Purpose: To develop and characterize a microwave imaging system that is sensitive for different tissue equivalent-phantoms of patient scale using a large field-of-view and to develop an image reconstruction algorithm based on holographic back-projection to reconstruct 2D-microwave images.
Methods: A microwave system with transmitter-receiver antennas was used to image tissue-equivalent phantoms. The variations of the microwave signal with phantom volume, density, size and water content were quantified. The microwave density dependence on different tissue equivalent phantom including bone, muscle, breast, and lung tissues was quantified. Microwave line projections were acquired by stepping the phantom in 1 mm increments in the microwave field perpendicular to the transmitter-receiver. 2D-microwave images were reconstructed using a holographic back-projection algorithm of the phantom objects in the field-of-view using the reflected and transmitted signals that were induced by the presence of the phantom. The microwave projections were corrected for interference and polarization effects before image reconstruction.
Results: 2D-microwave images for phantom inserts with different densities were reconstructed using holographic back-projection algorithm. The microwave signal had high sensitivity to different phantom inserts; and the minimal microwave intensity varied non-linearly with the density of the different inserts. The microwave intensity decreased non-linearly with increased phantom volume in the imaging view. The microwave intensity decreased linearly with increased volume of water in the imaging field-of-view. Spatial resolution of nearly 1.0 mm was obtained in locating the position of the different insets. High contrast resolution was obtained from the minimal microwave intensity that was measured with phantom inserts ranged from 0.4-0.8 mA for lung to adipose tissue-equivalent phantoms.
Conclusion: 2D-microwave images were reconstructed using a holographic back-projection algorithm for tissue-equivalent phantoms with different densities. Microwave imaging has high sensitivity to variations in volume, density and water content in the imaging field-of-view which has potential clinical application in medical imaging.
Not Applicable / None Entered.