Slow-sound photoacoustic microscopy

Zhang, Chi; Zhou, Yong; Li, Chiye; Wang, Lihong V.

doi:10.1063/1.4803444

Cited by 26 publications

(19 citation statements)

References 16 publications

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“…Taking the FWHM of the PA amplitude in the axial direction, we estimated the axial resolution as 59 μm (Fig. 3(b)), which is close to the theoretical value (0.88v s /Δf = 53 μm, where v s is the sound speed in soft tissue, and Δf is the frequency bandwidth of the transducer) [29]. …”

supporting

confidence: 76%

Handheld photoacoustic microscopy to detect melanoma depth in vivo

et al. 2014

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We developed handheld photoacoustic microscopy (PAM) to detect melanoma and determine tumor depth in nude mice in vivo. Compared to our previous PAM system for melanoma imaging, a new light delivery mechanism is introduced to improve light penetration. We show that melanomas with 4.1 mm and 3.7 mm thicknesses can be successfully detected in phantom and in in vivo experiments, respectively. With its deep melanoma imaging ability and handheld design, this system can be tested for clinical melanoma diagnosis, prognosis, and surgical planning for patients at the bedside.

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confidence: 76%

Handheld photoacoustic microscopy to detect melanoma depth in vivo

et al. 2014

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“…Besides its improved resolutions, GR-PAM also enables measurement of the absolute absorption coefficient without calibration of the local optical fluence. We notice that acoustic-scale axial resolution has recently been pushed to several microns using either deconvolution or a high frequency ultrasonic transducer [18, 19]. However, the optical sectioning capability provided by GR-PAM still shows salient advantages, such as not requiring high-frequency transducers or a model-based algorithm, and it can also measure absolute absorption coefficients without fluence calibration.…”

Section: Discussionmentioning

confidence: 99%

“…Other axial resolution quantification methods might give a finer acoustic axial resolution [17]. Higher frequency ultrasonic transducers and deconvolution algorithm have been utilized to achieve higher acoustically defined axial resolution at the cost of signal-to-noise ratio [18, 19]. Nevertheless, GR-PAM provides a unique approach to achieve optically defined axial resolution, whose novel imaging and sensing capabilities are demonstrated in the following two experiments.…”

Section: Measurement Of Lateral and Axial Resolutionsmentioning

confidence: 99%

Grueneisen Relaxation Photoacoustic Microscopy

2014

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The temperature-dependent property of the Grueneisen parameter has been employed in photoacoustic imaging mainly to measure tissue temperature. Here we explore this property using a different approach and develop Grueneisen-relaxation photoacoustic microscopy (GR-PAM), a technique that images non-radiative absorption with confocal optical resolution. GR-PAM sequentially delivers two identical laser pulses with a micro-second-scale time delay. The first laser pulse generates a photoacoustic signal and thermally tags the in-focus absorbers. Owing to the temperature dependence of the Grueneisen parameter, when the second laser pulse excites the tagged absorbers within the thermal relaxation time, a photoacoustic signal stronger than the first one is produced. GR-PAM detects the amplitude difference between the two co-located photoacoustic signals, confocally imaging the non-radiative absorption. We greatly improved axial resolution from 45 µm to 2.3 µm and at the same time slightly improved lateral resolution from 0.63 µm to 0.41 µm. In addition, the optical sectioning capability facilitates the measurement of the absolute absorption coefficient without fluence calibration.

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“…9,10 Reducing the SOS can also improve the axial resolution but often necessitates disturbing the original biological environment. 11 In addition, a multiview OR-PAM, which images the sample from multiple view angles and then reconstructs the image with a multiview deconvolution method, has been proposed to realize three-dimensional (3-D) optical resolution. 12 However, it was demonstrated only in (semi-)transparent samples, such as zebra fish.…”

Section: Introductionmentioning

confidence: 99%

Grueneisen relaxation photoacoustic microscopyin vivo

Shi

Hai

et al. 2016

J. Biomed. Opt

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Abstract. Grueneisen relaxation photoacoustic microscopy (GR-PAM) can achieve optically defined axial resolution, but it has been limited to ex vivo demonstrations so far. Here, we present the first in vivo image of a mouse brain acquired with GR-PAM. To induce the GR effect, an intensity-modulated continuous-wave laser was employed to heat absorbing objects. In phantom experiments, an axial resolution of 12.5 μm was achieved, which is sixfold better than the value achieved by conventional optical-resolution PAM. This axial-resolution improvement was further demonstrated by imaging a mouse brain in vivo, where significantly narrower axial profiles of blood vessels were observed. The in vivo demonstration of GR-PAM shows the potential of this modality for label-free and high-resolution anatomical and functional imaging of biological tissues.

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Slow-sound photoacoustic microscopy

Cited by 26 publications

References 16 publications

Handheld photoacoustic microscopy to detect melanoma depth in vivo

Handheld photoacoustic microscopy to detect melanoma depth in vivo

Grueneisen Relaxation Photoacoustic Microscopy

Grueneisen relaxation photoacoustic microscopyin vivo

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