keyword
MENU ▼
Read by QxMD icon Read
search

PSF

keyword
https://www.readbyqxmd.com/read/28107576/non-invasive-anaesthetic-methods-for-dermatological-laser-procedures-a-systematic-review
#1
REVIEW
K Greveling, E P Prens, L Liu, M B A van Doorn
Pain is a common side-effect of dermatological laser procedures. Non-invasive anaesthetic drugs and anaesthetic procedures can be used to provide pain relief and increase patient satisfaction and treatment efficacy. However, it remains unclear which method provides the best pain relief. The objective of this systematic review was therefore to assess the efficacy and safety of non-invasive anaesthetic methods during dermatological laser procedures. A systematic literature search was conducted. Randomized and non-randomized controlled clinical trials (RCTs and CCTs) were included...
January 20, 2017: Journal of the European Academy of Dermatology and Venereology: JEADV
https://www.readbyqxmd.com/read/28102960/nine-degrees-of-freedom-flexmap-for-a-cone-beam-computed-tomography-imaging-device-with-independently-movable-source-and-detector
#2
Peter Keuschnigg, Daniel Kellner, Karl Fritscher, Andrea Zechner, Ulrich Mayer, Philipp Huber, Felix Sedlmayer, Heinz Deutschmann, Philipp Steininger
PURPOSE: Couch-mounted cone-beam computed tomography (CBCT) imaging devices with independently rotatable x-ray source and flat-panel detector arms for acquisitions of arbitrary regions of interest (ROI) have recently been introduced in image-guided radiotherapy (IGRT). This work analyzes mechanical limitations and gravity-induced effects influencing the geometric accuracy of images acquired with arbitrary angular constellations of source and detector in nonisocentric trajectories, which is considered essential for IGRT...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28099660/socioeconomic-hygienic-and-sanitation-factors-in-reducing-diarrhea-in-the-amazon
#3
Katiuscia Shirota Imada, Thiago Santos de Araújo, Pascoal Torres Muniz, Valter Lúcio de Pádua
OBJECTIVE: To analyze the contributions of the socioeconomic, hygienic, and sanitation improvements in reducing the prevalence of diarrhea in a city of the Amazon. METHODS: In this population-based cross-sectional study, we analyzed data from surveys conducted in the city of Jordão, Acre. In 2005 and 2012, these surveys evaluated, respectively, 466 and 826 children under five years old. Questionnaires were applied on the socioeconomic conditions, construction of houses, food and hygienic habits, and environmental sanitation...
December 22, 2016: Revista de Saúde Pública
https://www.readbyqxmd.com/read/28092274/power-profiles-and-in-vitro-optical-quality-of-scleral-contact-lenses-effect-of-the-aperture-and-power
#4
Alberto Domínguez-Vicent, Jose Juan Esteve-Taboada, Alberto Recchioni
OBJECTIVE: To assess the power profile and in vitro optical quality of scleral contact lenses with different powers as a function of the optical aperture. METHODS: The mini and semiscleral contact lenses (Procornea) were measured for five powers per design. The NIMO TR-1504 (Lambda-X) was used to assess the power profile and Zernike coefficients of each contact lens. Ten measurements per lens were taken at 3- and 6-mm apertures. Furthermore, the optical quality of each lens was described in Zernike coefficients, modulation transfer function, and point spread function (PSF)...
January 13, 2017: Eye & Contact Lens
https://www.readbyqxmd.com/read/28091957/point-spread-function-reconstructed-pet-images-of-sub-centimeter-lesions-are-not-quantitative
#5
O L Munk, L P Tolbod, S B Hansen, T V Bogsrud
BACKGROUND: PET image reconstruction methods include modeling of resolution degrading phenomena, often referred to as point-spread function (PSF) reconstruction. The aim of this study was to develop a clinically relevant phantom and characterize the reproducibility and accuracy of high-resolution PSF reconstructed images of small lesions, which is a prerequisite for using PET in the prediction and evaluation of responses to treatment. Sets of small homogeneous (18)F-spheres (range 3-12 mm diameter, relevant for small lesions and lymph nodes) were suspended and covered by a (11)C-silicone, which provided a scattering medium and a varying sphere-to-background ratio...
December 2017: EJNMMI Physics
https://www.readbyqxmd.com/read/28087232/comparison-of-medial-malleolar-fracture-healing-at-8%C3%A2-weeks-after-open-reduction-internal-fixation-versus-percutaneous-fixation-a%C3%A2-retrospective-cohort-study
#6
Glenn M Weinraub, Patrick Levine, Eric Shi, Aarron Flowers
Unstable medial malleolar fractures are treated with either standard open reduction internal fixation (ORIF) or a percutaneous approach. The percutaneous approach avoids the potentially excessive soft tissue dissection associated with an open approach but can also result in inadequate anatomic reduction. No studies have compared the incidence of radiographic healing of medial malleolar fractures between an open approach and percutaneous fixation. A retrospective comparative study was performed at a single institution across multiple sites...
January 10, 2017: Journal of Foot and Ankle Surgery: Official Publication of the American College of Foot and Ankle Surgeons
https://www.readbyqxmd.com/read/28072636/accelerated-discharge-protocol-for-posterior-spinal-fusion-patients-with-adolescent-idiopathic-scoliosis-decreases-hospital-postoperative-charges-22
#7
Austin E Sanders, Lindsay M Andras, Ted Sousa, Cathy Kissinger, Giovanni Cucchiaro, David L Skaggs
STUDY DESIGN: A retrospective study of consecutive patients. OBJECTIVE: The purpose of this study was to determine implementing an accelerated protocol could decrease our average hospital stay and what impact this had on postoperative pain management. SUMMARY OF BACKGROUND DATA: To our knowledge, no prior studies have reviewed the effect of an accelerated discharge protocol on postoperative pain control for adolescent idiopathic scoliosis (AIS) following posterior spinal fusion...
January 15, 2017: Spine
https://www.readbyqxmd.com/read/28065851/high-resolution-distortion-free-diffusion-imaging-using-hybrid-spin-warp-and-echo-planar-psf-encoding-approach
#8
Myung-Ho In, Oleg Posnansky, Oliver Speck
High-resolution diffusion-weighted imaging (DWI) has great potential to provide unique information about tissue microstructure in-vivo. Although single-shot echo-planar imaging (EPI) is a most popular tool for DWI, its application for high-resolution DWI is limited due to T2* blurring and susceptibility- and eddy-current-induced geometric distortions, especially at ultra-high field (UHF) such as 7T. In this study, we adapt a hybrid spin-warp and echo-planar encoding strategy inspired by point spread function (PSF) mapping and optimize it for high-resolution and distortion-free diffusion imaging applications...
January 5, 2017: NeuroImage
https://www.readbyqxmd.com/read/28060179/uniplanar-versus-fixed-pedicle-screws-in-the-correction-of-thoracic-kyphosis-in-the-treatment-of-adolescent-idiopathic-scoliosis-ais
#9
Siddharth A Badve, Ryan C Goodwin, David Gurd, Thomas Kuivila, Swamy Kurra, William F Lavelle
BACKGROUND: The aim of surgical treatment of scoliosis is to obtain fusion of the spinal column, balanced in the coronal and sagittal planes. Great success has been attained with coronal correction; however, the sagittal profile has received less attention, resulting in little correction of sagittal plane alignment. The purpose of this study was to compare uniplanar and fixed pedicle screws in the correction of the thoracic sagittal alignment in the treatment of adolescent idiopathic scoliosis (AIS)...
January 5, 2017: Journal of Pediatric Orthopedics
https://www.readbyqxmd.com/read/28059149/volumetric-light-field-encryption-at-the-microscopic-scale
#10
Haoyu Li, Changliang Guo, Inbarasan Muniraj, Bryce C Schroeder, John T Sheridan, Shu Jia
We report a light-field based method that allows the optical encryption of three-dimensional (3D) volumetric information at the microscopic scale in a single 2D light-field image. The system consists of a microlens array and an array of random phase/amplitude masks. The method utilizes a wave optics model to account for the dominant diffraction effect at this new scale, and the system point-spread function (PSF) serves as the key for encryption and decryption. We successfully developed and demonstrated a deconvolution algorithm to retrieve both spatially multiplexed discrete data and continuous volumetric data from 2D light-field images...
January 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28054272/enhanced-bacterial-affinity-of-pvdf-membrane-its-application-as-improved-sea-water-sampling-tool-for-environmental-monitoring
#11
Sweta Binod Kumar, Preeti Sharnagat, Paramita Manna, Amit Bhattacharya, Soumya Haldar
Isolation of diversified bacteria from seawater is a major challenge in the field of environmental microbiology. In the present study, an attempt has been made to select specific membrane with improved property of attaching diversified bacteria. Initially, different concentrations (15, 18, and 20% W/W) of polysulfone (PSF) were used to check their affinity for the attachment of selected gram-positive (Bacillus subtilis) and gram-negative (Escherichia coli) bacteria. Among these, 20% W/W PSF showed maximum attachment...
January 5, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28048546/su-f-t-367-using-primo-a-penelope-based-software-to-improve-the-small-field-dosimetry-of-linear-accelerators
#12
H Benmakhlouf, L Brualla, P Andreo, J Sempau
PURPOSE: To calculate output correction factors for Varian Clinac 2100iX beams for seven small field detectors and use the values to determine the small field output factors for the linacs at Karolinska university hospital. METHODS: Phase space files (psf) for square fields between 0.25cm and 10cm were calculated using the PENELOPE-based PRIMO software. The linac MC-model was tuned by comparing PRIMO-estimated and experimentally determined depth doses and lateral dose-profiles for 40cmx40cm fields...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048447/su-g-iep3-08-image-reconstruction-for-scanning-imaging-system-based-on-shape-modulated-point-spreading-function
#13
Ruixing Wang, L V Yang, Kele Xu, Li Zhu
PURPOSE: Deconvolution is a widely used tool in the field of image reconstruction algorithm when the linear imaging system has been blurred by the imperfect system transfer function. However, due to the nature of Gaussian-liked distribution for point spread function (PSF), the components with coherent high frequency in the image are hard to restored in most of the previous scanning imaging system, even the relatively accurate PSF is acquired. We propose a novel method for deconvolution of images which are obtained by using shape-modulated PSF...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048001/su-f-t-66-characteristics-of-electron-beams-from-varian-trubeam
#14
A Dimofte, C Kennedy, T Zhu
PURPOSE: The purpose of this study was to compare the electron beam data between Truebeam and 2300ix Varian accelerators for percent depth dose for broad beam and small circular cutouts, cone factors, head scatter factor as a function of cone size and SSD, phantom scatter factor, blocking factor, distance factor and virtual source position. METHODS: Measurements were performed for Truebeam and 2300ix Varian accelerators. The main energies used were: 6, 9, 12, 16 and 20 MeV...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047850/we-de-207b-08-towards-standardization-of-x-ray-filters-in-digital-mammography-enabled-breast-tomosynthesis-systems
#15
S Shrestha, S Vedantham, A Karellas
PURPOSE: In digital breast tomosynthesis (DBT) systems capable of digital mammography (DM), Al filters are used during DBT and K-edge filters during DM. The potential for standardizing the x-ray filters with Al, instead of K-edge filters, was investigated with intent to reduce exposure duration and to promote a simpler system design. METHODS: Analytical computations of the half-value thickness (HVT) and the photon fluence per mAs (photons/mm2/mAs) for K-edge filters (50µm Rh; 50µm Ag) were compared with Al filters of varying thickness...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047403/su-f-j-224-impact-of-4d-pet-ct-on-percist-classification-of-lung-and-liver-metastases-in-nslc-and-colorectal-cancer
#16
J Meier, B Lopez, O Mawlawi
PURPOSE: To quantify the impact of 4D PET/CT on PERCIST metrics in lung and liver tumors in NSCLC and colorectal cancer patients. METHODS: 32 patients presenting lung or liver tumors of 1-3 cm size affected by respiratory motion were scanned on a GE Discovery 690 PET/CT. The bed position with lesion(s) affected by motion was acquired in a 12 minute PET LIST mode and unlisted into 8 bins with respiratory gating. Three different CT maps were used for attenuation correction: a clinical helical CT (CT_clin), an average CT (CT_ave), and an 8-phase 4D CINE CT (CT_cine)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047365/mo-fg-campus-iep1-01-alternative-k-edge-filters-for-low-energy-image-acquisition-in-contrast-enhanced-spectral-mammography
#17
S Shrestha, S Vedantham, A Karellas
PURPOSE: In Contrast Enhanced Spectral Mammography (CESM), Rh filter is often used during low-energy image acquisition. The potential for using Ag, In and Sn filters, which exhibit K-edge closer to, and just below that of Iodine, instead of the Rh filter, was investigated for the low-energy image acquisition. METHODS: Analytical computations of the half-value thickness (HVT) and the photon fluence per mAs (photons/mm2/mAs) for 50µm Rh were compared with other potential K-edge filters (Ag, In and Sn), all with K-absorption edge below that of Iodine...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047248/tu-fg-209-01-a-model-of-noise-anisotropy-in-amorphous-selenium-digital-detectors
#18
R Acciavatti, A Maidment
PURPOSE: One of the main advantages of amorphous selenium (a-Se) photoconductors is high spatial resolution. It has also been shown that the noise power spectra (NPS) is effectively white (frequency-independent) at various angles of x-ray incidence. One limitation of previous studies on NPS is that the effect of digitization has not been modeled. This work demonstrates that the NPS becomes colored (frequency-dependent) once digitization is taken into account. METHODS: A mammography system is modeled by tracing rays between the focal spot and the detector...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047217/we-ab-bra-08-correction-of-patient-motion-in-c-arm-cone-beam-ct-using-3d-2d-registration
#19
S Ouadah, M Jacobson, J W Stayman, T Ehtiati, J H Siewerdsen
PURPOSE: Intraoperative C-arm cone-beam CT (CBCT) is subject to artifacts arising from patient motion during the fairly long (∼5-20 s) scan times. We present a fiducial free method to mitigate motion artifacts using 3D-2D image registration that simultaneously corrects residual errors in geometric calibration. METHODS: A 3D-2D registration process was used to register each projection to DRRs computed from the 3D image by maximizing gradient orientation (GO) using the CMA-ES optimizer...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047099/we-de-207b-05-measuring-spatial-resolution-in-digital-breast-tomosynthesis-update-of-aapm-task-group-245
#20
D A Scaduto, M Goodsitt, H-P Chan, H Olafsdottir, M Das, E Fredenberg, W Geiser, D Goodenough, P Heid, Y-H Hu, B Liu, J Mainprize, I Reiser, R Van Engen, V Varchena, S Vecchio, S Glick, W Zhao
PURPOSE: Spatial resolution in digital breast tomosynthesis (DBT) is affected by inherent/binned detector resolution, oblique entry of x-rays, and focal spot size/motion; the limited angular range further limits spatial resolution in the depth-direction. While DBT is being widely adopted clinically, imaging performance metrics and quality control protocols have not been standardized. AAPM Task Group 245 on Tomosynthesis Quality Control has been formed to address this deficiency. METHODS: Methods of measuring spatial resolution are evaluated using two prototype quality control phantoms for DBT...
June 2016: Medical Physics
keyword
keyword
67214
1
2
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"