Effect of Injection Parameters on the MRI and Dielectric Properties of Silicone

Phantoms with tissue-mimicking properties play a crucial role in the calibration or tuning of medical imaging modalities, specifically Magnetic Resonance Imaging (MRI). Among these phantoms, silicone-based ones are widely used due to their long-term stability in MRI. Most of these phantoms were manufactured using traditional pour mold techniques, which often result in the presence of air bubbles that severely degrade the quality of MRI data. This thesis proposes the use of extrusion techniques to fabricate silicone phantoms and explores the effects of extrusion parameters, including plunger speed and nozzle diameter, on void content, T1 and T2 relaxation times, and dielectric properties. A custom double-syringe silicone extrusion apparatus was developed to prepare silicone samples. The void content, relaxometry, and dielectric properties of extruded samples were measured and compared with traditional poured samples. This study demonstrates the potential of extrusion techniques for manufacturing silicone phantoms with reduced air bubble formation and provides valuable insights into the relationship between extrusion parameters and phantom properties.<p></p>