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https://www.readbyqxmd.com/read/28535414/gamma-radiography-and-tomography-with-a-ccd-camera-and-co-60-source
#1
Robert Adams, Robert Zboray
Gamma imaging using a relatively low strength 5.8mCi laboratory Co-60 source and a CsI(Tl) scintillator screen read out by a CCD camera was investigated. A simple model was used to estimate the effective count rate, which was verified with experiments. Radiography and tomography of phantoms were used to determine the test setup spatial resolution of about 1.3-2.5mm. Exposure times were on the order of a couple minutes per radiograph. These tests demonstrate the value of the count rate model and the feasibility of the setup as a simple and low-cost solution for gamma imaging cases where acquisition time is flexible and resolution requirements are moderate...
May 17, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28534769/a-systematic-investigation-of-lateral-estimation-using-various-interpolation-approaches-in-conventional-ultrasound-imaging
#2
Zhi Liu, Chengwu Huang, Jianwen Luo
Accurate lateral displacement and strain estimat- ion is critical for some applications of elasticity imaging. Typically, motion estimation in the lateral direction is challenging because of low sampling frequency and lack of phase information in conventional ultrasound imaging. Several approaches have been proposed to improve the performance of lateral estimation, such as lateral interpolation on the RF signals (Interp_RF), lateral interpolation on the cross-correlation function (Interp_CCF) and lateral interpolation on both the RF signals and cross-correlation function (Interp_Both)...
May 17, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28534200/atrophy-of-calf-muscles-by-unloading-results-in-an-increase-of-tissue-sodium-concentration-and-fat-fraction-decrease-a-23-na-mri-physiology-study
#3
D A Gerlach, K Schopen, P Linz, B Johannes, J Titze, J Zange, J Rittweger
PURPOSE: (23)Na MRI demonstrated increased tissue sodium concentrations in a number of pathologies. Acute atrophy results in muscle fibre volume shrinking that may result in a relative increase of extracellular volume and might affect sodium concentration. Thus, we hypothesized that local unloading of the calf muscles would lead to a decrease in muscle volume and an increase in muscle tissue sodium concentration. METHOD: One lower leg of 12 healthy male subjects was submitted to a 60 day long period of unloading using the Hephaistos orthosis, while the other leg served as control...
May 22, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28533804/the-use-of-trans-applicator-intracavitary-ultrasonography-in-brachytherapy-for-cervical-cancer-phantom-study-of-a-novel-approach-to-3d-image-guided-brachytherapy
#4
Tomoaki Tamaki, Kazunori Miyaura, Toshihiro Murakami, Yu Kumazaki, Yoshiyuki Suzuki, Takashi Nakano, Shingo Kato
PURPOSE: To assess the feasibility of applying trans-applicator intracavitary ultrasonography to image-guided brachytherapy for cervical cancer. MATERIAL AND METHODS: For this experiment, a phantom was created and included a polyethylene tube, intended to simulate a tandem applicator, which was inserted into chicken meat and embedded in agar, along with magnetic resonance imaging (MRI)-compatible ovoid applicators. Three-dimensional images of the phantom were obtained using computed tomography (CT), MRI (T2-weighted), and intracavitary ultrasonography sectional images acquired at 1 mm slice intervals...
April 2017: Journal of Contemporary Brachytherapy
https://www.readbyqxmd.com/read/28533738/genetics-of-tinnitus-still-in-its-infancy
#5
REVIEW
Barbara Vona, Indrajit Nanda, Wafaa Shehata-Dieler, Thomas Haaf
Tinnitus is the perception of a phantom sound that affects between 10 and 15% of the general population. Despite this considerable prevalence, treatments for tinnitus are presently lacking. Tinnitus exhibits a diverse array of recognized risk factors and extreme clinical heterogeneity. Furthermore, it can involve an unknown number of auditory and non-auditory networks and molecular pathways. This complex combination has hampered advancements in the field. The identification of specific genetic factors has been at the forefront of several research investigations in the past decade...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28532617/first-french-experiences-of-total-body-irradiations-using-helical-tomotherapy-%C3%A2
#6
R Sun, X Cuenca, R Itti, S Nguyen Quoc, J-P Vernant, J-J Mazeron, C Jenny, M Chea
PURPOSE: Dynamic conformal radiotherapy with helical TomoTherapy(®) (HT) offers a more quantitative paradigm for total body irradiation. Treatment planning, delivery, dose verification of the first French experiences of total body irradiation using helical TomoTherapy(®) are presented. MATERIALS AND METHODS: Patients planned for total body irradiation at our institution from February 2012 to May 2013 were reported. Total body irradiation consisted in a single fraction of 2Gy...
May 19, 2017: Cancer Radiothérapie: Journal de la Société Française de Radiothérapie Oncologique
https://www.readbyqxmd.com/read/28532606/verifying-tumor-position-during-stereotactic-body-radiation-therapy-delivery-using-limited-arc-cone-beam-computed-tomography-imaging
#7
Colien Hazelaar, Max Dahele, Stefan Scheib, Ben J Slotman, Wilko F A R Verbakel
BACKGROUND AND PURPOSE: Proof of tumor position during stereotactic body radiotherapy (SBRT) delivery is desirable. We investigated if cone-beam CT (CBCT) scans reconstructed from (collimated) fluoroscopic kV images acquired during irradiation could show the dominant tumor position. MATERIALS AND METHODS: Full-arc CBCT scans were reconstructed using FDK filtered back projection from 38kV fluoroscopy datasets (16 patients) continuously acquired during volumetric modulated spine SBRT...
May 19, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28531979/synthesis-and-characterization-of-glycyrrhizic-acid-coated-iron-oxide-nanoparticles-for-hyperthermia-applications
#8
Mostafa Saeedi, Omid Vahidi, Shahin Bonakdar
In the present study, iron oxide magnetic nanoparticles (IONPs) were synthesized using the oxidative precipitation method for biomedical applications. Glycyrrhizic acid (GA) extracted from the roots of licorice plant was used as the coating agent for the synthesized nanoparticles (GAIONPs). The crystal phase, morphology and size were investigated by XRD, FE-SEM and TEM. The saturation magnetization (ms) value of the nanoparticles was measured by VSM indicating lowered ms of the GAIONPs with respect to that of the IONPs due to the presence of GA...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28531093/development-of-a-low-energy-x-ray-camera-for-the-imaging-of-secondary-electron-bremsstrahlung-x-ray-emitted-during-proton-irradiation-for-range-estimation
#9
Koki Ando, Mitsutaka Yamaguchi, Seiichi Yamamoto, Toshiyuki Toshito, Naoki Kawachi
Imaging of secondary electron bremsstrahlung x-ray emitted during proton irradiation is a possible method for measurement of the proton beam distribution in phantom. However, it is not clear that the method is used for range estimation of protons. For this purpose, we developed a low-energy x-ray camera and conducted imaging of the bremsstrahlung x-ray produced during irradiation of proton beams. We used a 20 mm  ×  20 mm  ×  1 mm finely grooved GAGG scintillator that was optically coupled to a one-inch square high quantum efficiency (HQE)-type position-sensitive photomultiplier tube to form an imaging detector...
May 22, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28530786/morphine-for-chronic-neuropathic-pain-in-adults
#10
REVIEW
Tess E Cooper, Junqiao Chen, Philip J Wiffen, Sheena Derry, Daniel B Carr, Dominic Aldington, Peter Cole, R Andrew Moore
BACKGROUND: Neuropathic pain, which is caused by a lesion or disease affecting the somatosensory system, may be central or peripheral in origin. Neuropathic pain often includes symptoms such as burning or shooting sensations, abnormal sensitivity to normally painless stimuli, or an increased sensitivity to normally painful stimuli. Neuropathic pain is a common symptom in many diseases of the nervous system. Opioid drugs, including morphine, are commonly used to treat neuropathic pain...
May 22, 2017: Cochrane Database of Systematic Reviews
https://www.readbyqxmd.com/read/28530209/reproducible-3d-printed-head-tanks-for-electrical-impedance-tomography-with-realistic-shape-and-conductivity-distribution
#11
James Avery, Kirill Aristovich, Barney Low, David Holder
OBJECTIVE: Electrical impedance tomography (EIT) has many promising applications in brain injury monitoring. To evaluate both instrumentation and reconstruction algorithms, experiments are first performed in head tanks. Existing methods, whilst accurate, produce a discontinuous conductivity, and are often made by hand, making it hard for other researchers to replicate. APPROACH: We have developed a method for constructing head tanks directly in a 3D printer. Conductivity was controlled through perforations in the skull surface, which allow for saline to pass through...
May 22, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28530205/phantom-experiments-using-soft-prior-regularization-eit-for-breast-cancer-imaging
#12
Ethan K Murphy, Aditya Mahara, Xiaotian Wu, Ryan J Halter
OBJECTIVE: A soft-prior regularization (SR) electrical impedance tomography (EIT) technique for breast cancer imaging is described, which shows an ability to accurately reconstruct tumor/inclusion conductivity values within a dense breast model investigated using a cylindrical and a breast-shaped tank. APPROACH: The SR-EIT method relies on knowing the spatial location of a suspicious lesion initially detected from a second imaging modality. Standard approaches (using Laplace smoothing and total variation regularization) without prior structural information are unable to accurately reconstruct or detect the tumors...
June 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28529464/trap-design-and-construction-for-high-power-multinuclear-magnetic-resonance-experiments
#13
Joseph V Rispoli, Ivan E Dimitrov, Sergey Cheshkov, Craig Malloy, Steven M Wright, Mary P McDougall
Performing multinuclear experiments requires one or more radiofrequency (RF) coils operating at both the proton and second-nucleus frequencies; however, inductive coupling between coils must be mitigated to retain proton sensitivity and coil tuning stability. The inclusion of trap circuits simplifies placement of multinuclear RF coils while maintaining inter-element isolation. Of the commonly investigated non-proton nuclei, perhaps the most technically demanding is carbon-13, particularly when applying a proton decoupling scheme to improve the resulting spectra...
October 2016: Concepts in Magnetic Resonance. Part B, Magnetic Resonance Engineering
https://www.readbyqxmd.com/read/28529251/image-quality-and-clinical-usefulness-of-ray-summation-image-reconstructed-from-ct-data-compared-with-digital-radiography
#14
Shogo Suzuki, Katsuhiro Ichikawa, Shigeru Tamaki
Ray-summation (raysum) images reconstructed from computed tomography (CT) volume data resemble digital radiography (DR) images. Therefore, they have a potential to be used instead of DR images.The aim of this study was to compare the physical image quality evaluated by signal-difference-to-noise ratio (SDNR) and clinical usefulness between raysum and DR images. We employed an oval water phantom simulating adult abdomen for image quality measurement. Raysum images were reconstructed from CT volume data using an assumed x-ray quality of 70 keV...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28529250/impact-of-jaw-position-accuracy-on-dose-variation-in-volumetric-modulated-arc-therapy-using-jaw-tracking
#15
Fumiyasu Matsubayashi, Yuki Koizumi, Ryo Takahashi, Minoru Yoshioka, Tomoharu Sato
The technique of jaw tracking can be used in volumetric modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT). In this technique, jaw tracks apertures of the multi leaf collimator (MLC) during irradiation. It is reported that dose variation is occurred by the changing accuracy of MLC position in VMAT and IMRT. Though jaw moves dynamically in the irradiation by using this technique, the influence of the jaw position accuracy on dose variation is not examined. The purpose of this study is to verify the influence of jaw position accuracy on dose variation in VMAT using jaw tracking...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28528720/in%C3%A2-vivo-dosimetry-in-gynecological-applications-a-feasibility-study
#16
Marion P R Van Gellekom, Richard A M Canters, Frank J W M Dankers, Agnes Loopstra, Elzbieta M van der Steen-Banasik, Marie A D Haverkort
PURPOSE: To investigate the feasibility of in vivo dosimetry using microMOSFET dosimeters in patients treated with brachytherapy using two types of gynecological applicators. METHODS AND MATERIALS: In this study, a microMOSFET was placed in an empty needle of an Utrecht Interstitial Fletcher applicator or MUPIT (Martinez Universal Perineal Interstitial Template) applicator for independent verification of treatment delivery. Measurements were performed in 10 patients, with one to three microMOSFETs per applicator and repeated for one to four fractions, resulting in 50 in vivo measurements...
May 18, 2017: Brachytherapy
https://www.readbyqxmd.com/read/28527792/3d-cmro2-mapping-in-human-brain-with-direct-17-o-mri-comparison-of-conventional-and-proton-constrained-reconstructions
#17
Dmitry Kurzhunov, Robert Borowiak, Marco Reisert, Axel Joachim Krafft, Ali Caglar Özen, Michael Bock
Oxygen metabolism is altered in brain tumor regions and is quantified by the cerebral metabolic rate of oxygen consumption (CMRO2). Direct dynamic (17)O MRI with inhalation of isotopically enriched (17)O2 gas can be used to quantify CMRO2; however, pixel-wise CMRO2 quantification in human brain is challenging due to low natural abundance of (17)O isotope and, thus, the low signal-to-noise ratio (SNR) of (17)O MR images. To test the feasibility CMRO2 mapping at a clinical 3 T MRI system, a new iterative reconstruction was proposed, which uses the edge information contained in a co-registered (1)H gradient image to construct a non-homogeneous anisotropic diffusion (AD) filter...
May 17, 2017: NeuroImage
https://www.readbyqxmd.com/read/28527605/analysis-of-gafchromic-ebt3-film-calibration-irradiated-with-gamma-rays-from-different-systems-gamma-knife-and-cobalt-60-unit
#18
Monsen Najafi, Ghazale Geraily, Alireza Shirazi, Mahbod Esfahani, Javad Teimouri
In recent years, Gafchromic films are used as an advanced instrument for dosimetry systems. The EBT3 films are a new generation of Gafchromic films. Our main interest is to compare the response of the EBT3 films exposed to gamma rays provided by the Theratron 780C as a conventional radiotherapy system and the Leksell Gamma Knife as a stereotactic radiotherapy system (SRS). Both systems use Cobalt-60 sources, thus using the same energy. However, other factors such as source-to-axis distance, number of sources, dose rate, direction of irradiation, shape of phantom, the field shape of radiation, and different scatter contribution may influence the calibration curve...
May 17, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28527025/pose-aware-c-arm-for-automatic-re-initialization-of-interventional-2d-3d-image-registration
#19
Javad Fotouhi, Bernhard Fuerst, Alex Johnson, Sing Chun Lee, Russell Taylor, Greg Osgood, Nassir Navab, Mehran Armand
PURPOSE: In minimally invasive interventions assisted by C-arm imaging, there is a demand to fuse the intra-interventional 2D C-arm image with pre-interventional 3D patient data to enable surgical guidance. The commonly used intensity-based 2D/3D registration has a limited capture range and is sensitive to initialization. We propose to utilize an opto/X-ray C-arm system which allows to maintain the registration during intervention by automating the re-initialization for the 2D/3D image registration...
May 19, 2017: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/28526430/combination-of-integrated-dynamic-shimming-and-readout-segmented-echo-planar-imaging-for-diffusion-weighted-mri-of-the-head-and-neck-region-at-3tesla
#20
Sven S Walter, Wei Liu, Alto Stemmer, Petros Martirosian, Konstantin Nikolaou, Mike Notohamiprodjo, Sergios Gatidis
PURPOSE: To evaluate the performance of combined integrated slice-by-slice shimming and readout-segmented EPI (irsEPI) for diffusion-weighted MR imaging (DWI) of the neck at 3Tesla. METHODS: This study was approved by the local ethics committee. An anthropometric phantom of the head/neck region incorporating compartments with different diffusivities was constructed. In vivo measurements were performed in 10 healthy volunteers. DWI of the phantom and volunteers was performed on a 3Tesla MR scanner using single shot EPI (sEPI), a prototype single shot EPI with integrated slice-by-slice shimming (iEPI), readout segmented EPI (rsEPI) and a prototype readout segmented EPI with integrated shimming irsEPI...
May 16, 2017: Magnetic Resonance Imaging
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