Characterization of soft tissue-mimicking materials for ultrasound training phantoms

Tissue-mimicking materials are essential for developing realistic ultrasound phantoms in medical training and device calibration. This study systematically evaluates the acoustic and physical properties of 15 materials, including gelatin-based formulations, synthetic gels, and rubbers, to assess their suitability for simulating human soft tissues. The investigation focused on ultrasound propagation speed, attenuation coefficients, and temporal stability, with measurements conducted under controlled conditions to ensure consistency. Results revealed that organic gelatins exhibited propagation speeds (1508-1626 m/s) and attenuation coefficients (0.21-1.10 dB/cm) closely aligned with soft tissue benchmarks (1540 m/s and 0.54 dB/cm MHz, respectively), with minimal variations (<5%) over 15 days. However, their susceptibility to dehydration and mold growth necessitates protective measures. Synthetic gels, such as ballistic gel and PVC-Plastisol, demonstrated superior long-term stability but required more complex fabrication processes. Rubbers, while durable, exhibited acoustic properties that deviated significantly from tissue standards, limiting their utility. The study quantitatively highlights trade-offs between material categories: gelatins offer cost-effectiveness and acoustic fidelity for short-term use, whereas synthetic gels provide durability for repeated applications. These findings provide a comprehensive framework for selecting materials tailored to specific phantom requirements, balancing acoustic accuracy, stability, and manufacturability. The work advances the development of high-fidelity, cost-effective phantoms, with implications for improving ultrasound training and diagnostic tool validation. Future research should explore hybrid materials and extended stability assessments to further optimize phantom performance.