Building Ultrasound Phantoms with Modified Polyvinyl Chloride: A Comparison of Needle Insertion Forces and Sonographic Appearance with Commercial and Traditional Simulation Materials

Introduction Training using ultrasound phantoms allows for safe introduction to clinical skills and is associated with improved in-hospital performance. Many materials have been used to simulate human tissue in phantoms including commercial manikins, agar, gelatin, and Ballistics Gel; however, phantom tissues could be improved to provide higher-fidelity ultrasound images or tactile sensation. This article describes a novel phantom tissue mixture of a modified polyvinyl chloride (PVC) polymer, mineral oil, and chalk powder and evaluates needle cutting and ultrasonic properties of the modified PVC polymer mixture compared with a variety of phantom tissues. Methods The first experiment measured axial needle forces of a needle insertion into nine phantom materials, including three formulations of modified PVC. The second experiment used a pairwise comparison survey of ultrasound images to determine the perceived realism of phantom ultrasound images. Results It was found that the materials of Ballistics Gel and one of the PVC mixtures provide stiff force feedback similar to cadaver tissue. Other phantom materials including agar and gelatin provide very weak unrealistic force feedback. The survey results showed the PVC mixtures being viewed as the most realistic by the survey participants, whereas agar and Ballistics Gel were seen as the least realistic. Conclusions The realism in cutting force and ultrasound visualization was determined for a variety of phantom materials. Novel modified PVC polymer has great potential for use in ultrasound phantoms because of its realistic ultrasound imaging and modifiable stiffness. This customizability allows for easy creation of multilayer tissue phantoms.