• Title, Summary, Keyword: Photoacoustic imaging

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Review of Photoacoustic Imaging for Imaging-Guided Spinal Surgery

  • Han, Seung Hee
    • Neurospine
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    • v.15 no.4
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    • pp.306-322
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    • 2018
  • This review introduces the current technique of photoacoustic imaging as it is applied in imaging-guided surgery (IGS), which provides the surgeon with image visualization and analysis capabilities during surgery. Numerous imaging techniques have been developed to help surgeons perform complex operations more safely and quickly. Although surgeons typically use these kinds of images to visualize targets hidden by bone and other tissues, it is nonetheless more difficult to perform surgery with static reference images (e.g., computed tomography scans and magnetic resonance images) of internal structures. Photoacoustic imaging could enable real-time visualization of regions of interest during surgery. Several researchers have shown that photoacoustic imaging has potential for the noninvasive diagnosis of various types of tissues, including bone. Previous studies of the surgical application of photoacoustic imaging have focused on cancer surgery, but photoacoustic imaging has also recently attracted interest for spinal surgery, because it could be useful for avoiding pedicle breaches and for choosing an appropriate starting point before drilling or pedicle probe insertion. This review describes the current instruments and clinical applications of photoacoustic imaging. Its primary objective is to provide a comprehensive overview of photoacoustic IGS in spinal surgery.

Array-Based Real-Time Ultrasound and Photoacoustic Ocular Imaging

  • Nam, Seung Yun;Emelianov, Stanislav Y.
    • Journal of the Optical Society of Korea
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    • v.18 no.2
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    • pp.151-155
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    • 2014
  • Although various ophthalmic imaging methods, including fundus photography and optical coherence tomography, have been applied for effective diagnosis of ocular diseases with high spatial resolution, most of them are limited by shallow imaging penetration depth and a narrow field of view. Also, many of those imaging modalities are optimized to provide microscopic anatomical information, while functional or cellular information is lacking. Compared to other ocular imaging modalities, photoacoustic imaging can achieve relatively deep penetration depth and provide more detailed functional and cellular data based on photoacoustic signal generation from endogenous contrast agents such as hemoglobin and melanin. In this paper, array-based ultrasound and photoacoustic imaging was demonstrated to visualize pigmentation in the eye as well as overall ocular structure. Fresh porcine eyes were visualized using a real-time ultrasound micro-imaging system and an imaging probe supporting laser pulse delivery. In addition, limited photoacoustic imaging field of view was improved by an imaging probe tilting method, enabling visualization of most regions of the retina covered in the ultrasound imaging.

A Preliminary Study on Developing a Photoacoustic Imaging System for Inflammatory Arthritis Diagnosis (관절염 진단용 광음향 이미징 시스템 개발을 위한 선행 연구)

  • Youn, Jong-In;Park, Ji-Won
    • The Journal of Korean Physical Therapy
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    • v.22 no.4
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    • pp.83-89
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    • 2010
  • Purpose: The goal of this study was to investigate the feasibility for the early diagnosis of inflammatory arthritis by the reconstruction of three-dimensional photoacoustic imaging with a tissue phantom. Methods: Q-switched Nd:YAG laser (l = 532 nm) was applied to a tissue phantom to generate photoacoustic waves, and the acquired photoacoustic signals at different positions around the sample were used to recombine the distribution of the optical absorption and the images were subsequently generated through a reconstruction algorithm. Results: From the acquired photoacoustic signals, the surface andinner core of the phantom was clearly distinguished. Furthermore, the back-projection algorithm was able to reconstruct two-dimensional and three-dimensional photoacoustic images that contained the optical absorption property information of the tissue phantom. Conclusion: The results indicate that the photoacoustic imaging technique has many advantages such as high optical contrast and high acoustic resolution. The acquired images can be used for the early diagnosis of inflammatory arthritis by the structural information obtained from the region of interest.

In vivo functional photoacoustic imaging (나노초 레이져를 이용한 광-초음파 이미지 결상법)

  • Oh, Jung-Taek;Li, Meng-Lin;Song, Kwang-Hyun;Xie, Xueyi;Stoica, George;Wang, Lihong V.
    • Proceedings of the Optical Society of Korea Conference
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    • pp.359-360
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    • 2006
  • Functional photoacoustic tomography is a new non-invasive imaging modality, and it is emerging as a very practical method for imaging biological tissue structures by means of laser-induced ultrasound. Structures with high optical absorption, such as blood vessels, can be imaged with the spatial resolution of ultrasound, which is not limited by the strong light scattering in biological tissues. By varying wavelengths of the laser light and acquiring photoacoustic images, optical absorption spectrum of each image pixel is found. Since the biochemical constituents of tissues determine the spectrum, useful functional information like oxygen saturation ($SO_2$) and total haemoglobin concentration (HbT) can be extracted. In this study, as a proof-of-principle experiment, hypoxic brain tumor vasculature and traumatic brain injury (TBI) of small animal brain are imaged with functional photoacoustic tomography. High resolution brain vasculature images of oxygen saturation and total hemoglobin concentration are provided to visualize hypoxic tumor vasculature, and hemorrhage on the cortex surface by the TBI.

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Clinically translatable photoacoustic imaging of cancer diagnosis (임상적용이 가능한 광음향 암 진단 기술)

  • Kim, Mi-Ji;Park, Yeon-Seong;Yoon, Changhan
    • The Journal of the Acoustical Society of Korea
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    • v.38 no.4
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    • pp.476-484
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    • 2019
  • Photoacoustic imaging is a hybrid real-time imaging technique that combines high optical contrast and ultrasonic resolution. It has primarily been utilized in pre-clinical research and has evolved into clinical practice. In this paper, we review photoacosutic imaging for detection of primary canccer and metastatis and its limitation in translation from pre-clinical to clinical application.

Principles and Medical Applications of Biomedical Photoacoustic Tomography (의료용 광음향 단층촬영 원리와 의학적 응용)

  • Song, Chul-Gyu;Ryu, Sang-Hun;Kim, Do-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.6
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    • pp.1209-1214
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    • 2011
  • Photoacoustics has been broadly studied in biomedicine, for both human and small animal tissues. Photoacoustics uniquely combines the absorption contrast of light or radio frequency waves with ultrasound resolution. Moreover, it is non-ionizing and non-invasive, and is the fastest growing new biomedical method, with clinical applications on the way. This paper provides a brief recap of recent developments in photoacoustics in biomedicine, from basic principles to applications. The emphasized areas include the new imaging modalities as well as translational research topics. A primary PA application in biomedicine is photoacoustic tomography (PAT). The past decade has seen fast developments in both theoretical reconstruction algorithms and innovative imaging techniques, and PAT has been implemented in imaging different tissues, from centimeter-large breast tumors to several micrometer-large single red blood cels (RBC). PAT now provides structural, functional and molecular imaging. Overall, PA techniques for biomedicine are maturing. They have been widely used to study both animal and human tissues. Recently, more and more research focuses on clinical applications. Commercialized PA systems are expected to be available in the near future, and wide clinical PA applications are foreseen.

Fabrication and Characterization of PVCP Human Breast Tissue-mimicking Phantom for Photoacoustic Imaging

  • Jeong, Eun-ju;Song, Hyun-Woo;Lee, Yong-Jae;Park, Su Jun;Yim, Mi Jung;Lee, Su Sung;Kim, Bong Kyu
    • BioChip Journal
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    • v.11 no.1
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    • pp.67-75
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    • 2017
  • Human tissue-mimicking phantoms are important for characterizing and optimizing ultrasound and photoacoustic imaging systems. We demonstrated the applicability of a polyvinyl chloride plastisol (PVCP) phantom to photoacoustic imaging studies. The acoustic properties of the fabricated PVCP phantom were measured to have a sound speed of 1370 m/s, attenuation coefficient of 0.71 dB/cm/MHz, and acoustic impedance of 1.39 Mrayl. Reduced scattering coefficients, absorption coefficient, and refractive index were obtained, as $1.31mm^{-1}$, $0.001mm^{-1}$, and 1.636 at 780 nm by optical measurements, respectively. Therefore, the PVCP phantom was found to be similar enough to human breast tissue in photoacoustic properties.

Development of Laser Induced Real Time Photoacoustic Tomography Imaging System and Phantom Evaluation (레이저 유도방식의 실시간 광음향 단층영상 기술 개발과 팬텀이미지 평가)

  • Ryu, Sang-Hun;Shin, Dong-Ho;Song, Chul-Gyu
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.6
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    • pp.879-884
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    • 2012
  • Photoacoustic Tomography (PAT) is a promising medical imaging modality by reason of its particularity. It combines optical imaging contrast of optical imaging with the spatial resolution of ultrasound imaging and can demonstrate change of biological feature in an image. For that reason, many studies are in progress to apply this technic for diagnosis. But, real-time PAT system is necessary to confirm a biological reaction induced by external stimulation immediately. Thus, we developed a real-time PAT system using linear array transducer and self-developed Data acquisition board (DAQ) resources, To evaluate the feasibility and performance of our proposed system, two type of phantom test were also performed. As a result of those experiments, the proposed system shows enough performance and confirm its usefulness.

Contrast-enhanced dual mode imaging: photoacoustic imaging plus more

  • Park, Sungjo;Jung, Unsang;Lee, Seunghyun;Lee, Donghyun;Kim, Chulhong
    • Biomedical Engineering Letters
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    • v.7 no.2
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    • pp.121-133
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    • 2017
  • Conventional biomedical imaging modalities in wide clinical use, such as ultrasound imaging, X-ray computed tomography, magnetic resonance imaging, and positron emission tomography, can provide morphological, anatomical, and functional information about biological tissues. However, single mode imaging in conventional medicine provides only limited information for definitive diagnoses. Thus, combinational diagnosis using multiple imaging modalities has become increasingly important. Recently, photoacoustic imaging (PAI) has gained significant attention, and several PAI prototypes have been used in clinical trials. At the same time, PAI has been tested in combination with conventional imaging modalities. For all these imaging modalities, various contrast-enhancing agents have been developed for various purposes. In this review article, we will focus on recent progress in developing dual mode contrast agents for PAI in combination with other conventional imaging modalities.

Phantom Evaluation and Development of Photoacoustic Tomography Imaging System using Unfocused Ultrasound Transducer and Back-Projection Algorithm (역투사 알고리듬과 비촛점 트랜스듀서를 적용한 광음향 단층영상 장치개발과 팬텀실험)

  • Ryu, Sang-Hun;Kim, Do-Hyun;Song, Chul-Gyu
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.12
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    • pp.2349-2351
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    • 2010
  • Photo Acoustic Tomography (PAT) is a hybrid imaging modality which combines high contrast of optical imaging and spatial resolution of ultrasound imaging, thus it is suitable to image biological tissue noninvasively. Laser-induced photoacoustic signals were measured from a sample by means of an unfocused ultrasound transducer, then PAT image was reconstructed based on a universal back-projection algorithm. To evaluate the feasibility of our system, phantom test was performed, consequently, the PAT images obtained using our system showed highly analogous shape and volume with those of the phantom. This result demonstrated that our system can provide a powerful tool for imaging the substructure of biological tissue in non-invasive manner.