantom materials are widely available, and the phantoms are easy to make. With this protocol, we offer a method for preclinical validation of ultrasound-based surgical navigation systems.