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Journal of Biomedical Optics

Rachael Hachadorian, Petr Bruza, Michael Jermyn, Amaan Mazhar, David Cuccia, Lesley Jarvis, David Gladstone, Brian Pogue
Imaging Cherenkov emission during radiotherapy permits real-time visualization of external beam delivery on superficial tissue. This signal is linear with absorbed dose in homogeneous media, indicating potential for quantitative dosimetry. In humans, the inherent heterogeneity of tissue optical properties (primarily from blood and skin pigment) distorts the linearity between detected Cherenkov signal and absorbed dose. We examine the potential to correct for superficial vasculature using spatial frequency domain imaging (SFDI) to map tissue optical properties for large fields of view...
November 2018: Journal of Biomedical Optics
Danielle E Desa, Michael G Nichols, Heather Jensen Smith
Despite causing permanent hearing loss by damaging inner ear sensory cells, aminoglycosides (AGs) remain one of the most widely used classes of antibiotics in the world. Although the mechanisms of cochlear sensory cell damage are not fully known, reactive oxygen species (ROS) are clearly implicated. Mitochondrial-specific ROS formation was evaluated in acutely cultured murine cochlear explants exposed to gentamicin (GM), a representative ototoxic AG antibiotic. Superoxide (O2·-) and hydrogen peroxide (H2O2) were measured using MitoSOX Red and Dihydrorhodamine 123, respectively, in sensory and supporting cells...
November 2018: Journal of Biomedical Optics
Pratik Samant, Timothy A Burt, Zhizhuang Joe Zhao, Liangzhong Xiang
Resolutions higher than the optical diffraction limit are often desired in the context of cellular imaging and the study of disease progression at the cellular level. However, three-dimensional super-resolution imaging without reliance on exogenous contrast agents has so far not been achieved. We present nanoscale photoacoustic tomography (nPAT), an imaging modality based on the photoacoustic effect. nPAT can achieve a dramatic improvement in the axial resolution of the photoacoustic imaging. We derive the theoretical resolution and sensitivity of nPAT and demonstrate that nPAT can achieve a maximum axial resolution of 9...
November 2018: Journal of Biomedical Optics
Tze-Ta Huang, Ken-Chung Chen, Tung-Yiu Wong, Chih-Yang Chen, Wang-Ch Chen, Yi-Chun Chen, Ming-Hsuan Chang, Dong-Yuan Wu, Teng-Yi Huang, Shoko Nioka, Pau-Choo Chung, Jehn-Shyun Huang
We created a two-channel autofluorescence test to detect oral cancer. The wavelengths 375 and 460 nm, with filters of 479 and 525 nm, were designed to excite and detect reduced-form nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) autofluorescence. Patients with oral cancer or with precancerous lesions, and a control group with healthy oral mucosae, were enrolled. The lesion in the autofluorescent image was the region of interest. The average intensity and heterogeneity of the NADH and FAD were calculated...
November 2018: Journal of Biomedical Optics
Eric Seifert, Jan Tode, Amelie Pielen, Dirk Theisen-Kunde, Carsten Framme, Johann Roider, Yoko Miura, Reginald Birngruber, Ralf Brinkmann
Selective retina therapy (SRT) targets the retinal pigment epithelium (RPE) with pulsed laser irradiation by inducing microbubble formation (MBF) at the intracellular melanin granula, which leads to selective cell disruption. The following wound healing process rejuvenates the chorio-retinal junction. Pulse energy thresholds for selective RPE effects vary intra- and interindividually. We present the evaluation of an algorithm that processes backscattered treatment light to detect MBF as an indicator of RPE cell damage since these RPE lesions are invisible during treatment...
November 2018: Journal of Biomedical Optics
Xianyu Wu, Mark Pankow, Hsiao-Ying Shadow Huang, Kara Peters
A high-speed polarization imaging instrument is demonstrated to be capable of measuring the collagen fiber alignment orientation and alignment strength during high-displacement rate dynamic loading at acquisition rates up to 10 kHz. The implementation of a high-speed rotating quarter wave plate and high-speed camera in the imaging system allows a minimum measurement acquisition time of 6 ms. Sliced tendon-to-bone insertion samples are loaded using a modified drop tower with an average maximum displacement rate of 1...
November 2018: Journal of Biomedical Optics
Naser Hakimi, Seyed Kamaledin Setarehdan
Many studies have been carried out in order to detect and quantify the level of mental stress by means of different physiological signals. From the physiological point of view, stress promptly affects brain and cardiac function; therefore, stress can be assessed by analyzing the brain- and heart-related signals more efficiently. Signals produced by functional near-infrared spectroscopy (fNIRS) of the brain together with the heart rate (HR) are employed to assess the stress induced by the Montreal Imaging Stress Task...
November 2018: Journal of Biomedical Optics
Felipe L Magalhães, Alexei M C Machado, Eduardo Paulino, Sangram K Sahoo, Ana M de Paula, Aloísio M Garcia, Ishan Barman, Jaqueline S Soares, Marcelo Mamede
Raman spectroscopy is widely used to investigate the structure and property of the molecules from their vibrational transitions and may allow for the diagnosis of cancer in a fast, objective, and nondestructive manner. This experimental study aims to propose the use of the 1064-nm wavelength laser in a Raman spectroscopy and to evaluate its discrimination capability in prostate cancer diagnosis. Seventy-four spectra from patients who underwent radical prostatectomy were evaluated. The acquired signals were filtered, normalized, and corrected for possible oscillations in the laser intensity and fluorescence effects...
November 2018: Journal of Biomedical Optics
James Hope, Bastian Braeuer, Satya Amirapu, Andrew McDaid, Frédérique Vanholsbeeck
We apply three optical coherence tomography (OCT) image analysis techniques to extract morphometric information from OCT images obtained on peripheral nerves of rat. The accuracy of each technique is evaluated against histological measurements accurate to +  /    -  1  μm. The three OCT techniques are: (1) average depth-resolved profile (ADRP), (2) autoregressive spectral estimation (AR-SE), and (3) correlation of the derivative spectral estimation (CoD-SE). We introduce a scanning window to the ADRP technique, which provides transverse resolution and improves epineurium thickness estimates-with the number of analyzed images showing agreement with histology increasing from 2  /  10 to 5  /  10 (Kruskal-Wallis test, α  =  0...
November 2018: Journal of Biomedical Optics
Dennis Wirth, Mira Sibai, Jonathan Olson, Brian C Wilson, David W Roberts, Keith Paulsen
Mapping the optical absorption and scattering properties of tissues using spatial frequency-domain imaging (SFDI) enhances quantitative fluorescence imaging of protoporphyrin IX (PpIX) in gliomas in the preclinical setting. The feasibility of using SFDI in the operating room was investigated here. A benchtop SFDI system was modified to mount directly to a commercial operating microscope. A digital light processing module imposed a selectable spatial light pattern from a broad-band xenon arc lamp to illuminate the surgical field...
October 2018: Journal of Biomedical Optics
Eric Brost, Yoichi Watanabe
Cerenkov light is created in clinical applications involving high-energy radiation such as in radiation therapy. There is considerable interest in using Cerenkov light as a means to perform in vivo dosimetry during radiation therapy; however, a better understanding of the light-to-dose relationship is needed. One such method to solve this relationship is that of a deconvolution formulation, which relies on the Cerenkov scatter function (CSF). The CSF describes the creation of Cerenkov photons by a pencil beam of high-energy radiation, and the subsequent scattering that occurs before emission from the irradiated medium surface...
October 2018: Journal of Biomedical Optics
Ryohei Hashimoto, Tomohiro Kurata, Masashi Sekine, Kazuya Nakano, Takashi Ohnishi, Hideaki Haneishi
Monitoring oxygen saturation (SO2) in microcirculation is effective for understanding disease dynamics. We have developed an SO2 estimation method, sidestream dark-field (SDF) oximetry, based on SDF imaging. SDF imaging is a noninvasive and clinically applicable technique to observe microcirculation. We report the first in vivo experiment observing the changes in SO2 of microcirculation using SDF oximetry. First, heat from the light-emitting diodes used for the SDF imaging might affect hemodynamics in microcirculation, hence, we performed an experiment to evaluate the influence of that on the SDF oximetry...
October 2018: Journal of Biomedical Optics
Benjamin W Maloney, David M McClatchy, Brian W Pogue, Keith D Paulsen, Wendy A Wells, Richard J Barth
Breast conserving surgery (BCS) is an effective treatment for early-stage cancers as long as the margins of the resected tissue are free of disease according to consensus guidelines for patient management. However, 15% to 35% of patients undergo a second surgery since malignant cells are found close to or at the margins of the original resection specimen. This review highlights imaging approaches being investigated to reduce the rate of positive margins, and they are reviewed with the assumption that a new system would need high sensitivity near 95% and specificity near 85%...
October 2018: Journal of Biomedical Optics
Andrei B Karpiouk, Donald J VanderLaan, Kirill V Larin, Stanislav Y Emelianov
Accurate measurements of microelastic properties of soft tissues in-vivo using optical coherence elastography can be affected by motion artifacts caused by cardiac and respiratory cycles. This problem can be overcome using a multielement ultrasound transducer probe where each ultrasound transducer is capable of generating acoustic radiation force (ARF) and, therefore, creating shear waves in tissue. These shear waves, produced during the phase of cardiac and respiratory cycles when tissues are effectively stationary, are detected at the same observation point using phase-sensitive optical coherence tomography (psOCT)...
October 2018: Journal of Biomedical Optics
Yunfei Wang, Yu Huang, Nan Zeng, Yihong Guo, Yonghong He, Hui Ma
Absorption effect is a basic optical phenomenon and an important feature in tissue imaging and characterization. Based on our Monte Carlo simulation on the anisotropic tissue model (sphere-cylinder birefringence model), combined with our experiments of tissue phantoms, we demonstrate the influence of absorption effect on Mueller matrix and particularly on depolarization, linear retardance, and diattenuation parameters. The simulation and experimental results show a good consistency on the suppressed depolarization and scatterering induced retardance, and the enhanced diattenuation caused by the absorption, and also indicate the birefringence induced retardance insensitive to the absorption...
October 2018: Journal of Biomedical Optics
Supriya V Thathachary, Shai Ashkenazi
In recent times, there has been extensive research on fiber-optic imaging devices in order to enable imaging/sensing at a size scale inaccessible to other modalities. The design for fabrication of a highly sensitive fiber-optic ultrasound detector is proposed. The transducer employs a polymer Fabry-Pérot resonator for ultrasound detection. To enhance acoustic sensitivity, a method is proposed for fabricating a self-aligned polymer waveguide within the cavity to improve the resonator quality factor (Q-factor)...
October 2018: Journal of Biomedical Optics
Dween Rabius Sanny, Jaya Prakash, Sandeep Kumar Kalva, Manojit Pramanik, Phaneendra K Yalavarthy
Photoacoustic tomography tends to be an ill-conditioned problem with noisy limited data requiring imposition of regularization constraints, such as standard Tikhonov (ST) or total variation (TV), to reconstruct meaningful initial pressure rise distribution from the tomographic acoustic measurements acquired at the boundary of the tissue. However, these regularization schemes do not account for nonuniform sensitivity arising due to limited detector placement at the boundary of tissue as well as other system parameters...
October 2018: Journal of Biomedical Optics
A Siri Luthman, Dale J Waterhouse, Laura Ansel-Bollepalli, Jonghee Yoon, George S D Gordon, James Joseph, Massimiliano di Pietro, Wladyslaw Januszewicz, Sarah E Bohndiek
Emerging clinical interest in combining standard white light endoscopy with targeted near-infrared (NIR) fluorescent contrast agents for improved early cancer detection has created demand for multimodal imaging endoscopes. We used two spectrally resolving detector arrays (SRDAs) to realize a bimodal endoscope capable of simultaneous reflectance-based imaging in the visible spectral region and multiplexed fluorescence-based imaging in the NIR. The visible SRDA was composed of 16 spectral bands, with peak wavelengths in the range of 463 to 648 nm and full-width at half-maximum (FWHM) between 9 and 26 nm...
October 2018: Journal of Biomedical Optics
(no author information available yet)
This erratum corrects an error in "Diagnosis of malignant pleural mesothelioma from pleural fluid by Fourier transform-infrared spectroscopy coupled with chemometrics," by Sherif Abbas et al.
October 2018: Journal of Biomedical Optics
Meha Qassem, Iasonas Triantis, Michelle Hickey, Eleni Palazidou, Panayiotis Kyriacou
Bipolar disorder (BD) is a common mental health condition, characterized by extreme changes in mood, energy, and behavior. BD is often managed through mood-stabilizing medications, of which lithium formulations remain the most reliable and effective at reducing the risk of suicide. To achieve adequate and consistent efficacy, lithium concentrations need to be maintained within a narrow therapeutic range (0.4 to 1.2  mmol  /  L). Because of its narrow therapeutic index, long-term lithium therapy is associated with serious side effects and risks of toxicity...
October 2018: Journal of Biomedical Optics
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