Magnetic contrast agents for optical coherence tomography

Amy L. Oldenburg, Jillian R. Gunther, Farah Jean Jacques Toublan, Daniel L. Marks, Kenneth S Suslick, Stephen A. Boppart

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

Abstract

The magneto-mechanical effect is exploited as a means of producing background-free contrast in optical coherence tomography (OCT). Contrast agents consisting of iron-oxide particles and protein microspheres encapsulating colloidal iron-oxide have a sufficiently high magnetic susceptibility to be detected by modulation of a magnetic field gradient using a small solenoid coil. The externally-applied magnetic field mechanically rotates or translates these highly scattering contrast agents within the sample at the modulation frequency, which is subsequently detected as amplitude modulation of the OCT signal. Pairs of sequential axial scans (A-lines) are acquired with the magnetic field on and off, allowing one to build up a pair of images corresponding to the "on" and "off" states of the magnetic field. These image pairs are differenced to look for magnetic-specific effects, allowing one to distinguish the magnetic contrast agents from non-magnetic structures within the sample with a signal-to-background ratio of ∼23dB. This technique has the potential to be very powerful when coupled with targeting for in vivo molecular imaging. To evaluate this potential we demonstrate in vitro imaging of magnetically-labeled macrophage cells embedded in a 3D tissue phantom, in vitro tissue doped with contrast agents, and in vivo imaging of Xenopus laevis (African frog) tadpoles.

Original languageEnglish (US)
Title of host publicationSPIE Proceedings
Subtitle of host publicationCoherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine VIII
PublisherSPIE
Pages91-98
Number of pages8
Volume5316
DOIs
StatePublished - 2004

Keywords

  • Contrast agents
  • Magnetomechanics
  • Optical coherence tomography

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

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  • Cite this

    Oldenburg, A. L., Gunther, J. R., Toublan, F. J. J., Marks, D. L., Suslick, K. S., & Boppart, S. A. (2004). Magnetic contrast agents for optical coherence tomography. In SPIE Proceedings: Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine VIII (Vol. 5316, pp. 91-98). SPIE. https://doi.org/10.1117/12.529119