Photoacoustic Imaging

Ultrasonic Imaging

Multimodal Imaging

2012 Lab Poster

2011 Lab Poster


Currently BUIL is dedicated to developing novel bio-photonic and ultrasonic imaging techniques for structural, functional, and molecular imaging, including photoacoustic imaging, ultrasonic imaging, and the synergy of the two imaging technologies (i.e., multimodal imaging).

It is anticipated that the techniques we develop may advance biomedical science and aid in clinical diagnosis, typically for studying and diagnosing a number of diseases where microvascular changes impact health, including cancer, dermatological disorders, cardiovascular disease, and peripheral microvascular complications in diabetics.

  • Photoacoustic Imaging - 光聲影像 (see wikipedia)

  • A major challenge to in vivo optical imaging techniques is the highly scattering nature of light in biological tissue. As a result, its spatial resolution significantly decreases with increasing imaging depth (typically in the region over 1 mm). Photoacoustic imaging is an emerging hybrid bio-photonic imaging technique that detects absorbed photons ultrasonically and locally through the photoacoustic effect. The marriage of ultrasound and light in this technique overcomes the resolution drawback of pure optical imaging due to overwhelming light scattering in biological tissues, and possesses the merit and most compelling features of both optics and ultrasound—namely, high optical absorption contrast and sub-millimeter ultrasound resolution—up to an imaging depth of centimeters.

    Photo-acoustic imaging has been applied to vasculature structural imaging, breast tumor detection, oxygenation monitoring in single blood vessels (important in tumor growth), and molecular imaging of targeting nanoparticles (personalized medicine) etc. Photoacoustic signals are induced as a result of transient thermo-elastic expansion when biological tissues absorb the pulsed laser energy. These signals are then detected by acoustic transducers and reconstructed to form images representative of optical absorption distribution. Based on differences in optical molar extinction spectra of absorbers, multiple-wavelength/spectroscopic photo-acoustic imaging techniques offer separation of different absorber contributions, which enables functional imaging with endogenous hemoglobin contrast and molecular imaging with exogenous molecular contrast. Photoacoustic imaging technology may provide a new paradigm for functional imaging, molecular imaging, and gene expression imaging based on optical absorption contrast.

    In BUIL, we are now working on developing all kinds of photoacoustic imaging systems ranging from small-scale (cell-level), mid-scale (small-animal level)  to large-scale (human-level) imaging, and exploring the related applications:

    (1) System development of photoacoustic microscopy (PAM)
    (2) Neuro-vascular imaging with functional PAM
    (3) Cancer-related calcification imaging
    (4) Improved quantitative functional and molecular imaging
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  • Ultrasonic Imaging - 超音波影像 (see wikipedia)

  • Ultrasound is sound with frequencies high than the audible range, i.e., > 20 KHz. Typically, frequencies ranging from 0.1 MHz to 50 MHz are used in biomedical applications. For diagnostic purpose, ultrasound is transmitted to human bodies or testing objects, interrogating with tissues, and then received by ultrasonic transducers. The received signals are then decoded into images regarding anatomic structures and functional information. Advantages of diagnostic ultrasound are non-invasive, real time, portable, and offering Doppler flow imaging. Wide-spectrum applications of ultrasound imaging are available (see wikipedia). In BUIL, we are looking for breakthrough in ultra-high frame rate array imaging/beamformation, image guidance of high-intensity focused ultrasound (HIFU) thermal ablation, and calcification imaging.

    Currently, we are working on:

    (1) Improved ultra-high frame-rate imaging techniques
    (2) Parametric imaging for monitoring HIFU- and laser-based thermal ablation and drug delivery.
    (3) Compressed sensing high-frame rate ultrasound imaging
    (4) Enhanced cancer-related calcification imaging
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  • Multimodal Imaging

  • Photoacoustic imaging (functional and vascular information) may complement ultrasound imaging (structural and flow information) to provide more diagnostic information (multi-modality imaging), e.g., detection of very small vessels as well as those with slow flow velocities.

    We have been working on:

    (1) Dual modal imaging for dianosis and monitoring tendon injury and therapeutic effect
    (2) Imaging local drug delivery by focused ultrasound
    (3) Imaging of plasmonics based photothermal therapy
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