Coherence-based photoacoustic imaging of brachytherapy seeds implanted in a canine prostate

Muyinatu A. Lediju Bell, Danny Y. Song, Emad M. Boctor

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Visualization of individual brachytherapy seed locations assists with intraoperative updates to brachytherapy treatment plans. Photoacoustic imaging is advantageous when compared to current ultrasound imaging methods, due to its superior sensitivity to metal surrounded by tissue. However, photoacoustic images suffer from poor contrast with insufficient laser fluence. A short-lag spatial coherence (SLSC) beamformer was implemented to enhance these low-contrast photoacoustic signals. Photoacoustic imaging was performed with a transrectal ultrasound probe and an optical fiber surrounded by a light-diffusing sheath, placed at a distance of approximately 4-5 mm from the location of seeds implanted in an in vivo canine prostate. The average energy density through the tip of the sheath was varied from 8 to 167 mJ/cm 2. When compared to a fast Fourier transform (FFT)-based reconstruction method, the mean contrast and signal-to-noise ratios were improved by up to 22 dB and a factor of 4, respectively, with the SLSC beamformer (12% of the receive aperture elements were included in the short-lag sum). Image artifacts that were spatially coherent had spatial frequency spectra that were quadrantally symmetric about the origin, while the spatial frequency spectra of the seed signals possessed diagonal symmetry. These differences were utilized to reduce artifacts by 9-14 dB after applying a bandpass filter with diagonal symmetry. Results indicate that advanced methods, such as SLSC beamforming or frequency-based filters, hold promise for intraoperative localization of prostate brachytherapy seeds.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2014
Subtitle of host publicationUltrasonic Imaging and Tomography
PublisherSPIE
ISBN (Print)9780819498335
DOIs
StatePublished - Jan 1 2014
EventMedical Imaging 2014: Ultrasonic Imaging and Tomography - San Diego, CA, United States
Duration: Feb 18 2014Feb 20 2014

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume9040
ISSN (Print)1605-7422

Other

OtherMedical Imaging 2014: Ultrasonic Imaging and Tomography
CountryUnited States
CitySan Diego, CA
Period2/18/142/20/14

Keywords

  • FFT-based reconstruction
  • beamforming
  • contrast
  • frequency spectrum
  • ltering
  • optoacoustic imaging
  • photoacoustic imaging
  • signal-to-noise ratio
  • spatial coher-ence
  • ultrasound

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging

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  • Cite this

    Lediju Bell, M. A., Song, D. Y., & Boctor, E. M. (2014). Coherence-based photoacoustic imaging of brachytherapy seeds implanted in a canine prostate. In Medical Imaging 2014: Ultrasonic Imaging and Tomography [90400Q] (Progress in Biomedical Optics and Imaging - Proceedings of SPIE; Vol. 9040). SPIE. https://doi.org/10.1117/12.2043901