scholarly journals Near-Infrared Diffuse Optical Tomography

2002 ◽  
Vol 18 (5-6) ◽  
pp. 313-337 ◽  
Author(s):  
A. H. Hielscher ◽  
A. Y. Bluestone ◽  
G. S. Abdoulaev ◽  
A. D. Klose ◽  
J. Lasker ◽  
...  
Keyword(s):  
Near Infrared ◽  
Imaging Modality ◽  
Low Cost ◽  
Optical Tomography ◽  
Diffuse Optical Tomography ◽  
Biological Tissues ◽  
Body Parts ◽  
Reconstruction Algorithms ◽  
Cross Sectional ◽  
Magnetic Resonance Imaging Mri

Diffuse optical tomography (DOT) is emerging as a viable new biomedical imaging modality. Using near-infrared (NIR) light, this technique probes absorption as well as scattering properties of biological tissues. First commercial instruments are now available that allow users to obtain cross-sectional and volumetric views of various body parts. Currently, the main applications are brain, breast, limb, joint, and fluorescence/bioluminescence imaging. Although the spatial resolution is limited when compared with other imaging modalities, such as magnetic resonance imaging (MRI) or X-ray computerized tomography (CT), DOT provides access to a variety of physiological parameters that otherwise are not accessible, including sub-second imaging of hemodynamics and other fast-changing processes. Furthermore, DOT can be realized in compact, portable instrumentation that allows for bedside monitoring at relatively low cost. In this paper, we present an overview of current state-of-the -art technology, including hardware and image-reconstruction algorithms, and focus on applications in brain and joint imaging. In addition, we present recent results of work on optical tomographic imaging in small animals.

Conventional uroradiology with excretory urography: a forgotten art?

2022 ◽  
Author(s):  
Prateek Kumar Madaan ◽  
Rohini Gupta Ghasi
Keyword(s):  
Imaging Modality ◽  
Low Cost ◽  
Excretory Urography ◽  
Resonance Imaging ◽  
Dynamic Nature ◽  
Cross Sectional ◽  
Radiation Burden ◽  
The Past ◽  
Key Points ◽  
Magnetic Resonance Imaging Mri

Excretory urography (EU) had been the most frequently performed imaging modality for uroradiology in the past. With the advances in Ultrasonography, and development of cross-sectional urography with Computed tomography (CT) and Magnetic resonance Imaging (MRI), EU is now seldom performed. Consequently, there has been a decline of expertise in this technique. However, EU has multiple advantages such as dynamic nature, easy availability, low cost and radiation burden. These render it potentially very valuable in specific indications like congenital anomalies, urothelial lesions and urinary leaks. This review intends to emphasize the current day relevance of excretory urography, outline the key points of the technique, and describe the pearls and pitfalls of interpretation.

Time-Resolved Diffuse Optical Tomography of Human Forearm Under Exercise

2011 ◽  
Author(s):  
Yasuomi Endo ◽  
Yukari Tanikawa ◽  
Shinpei Okawa ◽  
Kazuto Masamoto ◽  
Hidetaka Okada ◽  
...  
Keyword(s):  
Near Infrared ◽  
Optical Tomography ◽  
Diffuse Optical Tomography ◽  
Biological Tissues ◽  
Magnetic Resonance Images ◽  
Time Resolved ◽  
Tomographic Images ◽  
Infrared Wavelength ◽  
Flexion And Extension ◽  
Absorption Characteristics

Light in the near-infrared wavelength range can penetrate deeping into biological tissues because the absorption by both water and hemoglobin is much smaller than in the other wavelength ranges. Oxygenated and deoxygenated hemoglobins have different light absorption characteristics. Therefore, by obtaining tomographic images of the absorption characteristics, it will be possible to know the hemodynamics inside deep tissues. Thus, the diffuse optical tomography (DOT) is expected as a new modality of biomedical imaging. In this study, we try to obtain DOT images of the forearms by conducting two types of exercise, and their differences caused by the muscle activity are discussed. By comparing the reconstructed DOT images with the magnetic resonance images of the forearm at the same position, the activated muscles can be identified in detail. As a result, the hemodynamics in the dominant muscles when performing flexion and extension of wrist are observed.

scholarly journals Breast Tumor Detection Instrument Through Mammography Based NIR DOT

2010 ◽  
Vol 4 (2) ◽  
Author(s):  
Jun-Yu Chen ◽  
H.-Z. Jiang ◽  
L.-Y. Chen ◽  
Min-Chun Pan ◽  
Ch.-T. Wu ◽  
...  
Keyword(s):  
Near Infrared ◽  
Multimodality Imaging ◽  
Imaging Modality ◽  
Optical Tomography ◽  
Diffuse Optical Tomography ◽  
Breast Tumors ◽  
Imaging Method ◽  
Channel Switching ◽  
X Ray ◽  
Multiple Channel

X-ray mammography has been used in the early detection of breast tumors for decades. Related techniques to enhance preventive screenings are still demanding. Since the 1990s, near infrared diffuse optical tomography (NIR DOT), a functional medical imaging modality, is being exploited and developed to reconstruct optical-coefficient images of tissues. Much endeavor to improve the spatial resolution and contrast of DOT images has been exerted for clinic applications in the diagnosis of breast tumors. The study aims at the design, implementation, and verification of a mammography based NIR DOT. This multimodality imaging method is able to provide information that neither X-ray nor diffuse optical tomography can give alone. To this end, a device with multiple-channel switching of NIR sources and translational scanning of out-emitted intensity constructed on a commercialized mammography system is being designed and built up. We employ the mammography image as structure information that is used as an initial guess for the image reconstruction of optical properties of tissues. Preliminary numerical trials are performed using heterogeneous phantoms made of high-scattering Intralipid. Promising results are obtained with various spatial resolutions due to partial NIR detected intensity.

Acceleration of the EM-like reconstruction method for diffuse optical tomography with ordered-subsets method

2014 ◽  
Vol 22 (3) ◽  
Author(s):  
Caifang Wang
Keyword(s):  
Numerical Experiments ◽  
Imaging Modality ◽  
Random Medium ◽  
Optical Tomography ◽  
Back Propagation ◽  
Three Dimensional ◽  
Diffuse Optical Tomography ◽  
Optical Parameters ◽  
Reconstruction Method ◽  
Boundary Measurements

Abstract.Diffuse optical tomography (DOT) is an optical imaging modality, which provides the spatial distribution of the optical parameters inside a random medium. A propagation back-propagation method named EM-like reconstruction method for stationary DOT problem has been proposed yet. This method is really time consuming. Hence the ordered-subsets (OS) technique for this reconstruction method is studied in this paper. The boundary measurements of DOT are grouped into nonoverlapping and overlapping ordered sequence of subsets with random partition, sequential partition and periodic partition, respectively. The performance of OS methods is compared with the standard EM-like reconstruction method with two-dimensional and three-dimensional numerical experiments. The numerical experiments indicate that reconstruction of nonoverlapping subsets with periodic partition, overlapping subsets with periodic partition and standard EM-like method provide very similar acceptable reconstruction results. However, reconstruction of nonoverlapping subsets with periodic partition spends a minimum of time to get proper results.

scholarly journals Design and implementation of a multifrequency near-infrared diffuse optical tomography system

2006 ◽  
Vol 11 (1) ◽  
pp. 014020 ◽  
Author(s):  
Gultekin Gulsen ◽  
Bin Xiong ◽  
Ozlem Birgul ◽  
Orhan Nalcioglu
Keyword(s):  
Near Infrared ◽  
Optical Tomography ◽  
Diffuse Optical Tomography ◽  
Design And Implementation ◽  
Tomography System

scholarly journals Optimal Analysis Method for Dynamic Contrast-Enhanced Diffuse Optical Tomography

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Michael Ghijsen ◽  
Yuting Lin ◽  
Mitchell Hsing ◽  
Orhan Nalcioglu ◽  
Gultekin Gulsen
Keyword(s):  
Spatial Resolution ◽  
Animal Studies ◽  
Imaging Modality ◽  
A Priori ◽  
Optical Tomography ◽  
Diffuse Optical Tomography ◽  
Dynamic Contrast Enhanced ◽  
Promising Tool ◽  
Reconstruction Methods ◽  
Contrast Enhanced

Diffuse Optical Tomography (DOT) is an optical imaging modality that has various clinical applications. However, the spatial resolution and quantitative accuracy of DOT is poor due to strong photon scatting in biological tissue. Structurala prioriinformation from another high spatial resolution imaging modality such as Magnetic Resonance Imaging (MRI) has been demonstrated to significantly improve DOT accuracy. In addition, a contrast agent can be used to obtain differential absorption images of the lesion by using dynamic contrast enhanced DOT (DCE-DOT). This produces a relative absorption map that consists of subtracting a reconstructed baseline image from reconstructed images in which optical contrast is included. In this study, we investigated and compared different reconstruction methods and analysis approaches for regular endogenous DOT and DCE-DOT with and without MR anatomicala prioriinformation for arbitrarily-shaped objects. Our phantom and animal studies have shown that superior image quality and higher accuracy can be achieved using DCE-DOT together with MR structurala prioriinformation. Hence, implementation of a combined MRI-DOT system to image ICG enhancement can potentially be a promising tool for breast cancer imaging.

scholarly journals Real-Time Dual-Wavelength Time-Resolved Diffuse Optical Tomography System for Functional Brain Imaging Based on Probe-Hosted Silicon Photomultipliers

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2815
Author(s):  
David Orive-Miguel ◽  
Laura Di Sieno ◽  
Anurag Behera ◽  
Edoardo Ferocino ◽  
Davide Contini ◽  
...  
Keyword(s):  
Brain Imaging ◽  
Near Infrared ◽  
Optical Tomography ◽  
Diffuse Optical Tomography ◽  
Brain Activation ◽  
Functional Brain Imaging ◽  
Dual Wavelength ◽  
Silicon Photomultipliers ◽  
Functional Brain ◽  
Tomography System

Near-infrared diffuse optical tomography is a non-invasive photonics-based imaging technology suited to functional brain imaging applications. Recent developments have proved that it is possible to build a compact time-domain diffuse optical tomography system based on silicon photomultipliers (SiPM) detectors. The system presented in this paper was equipped with the same eight SiPM probe-hosted detectors, but was upgraded with six injection fibers to shine the sample at several points. Moreover, an automatic switch was included enabling a complete measurement to be performed in less than one second. Further, the system was provided with a dual-wavelength (670 n m and 820 n m ) light source to quantify the oxy- and deoxy-hemoglobin concentration evolution in the tissue. This novel system was challenged against a solid phantom experiment, and two in-vivo tests, namely arm occlusion and motor cortex brain activation. The results show that the tomographic system makes it possible to follow the evolution of brain activation over time with a 1 s -resolution.

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