Reflection-mode submicron-resolution in vivo photoacoustic microscopy

Chi Zhang; Konstantin I. Maslov; Song Hu; Lihong V. Wang; Ruimin Chen; Qifa Zhou; K. Kirk Shung

doi:10.1117/1.JBO.17.2.020501

23 February 2012 Reflection-mode submicron-resolution in vivo photoacoustic microscopy

Chi Zhang, Konstantin I. Maslov, Song Hu, Lihong V. Wang, Ruimin Chen, Qifa Zhou, K. Kirk Shung

Author Affiliations +

Journal of Biomedical Optics, Vol. 17, Issue 2, 020501 (February 2012). https://doi.org/10.1117/1.JBO.17.2.020501

Abstract

Submicron-resolution photoacoustic microscopy (PAM) currently exists only in transmission mode, due to the technical difficulties of combining high numerical-aperture (NA) optical illumination with high NA acoustic detection. The lateral resolution of reflection-mode PAM has not reached <2 μm in the visible light range. Here we develop the first reflection-mode submicron-resolution PAM system with a new compact design. By using a parabolic mirror to focus and reflect the photoacoustic waves, sufficient signals were collected for good sensitivity without distorting the optical focusing. By imaging nanospheres and a resolution test chart, the lateral resolution was measured to be ∼ 0.5 μm with an optical wavelength of 532 nm, an optical NA of 0.63. The axial resolution was measured at 15 μm. Here the axial resolution was measured by a different experiment with the lateral resolution measurement. But we didn't describe the details of axial resolution measurement due to space limit. The maximum penetration was measured at ∼ 0.42 mm in optical-scattering soft tissue. As a comparison, both the submicron-resolution PAM and a 2.4 μm-resolution PAM were used to image a mouse ear in vivo with the same optical wavelength and similar pulse energy. Capillaries were resolved better by the submicron-resolution PAM. Therefore, the submicron-resolution PAM is suitable for in vivo high-resolution imaging, or even subcellular imaging, of optical absorption.

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Chi Zhang, Konstantin I. Maslov, Song Hu, Lihong V. Wang, Ruimin Chen, Qifa Zhou, and K. Kirk Shung "Reflection-mode submicron-resolution in vivo photoacoustic microscopy," Journal of Biomedical Optics 17(2), 020501 (23 February 2012). https://doi.org/10.1117/1.JBO.17.2.020501

Published: 23 February 2012

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