title: Imaging of small nanoparticle-containing objects by finite-element-based photoacoustic tomography.
abstract: We present semiquantitative photoacoustic images of small nanoparticle-containing objects having a wide range of contrast levels relative to the background. The images are obtained by a finite-element reconstruction algorithm that is based on the Helmholtz-like photoacoustic wave equation in the frequency domain. Our reconstruction approach is an iterative Newton method coupled with combined Marquardt and Tikhonov regularizations that can extract the spatial distribution of relative optical absorption property in heterogeneous media. We demonstrate experimental images in single- and multiple-object configurations with a circular scanning photoacoustic tomographic system. The results obtained show that millimeter-size nanoparticle-containing objects can be clearly detected in terms of position, size, and relative optical properties.
authors.affiliation: Department of Biomedical Engineering, University of Florida, Gainesville 32611, USA.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Yuan
authors.forename: Changfeng
authors.initials: C
authors.lastname: Wu
authors.forename: Hongzhi
authors.initials: H
authors.lastname: Zhao
authors.forename: Huabei
authors.initials: H
authors.lastname: Jiang
mesh_terms: D000162:Acoustics; D000465:Algorithms; D003198:Computer Simulation; D020342:Finite Element Analysis; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D016247:Information Storage and Retrieval / Q000379:methods; D008954:Models, Biological; D049329:Nanostructures / Q000648:ultrastructure*; D010316:Particle Size; D010363:Pattern Recognition, Automated / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D041622:Tomography, Optical / Q000379:methods*