Deep non-contact photoacoustic initial pressure imaging

Reza, Parsin Haji; Bell, Kevan; Shi, Wei; Shapiro, James; Zemp, Roger J.

doi:10.1364/optica.5.000814

Cited by 58 publications

(44 citation statements)

References 38 publications

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“…Photoacoustic Remote Sensing (PARS™) is an emerging non-contact photoacoustic imaging technique 28,29 . PARS circumvents the limitations of conventional PA techniques by replacing the acoustic transducer with a continuous-wave detection laser 30,31 .…”

Section: Introductionmentioning

confidence: 99%

Non-contact reflection-mode optical absorption spectroscopy using photoacoustic remote sensing

Bell

Reza

2020

Opt. Lett.

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Histological visualizations are critical to clinical disease management and are fundamental to biological understanding. However, current approaches that rely on bright-field microscopy require extensive tissue preparation prior to imaging. These processes are labor intensive and contribute to delays in clinical feedback that can extend to two to three weeks for standard paraffin-embedded tissue preparation and interpretation. Here, we present a label-free reflectionmode imaging modality that reveals cellular-scale morphology by detecting intrinsic endogenous contrast. We accomplish this with the novel photoacoustic remote sensing (PARS) detection system that permits non-contact optical absorption contrast to be extracted from thick and opaque biological targets with optical resolution. PARS was examined both as a rapid assessment tool that is capable of managing large samples (>1 cm 2) in under 10 minutes, and as a high contrast imaging modality capable of extracting specific biological contrast to simulate conventional histological stains such as hematoxylin and eosin (H&E). The capabilities of the proposed method are demonstrated in a variety of human tissue preparations including formalin-fixed paraffinembedded tissue blocks and unstained slides sectioned from these blocks, including normal and neoplastic human brain, and breast epithelium involved with breast cancer. Similarly, PARS images of human skin prepared by frozen section clearly demonstrated basal cell carcinoma and normal human skin tissue. Finally, we imaged unprocessed murine kidney and achieved histologically relevant subcellular morphology in fresh tissue. This represents a vital step towards an effective real-time clinical microscope that overcomes the limitations of standard histopathologic tissue preparations and enables real-time pathology assessment.

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Section: Introductionmentioning

confidence: 99%

Non-contact reflection-mode optical absorption spectroscopy using photoacoustic remote sensing

Bell

Reza

2020

Opt. Lett.

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“…With an objective lens of 0.4 NA, the PARS system reported a lateral resolution of 2.7 µm, and an axial resolution of 43.3 µm. To further extend the applications of the PARS system, they developed deep PARS (dPARS) microscopy, which can achieve high resolution beyond the optical transport mean free path of the excitation wavelength [ 144 ]. The excitation beam was loosely focused on the sample to generate PA signals beyond the optical transport mean free path, whereas the probe beam was tightly focused on the tissue.…”

Section: All-optical Detection Reflection-mode Photoacoustic Micromentioning

confidence: 99%

A Review of Endogenous and Exogenous Contrast Agents Used in Photoacoustic Tomography with Different Sensing Configurations

Tsang

Wong

2020

Sensors

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Optical-based sensing approaches have long been an indispensable way to detect molecules in biological tissues for various biomedical research and applications. The advancement in optical microscopy is one of the main drivers for discoveries and innovations in both life science and biomedical imaging. However, the shallow imaging depth due to the use of ballistic photons fundamentally limits optical imaging approaches’ translational potential to a clinical setting. Photoacoustic (PA) tomography (PAT) is a rapidly growing hybrid imaging modality that is capable of acoustically detecting optical contrast. PAT uniquely enjoys high-resolution deep-tissue imaging owing to the utilization of diffused photons. The exploration of endogenous contrast agents and the development of exogenous contrast agents further improve the molecular specificity for PAT. PAT’s versatile design and non-invasive nature have proven its great potential as a biomedical imaging tool for a multitude of biomedical applications. In this review, representative endogenous and exogenous PA contrast agents will be introduced alongside common PAT system configurations, including the latest advances of all-optical acoustic sensing techniques.

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“…Since PARS only relies on initial pressure measurements, the data acquisition card is programmed to record for a short amount of time after each trigger, i.e., typically only for 320 ns, resulting in significantly less data to be transferred [9,10]. Since the bandwidth of the photodiode is 75 MHz, a sampling rate of 200 MS/s suffices, resulting in 64 element segments for each point acquisition; this sampling rate was used for all acquisitions presented.…”

Section: Mosaic Acquisitionmentioning

confidence: 99%

“…A recently reported imaging modality known as photoacoustic remote sensing (PARS) replaces the ultrasonic transducer with a continuous-wave detection laser [9][10][11][12]. PARS, unlike most reflection mode OR-PAM systems, provides high-quality optical resolution photoacoustic imaging in a noncontact setting.…”

Section: Introductionmentioning

confidence: 99%

“…The reported method is able to acquire a 6.45 × 5.8 mm 2 field of view in ninety seconds [19]. However, as PARS has demonstrated submicron resolution in a reflection-mode configuration, it necessitates a method that is capable of rapidly acquiring large field of views while maintaining a small step size and high resolution [10]. The reflection-mode configuration also enables the imaging of thick targets, and is more analogous to in situ imaging.…”

Section: Introductionmentioning

confidence: 99%

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Rapid High-Resolution Mosaic Acquisition for Photoacoustic Remote Sensing

Abbasi

Bell

Reza

2020

Sensors

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Mechanical stages are routinely used to scan large expanses of biological specimens in photoacoustic imaging. This is primarily due to the limited field of view (FOV) provided by optical scanning. However, stage scanning becomes impractical at higher scanning speeds, or potentially unfeasible with heavier samples. Also, the slow scan-rate of the stages makes high resolution scanning a time-consuming process. Some clinical applications such as microsurgery require submicron resolution in a reflection-mode configuration necessitating a method that can acquire large field of views with a small raster scanning step size. In this study, we describe a method that combines mechanical stages with optical scanning for the rapid acquisition of high-resolution large FOVs. Optical scanning is used to acquire small frames in a two-dimensional grid formed by the mechanical stages. These frames are captured with specific overlap for effective image registration. Using a step size of 200 nm, we demonstrate mosaics of carbon fiber networks with FOVs of 0.8 × 0.8 mm2 captured in under 70 s with 1.2 µm image resolution. Larger mosaics yielding an imaging area of 3 × 3 mm2 are also shown. The method is validated by imaging a 1 × 1 mm2 section of unstained histopathological human tissue.

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Deep non-contact photoacoustic initial pressure imaging

Cited by 58 publications

References 38 publications

Non-contact reflection-mode optical absorption spectroscopy using photoacoustic remote sensing

Non-contact reflection-mode optical absorption spectroscopy using photoacoustic remote sensing

A Review of Endogenous and Exogenous Contrast Agents Used in Photoacoustic Tomography with Different Sensing Configurations

Rapid High-Resolution Mosaic Acquisition for Photoacoustic Remote Sensing

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