Read by QxMD icon Read


Aida Niñerola-Baizán, Judith Gallego, Albert Cot, Pablo Aguiar, Francisco Lomeña, Javier Pavía, Domenec Ros
The aim of this work was to obtain a set of parameters to be applied in [123I]FP-CIT SPECT reconstruction in order to minimize the error between standardized and true values of the Specific Uptake Ratio (SUR) in dopaminergic neurotransmission SPECT studies. To this end, Monte Carlo simulation was used to generate a database of 1,380 projection data-sets from 23 subjects, including normal cases and a variety of pathologies. Studies were reconstructed using Filtered Back Projection (FBP) with attenuation correction and Ordered Subset Expectation Maximization (OSEM) with correction for different degradations (attenuation, scatter and PSF)...
March 19, 2018: Physics in Medicine and Biology
Shelley HuaLei Zhang, Stephan E Maier, Lawrence P Panych
PURPOSE: Magnetic resonance spectroscopic imaging (MRSI), under low-spatial resolution settings, often suffers signal contamination from neighboring voxels due to ringing artifacts. Spatial localization can be improved by constraining the point-spread-function (PSF). Here the effectiveness of the two-dimensional PSF-Choice technique in providing improved spatial localization for MRSI is demonstrated. THEORY AND METHODS: The PSF-Choice technique constrains the PSF to a desired shape by manipulating the weighting of RF excitation pulse throughout phase-encode steps...
March 3, 2018: Journal of Magnetic Resonance
Xiangsheng Xie, Huichang Zhuang, Hexiang He, Xiaoqing Xu, Haowen Liang, Yikun Liu, Jianying Zhou
Human ability to visualize an image is usually hindered by optical scattering. Recent extensive studies have promoted imaging technique through turbid materials to a reality where color image can be restored behind scattering media in real time. The big challenge now is to recover objects in a large field of view with depth resolving ability. Based on the existing research results, we systematically study the physical relationship between speckles generated from objects at different planes. By manipulating a given single point spread function, depth-resolved imaging through a thin scattering medium can be extended beyond the original depth of field (DOF)...
March 15, 2018: Scientific Reports
Md Asaduzzaman Shishir, Md Al Mamun, Md Mahmuduzzaman Mian, Umme Tamanna Ferdous, Noor Jahan Akter, Rajia Sultana Suravi, Suvamoy Datta, Md Ehsanul Kabir
The scarcity of hygienic drinking water is a normal phenomenon in the coastal areas of Bangladesh due to the high salinity of ground water. The inhabitants of this locality, therefore, live on alternative supplies of water including rain-fed pond water, and rainwater with persistent complex microbial interactions therein, often contaminated with life-threatening pathogens. Hence, this study was aimed at analyzing the prevalence of Vibrio cholerae ( Vc ) in the alternative drinking waters of Mathbaria, a coastal subdistrict neighboring the Bay of Bengal, the efficacy of pond sand filter (PSF) and the co-association among Bacillus -like spore formers (Sf) and Vc ...
2018: Frontiers in Public Health
Qingkun Xie, Jing Wang, Yanru Jiang, Jian Liang, Enshi Qu, Liyong Ren
Suffering from the limited number aperture, a resolution higher than 0.5λ cannot be obtained in conventional far-field optical imaging systems. Recently, research of the optical super-oscillation lens (SOL) has been demonstrated to realize sub-diffractive focusing in both theory and practice successfully. Nevertheless, these systems usually have characteristics of a localized field of view and low-intensity focal spot surrounded by huge sidelobes, which profoundly restricts their application for super-resolution imaging...
March 1, 2018: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Trevor E Angell, Chirag M Vyas, Justine A Barletta, Edmund S Cibas, Nancy L Cho, Gerard M Doherty, Atul A Gawande, Brooke E Howitt, Jeffrey F Krane, Ellen Marqusee, Kyle C Strickland, Erik K Alexander, Francis D Moore, Matthew A Nehs
BACKGROUND: Diagnostic hemithyroidectomy (HT) is the most widely recommended surgical procedure for a nodule with indeterminate cytology; however, additional details may make initial total thyroidectomy (TT) preferable. We sought to identify patient-specific factors (PSFs) associated with initial TT in patients with indeterminate thyroid nodules. METHODS: Retrospective analysis of all patients with a thyroid nodule ≥ 1 cm and initial cytology of atypia of undetermined significance or suspicious for follicular neoplasm between 2012 and 2015 who underwent thyroidectomy...
March 8, 2018: Annals of Surgical Oncology
M C Carvalho, A C Veloni, K Genaro, M L Brandão
A single threatening experience may change the behavior of an animal in a long-lasting way and elicit generalized behavioral responses to a novel threatening situation that is unrelated to the original aversive experience. Electrical stimulation (ES) of the dorsal periaqueductal gray (dPAG) produces a range of defensive reactions, characterized by freezing, escape, and post-stimulation freezing (PSF). The latter reflects the processing of ascending aversive information to prosencephalic structures, including the central nucleus of the amygdala (CeA), which allows the animal to evaluate the consequences of the aversive situation...
February 2018: Neurobiology of Learning and Memory
Deep Bera, Shreyas B Raghunathan, Chao Chen, Zhao Chen, Michiel A P Pertijs, Martin D Verweij, Verya Daeichin, Hendrik J Vos, Antonius F W van der Steen, Nico De Jong, Johan Hans G Bosch
Until now, no matrix transducer has been realized for 3D transesophageal echocardiography (TEE) in pediatric patients. In 3D TEE with a matrix transducer, the biggest challenges are to connect a large number of elements to a standard ultrasound system, and to achieve a high volume rate (>200 Hz). To address these issues, we have recently developed a prototype miniaturized matrix transducer for pediatric patients with micro-beamforming and a small central transmitter. In this paper we propose two multiline parallel 3D beamforming techniques (µBF25 and µBF169) using the micro-beamformed datasets from 25 and 169 transmit events to achieve volume rates of 300 Hz and 44 Hz, respectively...
March 6, 2018: Physics in Medicine and Biology
David Goodenough, Josh Levy, Hildur Olafsdottir, Ingvi Olafsson
This paper describes Development of a Phantom for Tomosynthesis with Potential for Automated Analysis via the Cloud. Several studies are underway to investigate the effectiveness of Tomosynthesis Mammographic Image Screening, including the large TMIST project as funded by the National Cancer Institute The development of the phantom described in this paper follows initiatives from the FDA, the AAPM TG245 task group, and European Reference Organization (EUREF) for Quality Assured Breast Screening and Diagnostic Services Committee report noting, that no formal endorsement nor recommendation for use has been sought, or granted by any of these groups...
March 6, 2018: Journal of Applied Clinical Medical Physics
Takatsugu Okegawa, Naoki Ninomiya, Kazuki Masuda, Yu Nakamura, Mitsuhiro Tambo, Kikuo Nutahara
OBJECTIVE: We examined whether androgen receptor splice variant 7 (AR-V7) in circulating tumor cell(CTC)clusters can be used to predict survival in patients with bone metastatic castration resistant-prostate cancer (mCRPC) treated with abiraterone or enzalutamide. METHODS: We retrospectively enrolled 98 patients with CRPC on abiraterone or enzalutamide, and investigated the prognostic value of CTC cluster detection (+ v -) and AR-V7 detection (+ v -) using a CTC cluster detection - based AR-V7 mRNA assay...
March 5, 2018: Prostate
Andres Kaalep, Terez Sera, Sjoerd Rijnsdorp, Maqsood Yaqub, Anne Talsma, Martin A Lodge, Ronald Boellaard
PURPOSE: The objective of this study was to explore the feasibility of harmonising performance for PET/CT systems equipped with time-of-flight (ToF) and resolution modelling/point spread function (PSF) technologies. A second aim was producing a working prototype of new harmonising criteria with higher contrast recoveries than current EARL standards using various SUV metrics. METHODS: Four PET/CT systems with both ToF and PSF capabilities from three major vendors were used to acquire and reconstruct images of the NEMA NU2-2007 body phantom filled conforming EANM EARL guidelines...
March 2, 2018: European Journal of Nuclear Medicine and Molecular Imaging
R A Boyle, T W Dahl, C J Bjerrum, D E Canfield
Mixing of sediments by moving animals becomes apparent in the trace fossil record from about 550 million years ago (Ma), loosely overlapping with the tail end of the extreme carbonate carbon isotope δ13 Ccarbonate fluctuations that qualitatively distinguish the Proterozoic geochemical record from that of the Phanerozoic. These Precambrian-scale fluctuations in δ13 Ccarbonate (PSF-δ13 Ccarbonate ) remain enigmatic, due to their high amplitude and inclusion of global-scale negative δ13 Ccarbonate values, below anything attributable to mantle input...
March 2, 2018: Geobiology
Harish Ravishankar, Felicity Roddick, Dimuth Navaratna, Veeriah Jegatheesan
Microfiltration membranes having different blends of graphene-oxide (GO) (0-1 wt%) and Polysulfone (PSf) (15-20 wt%) were prepared using the classical non-solvent induced phase inversion process. The prepared membranes were characterised for their structural morphology, surface properties, mechanical strength, porosity and pure water flux. Based on the initial characterisation results, four membranes (15 wt% PSf, 15 wt% PSf + 0.25 wt% GO, 15 wt% PSf + 1 wt% GO and 20 wt% PSf + 1 wt% GO) were chosen for critical flux study, that was conducted using flux-step method in a lab scale MBR system...
February 26, 2018: Journal of Environmental Management
Kenji Masumoto, Jared Joerger, John A Mercer
BACKGROUND: Running with body weight support (BWS) has been used for physical fitness enhancement. Nevertheless, gait mechanics of running with BWS is not fully understood. RESEARCH QUESTION: We investigated influence of stride frequency manipulation on muscle activity during running at various BWS conditions. METHODS: Nineteen participants (23.8 ± 4.1 years) ran on a lower body positive pressure treadmill at their preferred speed and preferred stride frequency (PSF) for 0%BWS, 50%BWS, and 80%BWS conditions...
February 16, 2018: Gait & Posture
Chiaki Tominaga, Hiroki Azumi, Mitsunori Goto, Masaaki Taura, Noriyasu Homma, Issei Mori
Edge methods are predominantly used for modulation transfer function (MTF) measurements in computed tomography (CT) images reconstructed using iterative methods. However, edge methods employ a relatively large and distinct test object, which is intended to simulate relatively large and distinct clinical organs. If one wants to assess the image quality of a small low-contrast object that is visually indistinct against a noisy background, a small and indistinct test object is desired. Another concern is that information related to the signal amount is discarded during MTF measurements...
February 23, 2018: Radiological Physics and Technology
René Berlich, Sjoerd Stallinga
An approach for designing purely refractive optical elements that generate engineered, multi-order-helix point spread functions (PSFs) with large peak separation for passive, optical depth measurement is presented. The influence of aberrations on the PSF's rotation angle, which limits the depth retrieval accuracy, is studied numerically and analytically. It appears that only Zernike modes with an azimuthal index that is an integer multiple of the number of PSF peaks introduce PSF rotation, and hence depth estimation errors...
February 19, 2018: Optics Express
Sohaib Abdul Rehman, Alexander R Carr, Martin O Lenz, Steven F Lee, Kevin O'Holleran
Super-resolution techniques that localize single molecules in three dimensions through point spread function (PSF) engineering are very sensitive to aberrations and optical alignment. Here we show how double-helix point spread function is affected by such mis-alignment and aberration. Specifically, we demonstrate through simulation and experiment how misplacement of phase masks in infinity corrected systems is a common source of significant loss of accuracy. We also describe an optimal alignment and calibration procedure to correct for these errors...
February 19, 2018: Optics Express
Andrew Kulmatiski
Plant-soil feedbacks (PSFs) have gained attention for their potential role in explaining plant growth and invasion. While promising, most PSF research has measured plant monoculture growth on different soils in short-term, greenhouse experiments. Here, five soil types were conditioned by growing one native species, three non-native species, or a mixed plant community in different plots in a common-garden experiment. After 4 years, plants were removed and one native and one non-native plant community were planted into replicate plots of each soil type...
February 2018: Ecology and Evolution
A Khan, M Delargy
Post stroke fatigue (PSF) is a frequently reported symptom by stroke survivors undergoing rehabilitation. This cross sectional observational study was undertaken in a rehabilitation facility to look at its prevalence and relationship with various variables like personal factors, type of stroke, social context, hemispheric involvement on CT scan and mobility status. The results showed that PSF was present in 83% (25 out of 30) of the patients included in the study. No clear association could be established between PSF, social, radiological and functional characteristics...
December 18, 2017: Irish Medical Journal
Fiona Helen Barrack, James Scuffham, Sarah McQuaid
Whole body gamma camera images acquired after I-131 treatment for thyroid cancer can suffer from collimator septal penetration artefacts because of the high energy of the gamma photons. This results in the appearance of 'spoke' artefacts, emanating from regions of high activity concentration, caused by the non-isotropic attenuation of the collimator. Deconvolution has the potential to reduce such artefacts, by taking into account the non-Gaussian point-spread-function (PSF) of the system. A Richardson-Lucy deconvolution algorithm, with and without prior scatter-correction was tested as a method of reducing septal penetration in planar gamma camera images...
February 21, 2018: Physics in Medicine and Biology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"