title: Microwave-induced thermoacoustic tomography: reconstruction by synthetic aperture.
abstract: We have applied the synthetic-aperture method to linear-scanning microwave-induced thermoacoustic tomography in biological tissues. A nonfocused ultrasonic transducer was used to receive thermoacoustic signals, to which the delay-and-sum algorithm was applied for image reconstruction. We greatly improved the lateral resolution of images and acquired a clear view of the circular boundaries of buried cylindrical objects, which could not be obtained in conventional linear-scanning microwave-induced thermoacoustic tomography based on focused transducers. Two microwave sources, which had frequencies of 9 and 3 GHz, respectively, were used in the experiments for comparison. The 3 GHz system had a much larger imaging depth but a lower signal-noise ratio than the 9 GHz system in near-surface imaging.
authors.affiliation: Optical Imaging Laboratory, Biomedical Engineering Program, Texas A&M University, College Station 77843-3120, USA.
authors.forename: D
authors.initials: D
authors.lastname: Feng
authors.forename: Y
authors.initials: Y
authors.lastname: Xu
authors.forename: G
authors.initials: G
authors.lastname: Ku
authors.forename: L V
authors.initials: LV
authors.lastname: Wang
mesh_terms: D000162:Acoustics; D000465:Algorithms; D055592:Biophysical Phenomena; D001703:Biophysics; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008872:Microwaves; D011871:Radiology / Q000379:methods*; D013696:Temperature