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Biomedical Optics Express

Dongwoo Koo, Hyun-Cheol Park, Peter L Gehlbach, Cheol Song
Bimanual surgery enhances surgical effectiveness and is required to successfully accomplish complex microsurgical tasks. The essential advantage is the ability to simultaneously grasp tissue with one hand to provide counter traction or exposure, while dissecting with the other. Towards enhancing the precision and safety of bimanual microsurgery we present a bimanual SMART micro-surgical system for a preliminary ex-vivo study. To the best of our knowledge, this is the first demonstration of a handheld bimanual microsurgical system...
November 1, 2016: Biomedical Optics Express
Kuen-Che Li, Lynn L H Huang, Jhih-Hao Liang, Ming-Che Chan
A simple approach to multi-color two-photon microscopy of the red, green, and blue fluorescent indicators was reported based on an ultra-compact 1.03-μm femtosecond laser and a nonlinear fiber. Inside the nonlinear fiber, the 1.03-μm laser pulses were simultaneously blue-shifted to 0.6~0.8 μm and red-shifted to 1.2~1.4 μm region by the Cherenkov radiation and fiber Raman gain effects. The wavelength-shifted 0.6~0.8 μm and 1.2~1.4 μm radiations were co-propagated with the residual non-converted 1.03-μm pulses inside the same nonlinear fiber to form a fiber-output three-color femtosecond source...
November 1, 2016: Biomedical Optics Express
Jaebum Chung, Hangwen Lu, Xiaoze Ou, Haojiang Zhou, Changhuei Yang
Fourier ptychographic (FP) microscopy is a coherent imaging method that can synthesize an image with a higher bandwidth using multiple low-bandwidth images captured at different spatial frequency regions. The method's demand for multiple images drives the need for a brighter illumination scheme and a high-frame-rate camera for a faster acquisition. We report the use of a guided laser beam as an illumination source for an FP microscope. It uses a mirror array and a 2-dimensional scanning Galvo mirror system to provide a sample with plane-wave illuminations at diverse incidence angles...
November 1, 2016: Biomedical Optics Express
Hao Yang Wu, Andrew Filer, Iain Styles, Hamid Dehghani
A multi-wavelength diffuse optical tomography (DOT) system has been developed to directly extract physiological information, such as total haemoglobin concentration, from tissue in human hand joints. Novel methods for 3D surface imaging and spectrally constrained image reconstruction are introduced and their potential application to imaging of rheumatoid arthritis is discussed. Results are presented from simulation studies as well as experiments using phantoms and data from imaging of three healthy volunteers...
November 1, 2016: Biomedical Optics Express
Jun Liao, Liheng Bian, Zichao Bian, Zibang Zhang, Charmi Patel, Kazunori Hoshino, Yonina C Eldar, Guoan Zheng
A critical consideration for whole slide imaging (WSI) platform is to perform accurate autofocusing at high speed. Typical WSI systems acquire a z-stack of sample images and determine the best focal position by maximizing a figure of merit. This strategy, however, has suffered from several limitations, including low speed due to multiple image acquisitions, relatively low accuracy of focal plane estimation, short axial range for autofocusing, and difficulties in handling transparent samples. By exploring the autocorrelation property of the tissue sections, we report a novel single-frame autofocusing scheme to address the above challenges...
November 1, 2016: Biomedical Optics Express
Wenli Wu, Andrew J Radosevich, Adam Eshein, The-Quyen Nguyen, Ji Yi, Lusik Cherkezyan, Hemant K Roy, Igal Szleifer, Vadim Backman
The microscopic structural origins of optical properties in biological media are still not fully understood. Better understanding these origins can serve to improve the utility of existing techniques and facilitate the discovery of other novel techniques. We propose a novel analysis technique using electron microscopy (EM) to calculate optical properties of specific biological structures. This method is demonstrated with images of human epithelial colon cell nuclei. The spectrum of anisotropy factor g, the phase function and the shape factor D of the nuclei are calculated...
November 1, 2016: Biomedical Optics Express
Shaozhen Song, Jingjiang Xu, Ruikang K Wang
Current optical coherence tomography (OCT) imaging suffers from short ranging distance and narrow imaging field of view (FOV). There is growing interest in searching for solutions to these limitations in order to expand further in vivo OCT applications. This paper describes a solution where we utilize an akinetic swept source for OCT implementation to enable ~10 cm ranging distance, associated with the use of a wide-angle camera lens in the sample arm to provide a FOV of ~20 x 20 cm(2). The akinetic swept source operates at 1300 nm central wavelength with a bandwidth of 100 nm...
November 1, 2016: Biomedical Optics Express
Andreia Vieira Moço, Sander Stuijk, Gerard de Haan
Remote photoplethysmography (rPPG) imaging is an optical technique to remotely assess the local cutaneous microcirculation. Despite its potential for enabling health-related applications, the current understanding of the outcome images/maps remains incomplete. In this paper, we present a model and supporting experiments confirming the contribution of skin inhomogeneity to the morphology of PPG waveforms. Since rPPG imagers rely on the complex inner-product operator and may combine multiple wavelengths, the derived phase measurements reflect morphological heterogeneity of PPG signals to a larger extent than propagation-related phase differences...
November 1, 2016: Biomedical Optics Express
Yuezhi He, Benjamin S-Y Ung, Edward P J Parrott, Anil T Ahuja, Emma Pickwell-MacPherson
There have recently been several studies published involving terahertz (THz) imaging of frozen biomedical samples. In this paper, we investigate the effects of the freeze-thaw cycle on THz properties of porcine muscle and fat samples. For ordinary freezing, there was a significant change in the THz properties after thawing for muscle tissue but not for fat tissue. However, if snap-freezing was combined with fast-thawing instead of ordinary freezing and ordinary thawing, then the freeze-thaw hysteresis was removed...
November 1, 2016: Biomedical Optics Express
Yi Qiu, Farzana R Zaki, Namas Chandra, Shawn A Chester, Xuan Liu
Optical coherence elastography (OCE) has been used to perform mechanical characterization on biological tissue at the microscopic scale. In this work, we used quantitative optical coherence elastography (qOCE), a novel technology we recently developed, to study the nonlinear elastic behavior of biological tissue. The qOCE system had a fiber-optic probe to exert a compressive force to deform tissue under the tip of the probe. Using the space-division multiplexed optical coherence tomography (OCT) signal detected by a spectral domain OCT engine, we were able to simultaneously quantify the probe deformation that was proportional to the force applied, and to quantify the tissue deformation...
November 1, 2016: Biomedical Optics Express
Idit Feder, Maciej Wróbel, Hamootal Duadi, Małgorzata Jędrzejewska-Szczerska, Dror Fixler
Human tissue is one of the most complex optical media since it is turbid and nonhomogeneous. We suggest a new optical method for sensing physiological tissue state, based on the collection of the ejected light at all exit angles, to receive the full scattering profile. We built a unique set-up for noninvasive encircled measurement. We use a laser, a photodetector and finger tissues-mimicking phantoms presenting different optical properties. Our method reveals an isobaric point, which is independent of the optical properties...
November 1, 2016: Biomedical Optics Express
Linhui Yu, Ying Wu, Jeff F Dunn, Kartikeya Murari
We propose a single fiber optical system for monitoring tissue oxygen saturation (sO2) based on continuous-wave reflectance spectroscopy in the visible wavelengths. The system is designed for measurements in deep brain structures by stereotaxically implanting the 200 μm-core fiber probe into the tissue of interest. Monte Carlo (MC) simulations were used to estimate the measurement tissue volume between 0.02-0.03 mm(3). Experiments in an optical phantom indicated the system had a root mean squared error (RMSE) of 4...
November 1, 2016: Biomedical Optics Express
Ikbal Sencan, Brendan K Huang, Yong Bian, Emily Mis, Mustafa K Khokha, Hui Cao, Michael Choma
We developed ultra-high-speed, phase-sensitive, full-field reflection interferometric confocal microscopy (FFICM) for the quantitative characterization of in vivo microscale biological motions and flows. We demonstrated 2D frame rates in excess of 1 kHz and pixel throughput rates up to 125 MHz. These fast FFICM frame rates were enabled by the use of a low spatial coherence, high-power laser source. Specifically, we used a dense vertical cavity surface emitting laser (VCSEL) array that synthesized low spatial coherence light through a large number of narrowband, mutually-incoherent emitters...
November 1, 2016: Biomedical Optics Express
Christian Crouzet, Robert H Wilson, Afsheen Bazrafkan, Maryam H Farahabadi, Donald Lee, Juan Alcocer, Bruce J Tromberg, Bernard Choi, Yama Akbari
In the present study, we have developed a multi-modal instrument that combines laser speckle imaging, arterial blood pressure, and electroencephalography (EEG) to quantitatively assess cerebral blood flow (CBF), mean arterial pressure (MAP), and brain electrophysiology before, during, and after asphyxial cardiac arrest (CA) and resuscitation. Using the acquired data, we quantified the time and magnitude of the CBF hyperemic peak and stabilized hypoperfusion after resuscitation. Furthermore, we assessed the correlation between CBF and MAP before and after stabilized hypoperfusion...
November 1, 2016: Biomedical Optics Express
Kevin A Hatch, Alfredo Ornelas, Kaitlyn N Williams, Thomas Boland, Katja Michael, Chunqiang Li
N-acyl-7-nitroindolines have been used as caged compounds to photorelease active molecules by a one- or two-photon excitation mechanism in biological systems. Here, we report the photolysis of a polypeptide that contains 7-nitroindoline units as linker moieties in its peptide backbone for potential materials engineering applications. Upon two-photon excitation with femtosecond laser light at 710 nm the photoreactive amide bond in N-peptidyl-7-nitroindolines is cleaved rendering short peptide fragments. Thus, this photochemical process changes the molecular composition at the laser focal volume...
November 1, 2016: Biomedical Optics Express
Kaushik Subramanian, Ilan Gabay, Onur Ferhanoğlu, Adam Shadfan, Michal Pawlowski, Ye Wang, Tomasz Tkaczyk, Adela Ben-Yakar
We present the development of a 5 mm, piezo-actuated, ultrafast laser scalpel for fast tissue microsurgery. Delivery of micro-Joules level energies to the tissue was made possible by a large, 31 μm, air-cored inhibited-coupling Kagome fiber. We overcome the fiber's low NA by using lenses made of high refractive index ZnS, which produced an optimal focusing condition with 0.23 NA objective. The optical design achieved a focused laser spot size of 4.5 μm diameter covering a 75 × 75 μm(2) scan area in a miniaturized setting...
November 1, 2016: Biomedical Optics Express
Masahiro Yamanari, Satoru Tsuda, Taiki Kokubun, Yukihiro Shiga, Kazuko Omodaka, Naoko Aizawa, Yu Yokoyama, Noriko Himori, Shiho Kunimatsu-Sanuki, Kazuichi Maruyama, Hiroshi Kunikata, Toru Nakazawa
[This corrects the article on p. 3551 in vol. 7, PMID: 27699120.].
November 1, 2016: Biomedical Optics Express
Dan MacDougall, Joshua Farrell, Jeremy Brown, Manohar Bance, Robert Adamson
We present the design, implementation and validation of a swept-source optical coherence tomography (OCT) system for real-time imaging of the human middle ear in live patients. Our system consists of a highly phase-stable Vernier-tuned distributed Bragg-reflector laser along with a real-time processing engine implemented on a graphics processing unit. We use the system to demonstrate, for the first time in live subjects, real-time Doppler measurements of middle ear vibration in response to sound, video rate 2D B-mode imaging of the middle ear and 3D volumetric B-mode imaging...
November 1, 2016: Biomedical Optics Express
Carlos Dorronsoro, Aiswaryah Radhakrishnan, Pablo De Gracia, Lucie Sawides, Susana Marcos
[This corrects the article on p. 4388 in vol. 7.].
November 1, 2016: Biomedical Optics Express
Nassim Nasseri, Stefan Kleiser, Daniel Ostojic, Tanja Karen, Martin Wolf
Change of muscle tissue oxygen saturation (StO2), due to exercise, measured by near infrared spectroscopy (NIRS) is known to be lower for subjects with higher adipose tissue thickness. This is most likely not physiological but caused by the superficial fat and adipose tissue. In this paper we assessed, in vitro, the influence of adipose tissue thickness on muscle StO2, measured by NIRS oximeters. We measured StO2 of a liquid phantom by 3 continuous wave (CW) oximeters (Sensmart Model X-100 Universal Oximetry System, INVOS 5100C, and OxyPrem v1...
November 1, 2016: Biomedical Optics Express
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