Author: Imad M. Ali, Nesreen Alsbou, Sakeeneh Majeed 👨🔬
Affiliation: University of Central Oklahoma, University of Oklahoma Health Sciences Center 🌍
Purpose: to design and assess a microwave imaging system equipped with multiple antennas for generating high-resolution 3D images of phantom models that simulate abdominal, thoracic, and brain tissues.
Methods: A microwave imaging scanner was developed with multiple antennas arranged in a ring around the phantom objects. This configuration allowed for the acquisition of both 2D- and 3D-microwave images of phantom models representing various anatomical regions with different tissue densities. The phantoms were made of materials mimicking soft tissue, which enabled the evaluation of the microwave system's sensitivity, linearity, and uniformity. This allowed for the creation of axial 2D-microwave images. The phantoms were then moved in 2mm increments to construct 3D-images. The performance of the microwave images, including linearity, uniformity, spatial resolution, and contrast resolution, was assessed in relation to the number of antennas, microwave frequency, and the antenna positioning relative to the phantoms.
Results: The microwave scanner developed in this work produced successfully 2D- and 3D-microwave images of various phantom models. The images displayed clear contrast resolution across different tissue types including lung, breast, adipose tissue, muscle, liver, and bone. The image uniformity was evaluated using a homogeneous water phantom. Image quality was affected by factors including microwave frequency, antenna count, and antenna placement relative to the phantoms. Higher frequencies and an increased number of antennas improved spatial resolution. However, image quality declined as the distance between the antennas and the phantom increased due to air attenuation. The microwave response showed a linear decrease with increasing water volume within the imaging field of view.
Conclusion: A microwave scanner was designed, and its performance, as well as image quality, were thoroughly evaluated using different soft-tissue equivalent phantoms. While microwave imaging is still in the early stages of development, it shows promising potential for clinical applications in diagnostic imaging and radiation therapy.