title: Near-field thermoacoustic tomography of small animals.
abstract: Near-field radiofrequency thermoacoustic (NRT) tomography is a new imaging method that was developed to mitigate limitations of conventional thermoacoustic imaging approaches, related to hard compromises between signal strength and spatial resolution. By utilizing ultrahigh-energy electromagnetic impulses at ∼20 ns duration along with improved energy absorption coupling in the near-field, this method can deliver high-resolution images without compromising signal to noise ratio. NRT is a promising modality, offering cost-effectiveness and ease of implementation and it can be conveniently scaled to image small animals and humans. However, several of the performance metrics of the method are not yet documented. In this paper, we characterize the expected imaging performance via numerical simulations based on a finite-integration time-domain (FITD) technique and experiments using tissue mimicking phantoms and different biological samples. Furthermore, we show for the first time whole-body tomographic imaging results from mice, revealing clear anatomical details along with highly dissipative inclusions introduced for control. The best spatial resolution achieved for those experiments was 150 µm.
authors.affiliation: Institute for Biological and Medical Imaging (IBMI), Technische Universität München and Helmholtz Zentrum München, Ingolstaedter Landstrasse 1, D-85764 Neuherberg, Germany. stephan.kellnberger@tum.de
authors.forename: Stephan
authors.initials: S
authors.lastname: Kellnberger
authors.forename: Amir
authors.initials: A
authors.lastname: Hajiaboli
authors.forename: Daniel
authors.initials: D
authors.lastname: Razansky
authors.forename: Vasilis
authors.initials: V
authors.lastname: Ntziachristos
mesh_terms: D000162:Acoustics; D000818:Animals; D006358:Hot Temperature; D051379:Mice; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D013997:Time Factors; D014054:Tomography / Q000295:instrumentation / Q000379:methods*