Towards a Low-Cost and Portable Photoacoustic Microscope for Point-of-Care and Wearable Applications

Dangi, Ajay; Agrawal, Sumit; Datta, Gaurav; Srinivasan, Visweshwar; Kothapalli, Sri Rajasekhar

doi:10.1109/jsen.2019.2935684

Cited by 26 publications

(20 citation statements)

References 41 publications

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“…There have been several promising progress in science and clinics [40]- [44]. The investigators envision to develop an implantable and/or portable photoacoustic sensor for instantaneous/continuous monitoring of patients with various disorders [45]- [48]. An ultra-compact development of ultrasound receive module would facilitate the translation of the photoacoustic imaging investigations into practice.…”

Section: Discussionmentioning

confidence: 99%

Efficient Parallel-Beamforming Based on Shared FIFO for Ultra-Compact Ultrasound Imaging Systems

Kang¹,

Kim²,

Yoon³

et al. 2020

IEEE Access

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The realization of a parallel-beamforming (pBF) method in ultra-compact ultrasound imaging systems is challenging to achieve uncompromised beamforming accuracy in limited hardware and power resources. In this paper, we present a new hardware-and power-efficient pBF method that utilizes a shared first-in-first-out block on a post-fractional delay filtering architecture (pBF-sFIFO). For an analog-to-digital conversion (ADC) rate given, the proposed pBF-sFIFO method yielded beamforming accuracy comparable to that by an unconstrained pBF (pBF-CON) method, with up to 15% less power consumption. Otherwise, a conventional time-sharing pBF method (pBF-TS) was more vulnerable to aliasing artifacts. Even though increasing ADC rate in the pBF-TS method could recover the beamforming accuracy, exponential need in power consumption was inevitable. Therefore, the pBF-sFIFO method would be an effective solution to enable advanced imaging features in ultra-compact ultrasound imaging systems. INDEX TERMS Hardware complexity, parallel-beamforming, point-of-care, power consumption, ultracompact ultrasound imaging systems.

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Section: Discussionmentioning

confidence: 99%

Efficient Parallel-Beamforming Based on Shared FIFO for Ultra-Compact Ultrasound Imaging Systems

Kang¹,

Kim²,

Yoon³

et al. 2020

IEEE Access

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“…PAI based on PMN-PT pMUTs has been demonstrated. For example, Dangi et al reported a 2.5 mm diameter ring pMUT based on single-crystal PMN-PT with an optical fiber integrated for portable and wearable photoacoustic microscopy applications [ 103 ]. The fabricated pMUT had a center frequency of 17.25 MHz with a −6 dB bandwidth of 45%.…”

Section: Pmuts and Their Endoscopic Pai Applicationsmentioning

confidence: 99%

“… Optical image of the photoacoustic transducer device ( a ) and the front view of the pMUT surface ( b ) (Reproduced with permission from IEEE [ 103 ]). …”

Section: Figurementioning

confidence: 99%

MEMS Ultrasound Transducers for Endoscopic Photoacoustic Imaging Applications

Wang

Yang

et al. 2020

Micromachines

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Photoacoustic imaging (PAI) is drawing extensive attention and gaining rapid development as an emerging biomedical imaging technology because of its high spatial resolution, large imaging depth, and rich optical contrast. PAI has great potential applications in endoscopy, but the progress of endoscopic PAI was hindered by the challenges of manufacturing and assembling miniature imaging components. Over the last decade, microelectromechanical systems (MEMS) technology has greatly facilitated the development of photoacoustic endoscopes and extended the realm of applicability of the PAI. As the key component of photoacoustic endoscopes, micromachined ultrasound transducers (MUTs), including piezoelectric MUTs (pMUTs) and capacitive MUTs (cMUTs), have been developed and explored for endoscopic PAI applications. In this article, the recent progress of pMUTs (thickness extension mode and flexural vibration mode) and cMUTs are reviewed and discussed with their applications in endoscopic PAI. Current PAI endoscopes based on pMUTs and cMUTs are also introduced and compared. Finally, the remaining challenges and future directions of MEMS ultrasound transducers for endoscopic PAI applications are given.

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“…However, to translate PAI technology to POC clinical applications and to resource-limited settings, a significant reduction in both cost and size is required. To address this challenge, several cost-effective alternatives for both the optical excitation [ 32 , 33 , 34 , 35 ] and the ultrasound detection [ 36 , 37 , 38 , 39 ] components have been explored, including for wearable applications [ 40 , 41 ].…”

Section: Introductionmentioning

confidence: 99%

Photoacoustic Imaging of Human Vasculature Using LED versus Laser Illumination: A Comparison Study on Tissue Phantoms and In Vivo Humans

Agrawal

Singh²,

Johnstonbaugh

et al. 2021

Sensors

Self Cite

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Vascular diseases are becoming an epidemic with an increasing aging population and increases in obesity and type II diabetes. Point-of-care (POC) diagnosis and monitoring of vascular diseases is an unmet medical need. Photoacoustic imaging (PAI) provides label-free multiparametric information of deep vasculature based on strong absorption of light photons by hemoglobin molecules. However, conventional PAI systems use bulky nanosecond lasers which hinders POC applications. Recently, light-emitting diodes (LEDs) have emerged as cost-effective and portable optical sources for the PAI of living subjects. However, state-of-art LED arrays carry significantly lower optical energy (<0.5 mJ/pulse) and high pulse repetition frequencies (PRFs) (4 KHz) compared to the high-power laser sources (100 mJ/pulse) with low PRFs of 10 Hz. Given these tradeoffs between portability, cost, optical energy and frame rate, this work systematically studies the deep tissue PAI performance of LED and laser illuminations to help select a suitable source for a given biomedical application. To draw a fair comparison, we developed a fiberoptic array that delivers laser illumination similar to the LED array and uses the same ultrasound transducer and data acquisition platform for PAI with these two illuminations. Several controlled studies on tissue phantoms demonstrated that portable LED arrays with high frame averaging show higher signal-to-noise ratios (SNRs) of up to 30 mm depth, and the high-energy laser source was found to be more effective for imaging depths greater than 30 mm at similar frame rates. Label-free in vivo imaging of human hand vasculature studies further confirmed that the vascular contrast from LED-PAI is similar to laser-PAI for up to 2 cm depths. Therefore, LED-PAI systems have strong potential to be a mobile health care technology for diagnosing vascular diseases such as peripheral arterial disease and stroke in POC and resource poor settings.

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Towards a Low-Cost and Portable Photoacoustic Microscope for Point-of-Care and Wearable Applications

Cited by 26 publications

References 41 publications

Efficient Parallel-Beamforming Based on Shared FIFO for Ultra-Compact Ultrasound Imaging Systems

Efficient Parallel-Beamforming Based on Shared FIFO for Ultra-Compact Ultrasound Imaging Systems

MEMS Ultrasound Transducers for Endoscopic Photoacoustic Imaging Applications

Photoacoustic Imaging of Human Vasculature Using LED versus Laser Illumination: A Comparison Study on Tissue Phantoms and In Vivo Humans

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