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https://www.readbyqxmd.com/read/28926968/weakening-pin-bone-attachment-in-fish-fillets-using-high-intensity-focused-ultrasound
#1
Martin H Skjelvareid, Svein Kristian Stormo, Kristín Anna Þórarinsdóttir, Karsten Heia
High Intensity Focused Ultrasound (HIFU) can be used for the localized heating of biological tissue through the conversion of sound waves into heat. Although originally developed for human medicine, HIFU may also be used to weaken the attachment of pin bones in fish fillets to enable easier removal of such bones. This was shown in the present study, where a series of experiments were performed on HIFU phantoms and fillets of cod and salmon. In thin objects such as fish fillets, the heat is mainly dissipated at the surfaces...
September 18, 2017: Foods (Basel, Switzerland)
https://www.readbyqxmd.com/read/28926370/photon-counting-computed-tomography-for-vascular-imaging-of-the-head-and-neck-first-in-vivo-human-results
#2
Rolf Symons, Daniel S Reich, Mohammadhadi Bagheri, Tyler E Cork, Bernhard Krauss, Stefan Ulzheimer, Steffen Kappler, David A Bluemke, Amir Pourmorteza
PURPOSE: The purpose of this study was to evaluate image quality of a spectral photon-counting detector (PCD) computed tomography (CT) system for evaluation of major arteries of the head and neck compared with conventional single-energy CT scans using energy-integrating detectors (EIDs). METHODS: In this institutional review board-approved study, 16 asymptomatic subjects (7 men) provided informed consent and received both PCD and EID contrast-enhanced CT scans of the head and neck (mean age, 58 years; range, 46-75 years)...
September 18, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28926276/polypyrrole-coated-perfluorocarbon-nanoemulsions-as-a-sono-photoacoustic-contrast-agent
#3
David Shicheng Li, Soon Joon Yoon, Ivan Pelivanov, M Frenz, Matthew O'Donnell, Lilo D Pozzo
A new contrast agent for combined photoacoustic and ultrasound imaging is presented. It has a liquid perfluorocarbon (PFC) core of about 250 nm diameter coated by a 30 nm thin polypyrrole (PPy) doped polymer shell emulsion which represents a broadband absorber covering the visible and near-infrared ranges (peak optical extinction at 1050 nm). When exposed to a sufficiently high intensity optical or acoustic pulse, the droplets vaporize to form microbubbles providing a strong increase in imaging sensitivity and specificity...
September 19, 2017: Nano Letters
https://www.readbyqxmd.com/read/28926263/copper-sulfide-perfluorocarbon-nanodroplets-as-clinically-relevant-photoacoustic-ultrasound-imaging-agents
#4
Daniela Y Santiesteban, Diego S Dumani, Daniel Profili, Stanislav Y Emelianov
We have developed laser-activated perfluorocarbon nanodroplets containing copper sulfide nanoparticles (CuS NPs) for contrast-enhanced ultrasound and photoacoustic imaging. As potential clinical contrast agents, CuS NPs have favorable properties including biocompatibility, biodegradability and enhance contrast in photoacoustic images at clinically relevant depths. However, CuS NPs are not efficient optical absorbers when compared to plasmonic nanoparticles and therefore, contrast enhancement with CuS NPs is limited, requiring high concentrations to generate images with sufficient signal-to-noise ratio...
September 19, 2017: Nano Letters
https://www.readbyqxmd.com/read/28926200/dual-wavelength-assisted-thermal-hemostasis-for-treatment-of-benign-prostate-hyperplasia
#5
Jiuen Hwang, Hyejin Kim, Truong Van Gia, Jason Xuan, Thomas Hasenberg, Hyun Wook Kang
Laser treatment on a large size of prostate gland often encounters significant bleeding that can prolong the entire procedure and cause urinary complications. The current study investigates the feasibility of dual-wavelength (532 and 980 nm) application to achieve rapid hemostasis for 532-nm laser prostatectomy. Porcine kidney and bleeding phantom models were tested to quantify the degree of the irreversible tissue coagulation and to estimate the time for the complete hemostasis, respectively. The ex vivo kidney testing verifies that the dual-wavelength created up to 40% deeper and 25% wider coagulation regions than a single wavelength does...
September 19, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28925108/development-of-a-reliable-and-reproducible-phantom-manufacturing-method-using-silica-microspheres-in-silicone
#6
Charlotte Maughan Jones, Peter R Munro
Optically scattering phantoms composed of silica microspheres embedded in an optically clear silicone matrix were manufactured using a previously developed method. Multiple problems, such as sphere aggregation, adsorption to the cast, and silicone shrinkage, were, however, frequently encountered. Solutions to these problems were developed and an improved method, incorporating these solutions, is presented. The improved method offers excellent reliability and reproducibility for creating phantoms with uniform scattering coefficient...
September 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/28924572/stereovision-based-integrated-system-for-point-cloud-reconstruction-and-simulated-brain-shift-validation
#7
Xiaochen Yang, Logan W Clements, Ma Luo, Saramati Narasimhan, Reid C Thompson, Benoit M Dawant, Michael I Miga
Intraoperative soft tissue deformation, referred to as brain shift, compromises the application of current image-guided surgery navigation systems in neurosurgery. A computational model driven by sparse data has been proposed as a cost-effective method to compensate for cortical surface and volumetric displacements. We present a mock environment developed to acquire stereoimages from a tracked operating microscope and to reconstruct three-dimensional point clouds from these images. A reconstruction error of 1 mm is estimated by using a phantom with a known geometry and independently measured deformation extent...
July 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28924570/implementation-and-ct-sampling-characterization-of-a-third-generation-spect-ct-system-for-dedicated-breast-imaging
#8
Jainil P Shah, Steve D Mann, Randolph L McKinley, Martin P Tornai
Stand-alone cone beam computed tomography (CT) and single-photon emission computed tomography (SPECT) systems capable of complex acquisition trajectories have previously been developed for breast imaging. Fully three-dimensional (3-D) motions of SPECT systems provide views into the chest wall and throughout the entire volume. The polar tilting capability of the CBCT system has shown improvement in sampling close to the chest wall, while eliminating cone beam artifacts. Here, a single hybrid SPECT-CT system, with each individual modality capable of independently traversing complex trajectories around a common pendant breast volume, was developed...
July 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28922970/use-of-synchrotron-radiation-to-accurately-assess-cross-sectional-area-reduction-of-the-aortic-branch-ostia-caused-by-suprarenal-stent-wires
#9
Zhonghua Sun, Curtise K C Ng
PURPOSE: To compare in vivo the use of synchrotron radiation to computed tomography angiography (CTA) for the measurement of cross-sectional area (CSA) reduction of the aortic branch ostia caused by suprarenal stent-graft wires. METHODS: This study was performed with a Zenith stent-graft placed in a phantom of the human aorta to simulate treatment of abdominal aortic aneurysm. Synchrotron radiation scans were performed using beam energies between 40 and 100 keV and spatial resolution of 19...
September 1, 2017: Journal of Endovascular Therapy
https://www.readbyqxmd.com/read/28922946/temperature-simulation-of-microwave-ablation-based-on-improved-specific-absorption-rate-method-compared-to-phantom-measurements
#10
Hongjian Gao, Shuicai Wu, Xiaoru Wang, Rui Hu, Zhuhuang Zhou, Xuecong Sun
PURPOSE: To propose an improved specific absorption rate (SAR) computation method by incorporating a thermal conductivity item, develop mathematical simulation models based on the SAR, and enhance the accuracy of temperature simulation for 2450-MHz microwave fields. MATERIALS AND METHODS: Experimental data of 2450-MHz microwave antenna were obtained with a phantom and then new SAR equations were calculated according to Pennes bio-heat transfer equation. Next, the SAR equations were regarded as heating sources and SAR-derived temperature changes were simulated numerically; Finally, temperature measurement results were compared with simulation data to validate the accuracy of the new SAR method...
September 18, 2017: Computer Assisted Surgery (Abingdon, England)
https://www.readbyqxmd.com/read/28922941/taguchi-dynamic-analysis-application-to-computer-tomography-number-mass-density-linear-dependence-optimization
#11
Kuo Hsun-Nan, Yi Juei-En, Chen Chia-Hui, Pan Lung-Fa, Pan Lung-Kwang
The Taguchi dynamic analysis was applied to optimize the linear dependence between computer tomography (CT) number and mass density. The Taguchi unique L18(2(1) × 3(5)) orthogonal array was utilized in the dynamic analysis of a commercial Catphan 600 phantom with CTP 404 module, in order to optimize eighteen combinations of six factors controlling the CT simulator operation, i.e. scan time, kVp, mA, field of view (FOV), slice thickness, and imaging processing algorithm. Each factor being assigned two or three different levels made it possible to organize the required number of combinations (18)...
September 18, 2017: Computer Assisted Surgery (Abingdon, England)
https://www.readbyqxmd.com/read/28922140/a-point-kernel-algorithm-for-microbeam-radiation-therapy
#12
Charlotte Debus, Uwe Oelfke, Stefan Bartzsch
Microbeam Radiation Therapy (MRT) is a treatment approach in radiation therapy where the treatment field is spatially fractionated into arrays of a few tens of micrometre wide planar beams of unusually high peak doses separated by low dose regions of several hundred micrometre width. In preclinical studies, this treatment approach has proven to spare normal tissue more effectively than conventional radiation therapy, while being equally efficient in tumour control. So far dose calculations in MRT, a prerequisite for future clinical applications are based on Monte Carlo simulations...
September 18, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28922117/magnetic-resonance-mediated-radiofrequency-ablation
#13
Yik-Kiong Hue, Alexander R Guimaraes, Ouri Cohen, Erez Nevo, Abraham Roth, Jerome L Ackerman, Jerome L Ackerman
OBJECTIVE: To introduce magnetic resonance mediated radiofrequency ablation (MR-RFA), in which the MRI scanner uniquely serves both diagnostic and therapeutic roles. In MR-RFA scanner-induced RF heating is channeled to the ablation site via a Larmor frequency RF pickup device and needle system, and controlled via the pulse sequence. METHODS: MR-RFA was evaluated with simulation of electric and magnetic fields to predict the increase in local specific-absorption-rate (SAR)...
September 18, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28921910/100-days-with-scans-of-the-same-catphan-phantom-on-the-same-ct-scanner
#14
Ellen Husby, Elisabeth D Svendsen, Hilde K Andersen, Anne Catrine T Martinsen
Quality control (QC) of CT scanners is important to evaluate image quality and radiation dose. Different QC phantoms for testing image quality parameters on CT are commercially available, and Catphan phantoms are widely used for this purpose. More data from measured image quality parameters on CT are necessary to assess test methods, tolerance levels, and test frequencies. The aim of this study was to evaluate the stability of essential image quality parameters for axial and helical scans on one CT scanner over time...
September 18, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28921655/fast-dynamic-ventilation-mri-of-hyperpolarized-129-xe-using-spiral-imaging
#15
Ozkan Doganay, Tahreema N Matin, Anthony Mcintyre, Brian Burns, Rolf F Schulte, Fergus V Gleeson, Daniel Bulte
PURPOSE: To develop and optimize a rapid dynamic hyperpolarized (129) Xe ventilation (DXeV) MRI protocol and investigate the feasibility of capturing pulmonary signal-time curves in human lungs. THEORY AND METHODS: Spiral k-space trajectories were designed with the number of interleaves Nint  = 1, 2, 4, and 8 corresponding to voxel sizes of 8 mm, 5 mm, 4 mm, and 2.5 mm, respectively, for field of view = 15 cm. DXeV images were acquired from a gas-flow phantom to investigate the ability of Nint  = 1, 2, 4, and 8 to capture signal-time curves...
September 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28921564/machine-specific-quality-assurance-procedure-for-stereotactic-treatments-with-dynamic-couch-rotations
#16
Byron Wilson, Ermias Gete
OBJECTIVE: We present a method in which the treatment couch's accuracy is measured using the electronic portal imaging device (EPID) and a phantom of our own construction. Using this phantom, we were able to quantify the treatment couch walkout, and the rotation angle accuracy for both static and dynamic couch treatments. These measurements were used to provide an accurate measure of the treatment couch isocentre as well as to verify the couch rotation angle recorded in the trajectory log...
September 18, 2017: Medical Physics
https://www.readbyqxmd.com/read/28921474/origins-of-phantom-limb-pain
#17
Damien P Kuffler
Phantom limb pain (PLP) is a chronic neuropathic pain occurring in 45-85% of patients who undergo major amputations of the upper and lower extremities. Chronic pain is physically and mentally debilitating, affecting an individual's potential for self-care and the performance of daily living activities essential for personal and economic independence. In addition, chronic pain may lead to depression and feelings of hopelessness. A National Center for Biotechnology Information study found that in the USA alone, the annual cost of dealing with neuropathic pain is more than $600 billion, with an estimated 20 million people in the USA suffering this condition...
September 18, 2017: Molecular Neurobiology
https://www.readbyqxmd.com/read/28921418/coping-with-phantom-limb-pain
#18
Damien P Kuffler
Phantom limb pain is a chronic neuropathic pain that develops in 45-85% of patients who undergo major amputations of the upper and lower extremities and appears predominantly during two time frames following an amputation: the first month and later about 1 year. Although in most patients the frequency and intensity of pain diminish over time, severe pain persists in about 5-10%. It has been proposed that factors in both the peripheral and central nervous systems play major roles in triggering the development and maintenance of pain associated with extremity amputations...
September 18, 2017: Molecular Neurobiology
https://www.readbyqxmd.com/read/28921404/effectiveness-of-a-new-lead-shielding-device-and-additional-filter-for-reducing-staff-and-patient-radiation-exposure-during-videofluoroscopic-swallowing-study-using-a-human-phantom
#19
Yoshiaki Morishima, Koichi Chida, Yoshikazu Muroya, Yoshiya Utsumi
Interventional radiology procedures often involve lengthy exposure to fluoroscopy-derived radiation. We therefore devised a videofluoroscopic swallowing study (VFSS) procedure using a human phantom that proved to protect the patient and physician by reducing the radiation dose. We evaluated a new lead-shielding device and separately attached additional filters (1.0-, 2.0-, and 3.0-mm Al filters and a 0.5-mm Cu filter) during VFSS to reduce the patient's entrance skin dose (ESD). A monitor attached to the human phantom's neck measured the ESD...
September 18, 2017: Dysphagia
https://www.readbyqxmd.com/read/28920898/hybrid-pre-log-and-post-log-image-reconstruction-for-computed-tomography
#20
Guobao Wang, Jian Zhou, Zhou Yu, Wenli Wang, Jinyi Qi
Tomographic image reconstruction for low-dose CT is increasingly challenging as dose continues to reduce in clinical applications. Pre-log domain methods and post-log domain methods have been proposed individually and each method has its own disadvantage. While having the potential to improve image quality for low-dose data by using an accurate imaging model, pre-log domain methods suffer slow convergence in practice due to the nonlinear transformation from the image to measurements. In contrast, post-log domain methods have fast convergence speed but the resulting image quality is suboptimal for low-count CT data because the log transformation is extremely unreliable for low-count measurements and undefined for negative values...
September 13, 2017: IEEE Transactions on Medical Imaging
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