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Updated: May 28, 2025
Controllable Nucleation of Cavitation from Plasmonic Gold Nanoparticles for Enhancing High Intensity Focused Ultrasound Applications
Published on: October 5, 2018
A high magnetic resonance imaging (MRI) contrast agar/silica-based phantom for evaluating focused ultrasound (FUS)
Antria Filippou1, Nikolas Evripidou1, Christakis Damianou1
1Cyprus University of Technology, Department of Electrical Engineering, Computer Engineering, and Informatics, Limassol, Cyprus.
Purpose:
Thermal ablation therapies require tissue mimicking phantoms for evaluating novel systems. Herein, an agar phantom exhibiting high magnetic resonance imaging (MRI) contrast to noise ratio (CNR) was developed for testing focused ultrasound (FUS) protocols.
Methods:
Four agar based phantoms (6 % w/v) were fabricated with varied silica concentrations (0, 2, 4, or 6 % w/v) and subjected to FUS inside a 3 T MRI. T2-Weighted Fast Spin Echo (T2-W FSE) images were acquired after sonications to assess the effect of varied silica on CNR of inflicted lesions. The highest CNR phantom was sonicated and its proton resonance frequency (PRF) coefficient, thermal dose denaturation threshold and ability to sustain good lesion CNR 0-44 min post exposures were assessed.
Results:
T2-W median lesion CNR between 1.5-453.5 was observed, exponentially increasing with increased silica concentration. High CNR was achieved with 4 % w/v silica, with the PRF coefficient of the phantom calculated at -0.00954 ppm/°C. The thermal dose denaturation threshold was revealed at 2 × 106 CEM43°C by comparing thermal dose maps with T2-W FSE lesion hyperenhancement. Progressive lesion CNR loss was observed, with CNR lost 28 min after sonications.
Conclusions:
The proposed phantom possesses excellent T2-W contrast of inflicted lesions while exhibiting a tissue like PRF coefficient and can thus constitute an inexpensive reusable tool for validating FUS systems and protocols.
