keyword
MENU ▼
Read by QxMD icon Read
search

PDD

keyword
https://www.readbyqxmd.com/read/28336006/influence-of-the-integral-quality-monitor-transmission-detector-on-high-energy-photon-beams-a-multi-centre-study
#1
Bozidar Casar, Marlies Pasler, Sonja Wegener, David Hoffman, Cinzia Talamonti, Jianguo Qian, Ignasi Mendez, Denis Brojan, Bruce Perrin, Martijn Kusters, Richard Canters, Stefania Pallotta, Primoz Peterlin
PURPOSE: The influence of the Integral Quality Monitor (IQM) transmission detector on photon beam properties was evaluated in a preclinical phase, using data from nine participating centres: (i) the change of beam quality (beam hardening), (ii) the influence on surface dose, and (iii) the attenuation of the IQM detector. METHODS: For 6 different nominal photon energies (4 standard, 2 FFF) and square field sizes from 1×1cm(2) to 20×20cm(2), the effect of IQM on beam quality was assessed from the PDD20,10 values obtained from the percentage dose depth (PDD) curves, measured with and without IQM in the beam path...
March 20, 2017: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/28331147/basic-study-on-visibility-and-water-equivalency-of-a-new-colorless-transparent-bolus-for-electron-radiotherapy
#2
Daiki Maruyama, Shinichi Yamazaki, Emi Honda, Eiji Suzuki, Kouji Hommatsu, Ryo Oshiba, Noboru Sato
Boluses used in electron radiotherapy need to have radiation field visibility and water equivalence. In this report, we have examined field visibility and water equivalence of a new colorless transparent bolus. We examined field visibility, water equivalence, and dose profile. Field visibility was evaluated by comparison to conventional bolus. Water equivalence was investigated by a measured fluence scaling factor. The dose profile was measured by using radiochromic film with the bolus and an ionization chamber in water...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28304294/long-term-cognitive-decline-in-dementia-with-lewy-bodies-in-a-large-multicenter-international-cohort
#3
Milica G Kramberger, Bjørn Auestad, Sara Garcia-Ptacek, Carla Abdelnour, Josep Garre Olmo, Zuzana Walker, Afina W Lemstra, Elisabet Londos, Frederic Blanc, Laura Bonanni, Ian McKeith, Bengt Winblad, Frank Jan de Jong, Flavio Nobili, Elka Stefanova, Maria Petrova, Cristian Falup-Pecurariu, Irena Rektorova, Sevasti Bostantjopoulou, Roberta Biundo, Daniel Weintraub, Dag Aarsland
BACKGROUND/OBJECTIVE: The aim of this study was to describe the rate and clinical predictors of cognitive decline in dementia with Lewy bodies (DLB), and compare the findings with Alzheimer's disease (AD) and Parkinson's disease dementia (PDD) patients. METHODS: Longitudinal scores for the Mini-Mental State Examination (MMSE) in 1,290 patients (835 DLB, 198 PDD, and 257 AD) were available from 18 centers with up to three years longitudinal data. Linear mixed effects analyses with appropriate covariates were used to model MMSE decline over time...
March 10, 2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28301249/investigation-of-different-infection-routes-of-parrot-bornavirus-in-cockatiels
#4
Julia Heckmann, Dirk Enderlein, Anne K Piepenbring, Sibylle Herzog, Ursula Heffels-Redmann, Sara Malberg, Christiane Herden, Michael Lierz
The aim of this study was to determine the natural infection route of parrot bornavirus (PaBV), the causative agent of proventricular dilatation disease (PDD) in psittacines. For this purpose, nine cockatiels ( Nymphicus hollandicus ) were inoculated orally, and nine cockatiels were inoculated intranasally, with a PaBV-4 isolate. To compare the results of the trials, the same isolate and the same experimental design were used as in a previous study where infection was successful by intravenous as well as intracerebral inoculation...
March 2017: Avian Diseases
https://www.readbyqxmd.com/read/28300430/calculated-daily-insulin-dosages-overestimate-prescribed-insulin-doses-in-type-2-diabetes
#5
Karel Kostev, Wolfgang Rathmann
BACKGROUND: The aim was to compare the prescribed and calculated daily insulin dosages based on prescription data in type 2 diabetes patients in a general practice database. METHODS: A total of 17 782 type 2 diabetes patients (age: 70.0 ± 11.5 years; 52% males; 16% diabetologist care) with ≥2 insulin prescriptions from 834 practices were analyzed (Disease Analyser: 01/2011-12/2015). Prescribed daily dosage (PDD) (physician documentation) and calculated daily dose (CDD) (pack size × strength × volume / days between 2 prescriptions) were calculated for short-acting, long-acting, and premixed insulins...
October 1, 2016: Journal of Diabetes Science and Technology
https://www.readbyqxmd.com/read/28297463/technical-note-out-of-field-dose-measurement-at-near-surface-with-plastic-scintillator-detector
#6
Alexandra Bourgouin, Nicolas Varfalvy, Louis Archambault
Out-of-field dose depends on multiple factors, making peripheral dosimetry complex. Only a few dosimeters have the required features for measuring peripheral dose. Plastic scintillator dosimeters (PSDs) offer numerous dosimetric advantages as required for out-of-field dosimetry. The purpose of this study is to determine the potential of using PSD as a surface peripheral dosimeter. Measurements were performed with a parallel-plate ion chamber, a small volume ion chamber, and with a PSD. Lateral-dose measurements (LDM) at 0...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297456/is-the-dose-distribution-distorted-in-imrt-and-rapidarc-treatment-when-patient-plans-are-swapped-across-beam-matched-machines
#7
Chockkalingam Krishnappan, Chandrasekaran Anu Radha, Vendhan Subramani, Madhan Kumar Gunasekaran
The purpose of this study is to evaluate the degree of dose distribution distortion in advanced treatments like IMRT and RapidArc when patient plans are swapped across dosimetrically equivalent so-called "beam-matched" machines. For this purpose the entire work is divided into two stages. At forefront stage all basic beam properties of 6 MV X-rays like PDD, profiles, output factors, TPR20/10 and MLC transmission of two beam-matched machines - Varian Clinac iX and Varian 600 C/D Unique - are compared and evaluated for differences...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297447/verification-measurements-of-an-emc-algorithm-using-a-2d-ion-chamber-array
#8
Mark D Wanklyn, Ghirmay Kidane, Liz Crees
The aim of this study was to assess the suitability of the Im'RT MatriXX 2D ion chamber array for performing verification measurements on the Varian Eclipse electron Monte Carlo (eMC) algorithm for a range of clinical energies (6, 12, and 20 MeV) on a Varian 2100iX linear accelerator. Firstly, the suitability of the MatriXX for measuring percentage depth doses (PDD) in water was assessed, including characterization of the inherent buildup found in the MatriXX. Secondly the suitability of the MatriXX for measuring dose distributions in homogeneous and heterogeneous phantoms was assessed using gamma analysis at 3%/3 mm...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297418/characterization-of-a-2-5-mv-inline-portal-imaging-beam
#9
James L Gräfe, Jennifer Owen, J Eduardo Villarreal-Barajas, Rao F H Khan
A new megavoltage (MV) energy was recently introduced on Varian TrueBeam linear accelerators for imaging applications. This work describes the experimental characterization of a 2.5 MV inline portal imaging beam for commissioning, routine clinical use, and quality assurance purposes. The beam quality of the 2.5 MV beam was determined by measuring a percent depth dose, PDD, in water phantom for 10×10 cm2 field at source-to-surface distance 100 cm with a CC13 ion chamber, plane parallel Markus chamber, and GafChromic EBT3 film...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297340/dosimetric-properties-of-equivalent-quality-flattening-filter-free-fff-and-flattened-photon-beams-of-versa-hd-linear-accelerator
#10
Mukesh N Meshram, Srimanta Pramanik, C P Ranjith, Saravana K Gopal, Rishabh Dobhal
This study presents the basic dosimetric properties of photon beams of a Versa HD linear accelerator (linac), which is capable of delivering flattening filter-free (FFF) beams with a beam quality equivalent to the corresponding flattened beams based on comprehensive beam data measurement. The analyzed data included the PDDs, profiles, penumbra, out-of-field doses, surface doses, output factors, head and phantom scatter factors, and MLC transmissions for both FFF and flattened beams of 6 MV and 10 MV energy from an Elekta Versa HD linac...
May 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297295/a-comparison-of-methods-for-monitoring-photon-beam-energy-constancy
#11
Song Gao, Peter A Balter, Mark Rose, William E Simon
In extension of a previous study, we compared several photon beam energy metrics to determine which was the most sensitive to energy change; in addition to those, we accounted for both the sensitivity of each metric and the uncertainty in determining that metric for both traditional flattening filter (FF) beams (4, 6, 8, and 10 MV) and for flattening filter-free (FFF) beams (6 and 10 MV) on a Varian TrueBeam. We examined changes in these energy metrics when photon energies were changed to ±5% and ±10% from their nominal energies: 1) an attenuation-based metric (the percent depth dose at 10 cm depth, PDD(10)) and, 2) profile-based metrics, including flatness (Flat) and off-axis ratios (OARs) measured on the orthogonal axes or on the diagonals (diagonal normalized flatness, FDN)...
November 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28296317/validation-of-total-skin-electron-irradiation-tsei-technique-dosimetry-data-by-monte-carlo-simulation
#12
Alexander Nevelsky, Egor Borzov, Shahar Daniel, Raquel Bar-Deroma
Total skin electron irradiation (TSEI) is a complex technique which requires many nonstandard measurements and dosimetric procedures. The purpose of this work was to validate measured dosimetry data by Monte Carlo (MC) simulations using EGSnrc-based codes (BEAMnrc and DOSXYZnrc). Our MC simulations consisted of two major steps. In the first step, the incident electron beam parameters (energy spectrum, FWHM, mean angular spread) were adjusted to match the measured data (PDD and profile) at SSD=100 cm for an open field...
July 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28290786/-predictors-of-heart-failure-with-preserved-ejection-fraction-in-patients-with-metabolic-syndrome-and-preclinical-diastolic-dysfunction
#13
K G Adamyan, L G Tunyan, A L Chilingaryan, L R Tumasyan
PURPOSE: to evaluate differences in echocardiographic parameters between patients with preclinical diastolic dysfunction (PDD) and heart failure with preserved ejection fraction (HFpEF) and to identify predictors of transition from PDD to HFpEF. MATERIAL AND METHODS: Echocardiographic parameters were recorded in 325 patients with PDD and 50 healthy subjects. PDD and HFpEF were diagnosed by tissue Doppler imaging of the left ventricle (LV) during exercise stress test and detection of symptoms of heart failure...
February 2017: Kardiologiia
https://www.readbyqxmd.com/read/28284618/a-proteomic-analysis-of-the-iron-response-of-photobacterium-damselae-subsp-damselae-reveals-metabolic-adaptations-to-iron-levels-changes-and-novel-potential-virulence-factors
#14
Beatriz Puentes, Miguel Balado, José Bermúdez-Crespo, Carlos R Osorio, Manuel L Lemos
Photobacterium damselae subsp. damselae (Pdd) is a marine bacterium that can infect numerous species of marine fish as well as other species including humans. Low iron availability is one of the signs that bacterial pathogens can detect in order to begin colonizing their host, and the reduction of iron levels is a nonspecific host defense strategy that prevents bacterial proliferation. In this work a proteomic approach was used to study the gene expression adaptations of a Pdd strain in response to iron availability...
March 2017: Veterinary Microbiology
https://www.readbyqxmd.com/read/28272546/control-quantum-evolution-speed-of-a-single-dephasing-qubit-for-arbitrary-initial-states-via-periodic-dynamical-decoupling-pulses
#15
Ya-Ju Song, Qing-Shou Tan, Le-Man Kuang
We investigate the possibility to control quantum evolution speed of a single dephasing qubit for arbitrary initial states by the use of periodic dynamical decoupling (PDD) pulses. It is indicated that the quantum speed limit time (QSLT) is determined by initial and final quantum coherence of the qubit, as well as the non-Markovianity of the system under consideration during the evolution when the qubit is subjected to a zero-temperature Ohmic-like dephasing reservoir. It is shown that final quantum coherence of the qubit and the non-Markovianity of the system can be modulated by PDD pulses...
March 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28269775/reduction-of-rpt6-s8-a-proteasome-component-and-proteasome-activity-in-the-cortex-is-associated-with-cognitive-impairment-in-lewy-body-dementia
#16
Amani Alghamdi, Julie Vallortigara, David R Howlett, Martin Broadstock, Tibor Hortobágyi, Clive Ballard, Alan J Thomas, John T O'Brien, Dag Aarsland, Johannes Attems, Paul T Francis, David R Whitfield
Lewy body dementia is the second most common neurodegenerative dementia and is pathologically characterized by α-synuclein positive cytoplasmic inclusions, with varying amounts of amyloid-β (Aβ) and hyperphosphorylated tau (tau) aggregates in addition to synaptic loss. A dysfunctional ubiquitin proteasome system (UPS), the major proteolytic pathway responsible for the clearance of short lived proteins, may be a mediating factor of disease progression and of the development of α-synuclein aggregates. In the present study, protein expression of a key component of the UPS, the RPT6 subunit of the 19S regulatory complex was determined...
2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28268531/non-rigid-mri-ct-registration-for-effective-planning-of-prostate-brachytherapy
#17
I Hamdan, G Dardenne, J Bert, D Visvikis
Prostate brachytherapy is an intraoperative radiotherapy technique for irradiating prostate tumors by placing radioactive sources inside the prostate. CT image is used to calculate a personalized dose distribution (PDD) while the MRI is used to visualize the tumor and the organs at risk. Therefore, a registration of preoperative MRI and CT is essential since it could improve the overall precision of the treatment planning, the placement of radioactive sources inside the prostate as well as the visualization of the dose distribution with respect to the tumor...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28257041/photodynamic-detection-of-peritoneal-metastases-using-5-aminolevulinic-acid-ala
#18
REVIEW
Yutaka Yonemura, Yoshio Endo, Emel Canbay, Yang Liu, Haruaki Ishibashi, Akiyoshi Mizumoto, Masamitu Hirano, Yuuki Imazato, Nobuyuki Takao, Masumi Ichinose, Kousuke Noguchi, Yan Li, Satoshi Wakama, Kazuhiro Yamada, Koutarou Hatano, Hiroshi Shintani, Hiroyuki Yoshitake, Shun-Ichiro Ogura
In the past, peritoneal metastasis (PM) was considered as a terminal stage of cancer. From the early 1990s, however, a new comprehensive treatment consisting of cytoreductive surgery and perioperative chemotherapy has been established to improve long-term survival for selected patients with PM. Among prognostic indicators after the treatment, completeness of cytoreduction is the most independent predictors of survival. However, peritoneal recurrence is a main cause of recurrence, even after complete cytoreduction...
March 1, 2017: Cancers
https://www.readbyqxmd.com/read/28255953/correlation-between-prescribed-daily-dose-seizure-freedom-and-defined-daily-dose-in-antiepileptic-drug-treatment
#19
László Horváth, Klára Fekete, Sándor Márton, István Fekete
Background Although defined daily doses (DDD) for antiepileptic drugs (AED) have been assigned only in combination therapy, based on the literature, most patients take them in monotherapy. Furthermore, discrepancies between DDD and prescribed daily dose (PDD) were observed. Objective First, to determine PDDs of AEDs and to reveal PDD/DDD ratio among seizure free versus not seizure free patients in everyday clinical practice. Second, to test the applicability of 75% cut-off of DDD to achieve seizure freedom...
March 2, 2017: International Journal of Clinical Pharmacy
https://www.readbyqxmd.com/read/28247741/-a-systematic-review-and-meta-analysis-to-assess-the-recurrence-free-survival-in-non-muscle-invasive-bladder-cancer-after-transurethral-resection-guided-by-5-aminolevulinic-acid-induced-photodynamic-diagnosis-compared-with-white-light-transurethral-resect
#20
A I Rolevich, A A Evmenenko
INTRODUCTION: We conducted a meta-analysis assessing the effect of photodynamic diagnosis (PDD) -guided transurethral resection of the bladder tumor (TURB) on the recurrence-free survival in patients with non-muscle invasive bladder cancer within prospective randomised trials that used 5-aminolevulinic acid as a photosensitizer. MATHERIAL AND METHODS: Medical literature search was performed up to February 2016. Recurrence hazard ratios (HRs) and its 95% confidence intervals (CI) were calculated for each selected study with direct and indirect methods and the pooled estimates were obtained with random-effects model...
August 2016: Urologii︠a︡
keyword
keyword
63604
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"