Method for Developing Tissue-mimicking Ultrasound Imaging Phantoms of Organs using Polyvinyl Alcohol and 3-D Printed...

Medical imaging has advanced significantly, driving the need for realistic phantoms to enhance diagnosis, training and system calibration. However, existing homemade phantoms have limited lifespans and suboptimal tissue-mimicking properties, while commercial phantoms are often costly and inaccessible to many researchers. This study aims to fabricate polyvinyl alcohol cryogel phantoms replicating rabbit liver and human thyroid tissues using 3-D printing and silicone moulding techniques.

Polyvinyl alcohol cryogel phantoms were fabricated using multiple freeze-thaw cycles to achieve the desired acoustic and mechanical properties. Silicone moulding and 3-D printing enable anatomically accurate moulds for precise tissue replication. The phantoms' acoustic and mechanical properties, including speed of sound, acoustic impedance, Young's modulus, shear modulus and density, were evaluated.

The fabricated phantoms exhibited acoustic (3 MHz) and mechanical properties closely related to those of actual rabbit liver and human thyroid tissues, including speed of sound (1528±6 m/s and 1531±6 m/s), acoustic impedance (1.60±0.01 Mrayl and 1.64±0.02 Mrayl), Young's modulus (129.02±3.43 kPa and 131.48±5.78 kPa), shear modulus (43.01±3.43 kPa and 43.83±2.39 kPa) and density (1050 kg/m³ and 1070 kg/m³), respectively. The phantoms also replicated ultrasound speckle patterns, enhancing their realism for imaging applications.

The polyvinyl alcohol cryogel phantoms closely resemble the acoustic and mechanical properties of rabbit liver and human thyroid tissues. Their cost-effective fabrication and accurate tissue replication make them ideal for ultrasound imaging research, training, education and calibration.