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Validation cost effectiveness simulation

Hongkai Yang, Kejun Kang, Yuxiang Xing
PURPOSE: The positioning accuracy of each component is important to ensure the image quality of cone-beam CT. However, accurate positioning is not easy and requires experience and time. The option is to calibrate the geometric parameters and then plug them into a reconstruction algorithm which is the preferred solution in practice. In this case, the image quality is determined by the accuracy and precision of the calibration method. This work describes a method to independently calibrate an imaging system in each pose (projection angle) for a cone-beam CT with a non-ideal-circular trajectory...
February 16, 2017: Medical Physics
Irmgard C Schiller-Frühwirth, Beate Jahn, Marjan Arvandi, Uwe Siebert
BACKGROUND: Many Western countries have long-established population-based mammography screening programs. Prior to implementing these programs, decision-analytic modeling was widely used to inform decisions. OBJECTIVE: The aim of this study was to perform a systematic review of cost-effectiveness models in breast cancer screening in the general population to analyze their structural and methodological approaches. METHODS: A systematic literature search for health economic models was performed in the electronic databases MEDLINE (Ovid), EMBASE, CRD Databases, Cochrane Library, and EconLit in August 2011 with updates in June 2013, April 2015, and November 2016...
February 10, 2017: Applied Health Economics and Health Policy
Matthew Hamilton, Guy Mahiane, Elric Werst, Rachel Sanders, Olivier Briët, Thomas Smith, Richard Cibulskis, Ewan Cameron, Samir Bhatt, Daniel J Weiss, Peter W Gething, Carel Pretorius, Eline L Korenromp
BACKGROUND: Scale-up of malaria prevention and treatment needs to continue but national strategies and budget allocations are not always evidence-based. This article presents a new modelling tool projecting malaria infection, cases and deaths to support impact evaluation, target setting and strategic planning. METHODS: Nested in the Spectrum suite of programme planning tools, the model includes historic estimates of case incidence and deaths in groups aged up to 4, 5-14, and 15+ years, and prevalence of Plasmodium falciparum infection (PfPR) among children 2-9 years, for 43 sub-Saharan African countries and their 602 provinces, from the WHO and malaria atlas project...
February 10, 2017: Malaria Journal
Zaki Sleiman, Elie Atallah, Elie Rassi, Riad Sarkis, Aline Khazzaka
The aim of this study was to describe and validate a homemade laparoscopic trainer. The abdominal cavity is simulated within a 3-mm-thick stainless steel model. Thirty-four participants were evaluated in a pilot study to validate our model. Participants were divided into experts (n = 19) and novices (n = 15) to perform basic and complex laparoscopic skills. The comparison between the homemade trainer (HT) and the standard laparoscopic trainer showed no significant differences for the 2 tasks performed for each group ( P > ...
January 1, 2017: Surgical Innovation
Miao Zhang, Lixin Ma, Ping Yu
We developed a spatial convolution approach for mirror image suppression in phase-modulated Fourier domain optical coherence tomography, and demonstrated it in vivo for small animal imaging. Utilizing the correlation among neighboring A-scans, the mirror image suppression process was simplified to a three-parameter convolution. By adjusting the three parameters, we can implement different Fourier domain sideband windows, which is important but complicated in existing approaches. By properly selecting the window size, we validated the spatial convolution approach on both simulated and experimental data, and showed that it is versatile, fast, and effective...
February 1, 2017: Optics Letters
Jane Candlish, Alexander Pate, Matthew Sperrin, Tjeerd van Staa
BACKGROUND: The cohort multiple randomised controlled trial (cmRCT) design provides an opportunity to incorporate the benefits of randomisation within clinical practice; thus reducing costs, integrating electronic healthcare records, and improving external validity. This study aims to address a key concern of the cmRCT design: refusal to treatment is only present in the intervention arm, and this may lead to bias and reduce statistical power. METHODS: We used simulation studies to assess the effect of this refusal, both random and related to event risk, on bias of the effect estimator and statistical power...
January 31, 2017: BMC Medical Research Methodology
G J A Sevink, F Schmid, T Kawakatsu, G Milano
We have extended an existing hybrid MD-SCF simulation technique that employs a coarsening step to enhance the computational efficiency of evaluating non-bonded particle interactions. This technique is conceptually equivalent to the single chain in mean-field (SCMF) method in polymer physics, in the sense that non-bonded interactions are derived from the non-ideal chemical potential in self-consistent field (SCF) theory, after a particle-to-field projection. In contrast to SCMF, however, MD-SCF evolves particle coordinates by the usual Newton's equation of motion...
January 27, 2017: Soft Matter
Afsaneh Barzi, Heinz-Josef Lenz, David I Quinn, Sarmad Sadeghi
BACKGROUND: Screening for colorectal cancer (CRC) has been successful in decreasing the incidence and mortality from CRC. Although new screening tests have become available, their relative impact on CRC outcomes remains unexplored. This study compares the outcomes of various screening strategies on CRC outcomes. METHODS: A Markov model representing the natural history of CRC was built and validated against empiric data from screening trials as well as the Microstimulation Screening Analysis (MISCAN) model...
January 24, 2017: Cancer
Reda Lebcir, Eren Demir, Raheelah Ahmad, Christos Vasilakis, David Southern
BACKGROUND: The number of people affected by Parkinson's disease (PD) is increasing in the United Kingdom driven by population ageing. The treatment of the disease is complex, resource intensive and currently there is no known cure to PD. The National Health Service (NHS), the public organisation delivering healthcare in the UK, is under financial pressures. There is a need to find innovative ways to improve the operational and financial performance of treating PD patients. The use of community services is a new and promising way of providing treatment and care to PD patients at reduced cost than hospital care...
January 18, 2017: BMC Health Services Research
Antonio Raffo, Sandra Costanzo, Giuseppe Di Massa
A vibration sensor based on the use of a Software-Defined Radio (SDR) platform is adopted in this work to provide a contactless and multipurpose solution for low-cost real-time vibrations monitoring. In order to test the vibration detection ability of the proposed non-contact method, a 1 GHz Doppler radar sensor is simulated and successfully assessed on targets at various distances, with various oscillation frequencies and amplitudes. Furthermore, an SDR Doppler platform is practically realized, and preliminary experimental validations on a device able to produce a harmonic motion are illustrated to prove the effectiveness of the proposed approach...
January 8, 2017: Sensors
Bahe Hachem, Carl-Eric Aubin, Stefan Parent
PURPOSE: Developing fusionless devices to treat pediatric scoliosis necessitates lengthy and expensive animal trials. The objective was to develop and validate a porcine spine numerical model as an alternative platform to assess fusionless devices. METHODS: A parametric finite element model (FEM) of an osseoligamentous porcine spine and rib cage, including the epiphyseal growth plates, was developed. A follower-type load replicated physiological and gravitational loads...
January 9, 2017: European Spine Journal
J Neylon, Y Min, K Hasse, D Low, A Santhanam
PURPOSE: Clinical deformable image registration (DIR) accuracy is difficult to quantify, making validation and verification manual and time consuming. It has also been seen that DIR accuracy can be improved by patient and site specific optimization. We previously investigated a cost function to parameterize image similarity metrics (ISMs) and provide a quantifiable comparison of DIR performance. In this abstract, we characterize and optimize the cost function response (CFR) and correlation to target registration error (TRE) in a dense registration parameter space...
June 2016: Medical Physics
S Jang, T Frometa, A Pyakuryal, T Sio, R Piseaux, S Acosta, K Ocana
PURPOSE: The statistical models (SM) are typically used as a subjective description of a population for which there is only limited sample data, and especially in cases where the relationship between variables is known. The normal tissue complications and tumor control are frequently stochastic effects in the Radiotherapy (RT). Based on probabilistic treatments, it recently has been formulated new NTCP and TCP models for the RT. Investigating the particular requirements for their clinical use in the proton therapy (PT) is the goal of this work...
June 2016: Medical Physics
John Hornberger, Jay Bae, Ian Watson, Joe Johnston, Michael Happich
OBJECTIVE: Amyloid beta (Aβ) positron emission tomography (PET) imaging helps estimate Aβ neuritic plaque density in patients with cognitive impairment who are under evaluation for Alzheimer's disease (AD). This study aims to evaluate the cost-effectiveness of the Aβ-PET scan as an adjunct to standard diagnostic assessment for diagnosis of AD in France, using florbetapir as an example. METHODS: A state-transition probability analysis was developed adopting the French Health Technology Assessment (HTA) perspective per guidance...
January 24, 2017: Current Medical Research and Opinion
Rohan C Parikh, Xianglin L Du, Morgan O Robert, David R Lairson
BACKGROUND: Treatment patterns for metastatic colorectal cancer (mCRC) patients have changed considerably over the last decade with the introduction of new chemotherapies and targeted biologics. These treatments are often administered in various sequences with limited evidence regarding their cost-effectiveness. OBJECTIVE: To conduct a pharmacoeconomic evaluation of commonly administered treatment sequences among elderly mCRC patients. METHODS: A probabilistic discrete event simulation model assuming Weibull distribution was developed to evaluate the cost-effectiveness of the following common treatment sequences: (a) first-line oxaliplatin/irinotecan followed by second-line oxaliplatin/irinotecan + bevacizumab (OI-OIB); (b) first-line oxaliplatin/irinotecan + bevacizumab followed by second-line oxaliplatin/irinotecan + bevacizumab (OIB-OIB); (c) OI-OIB followed by a third-line targeted biologic (OI-OIB-TB); and (d) OIB-OIB followed by a third-line targeted biologic (OIB-OIB-TB)...
January 2017: Journal of Managed Care & Specialty Pharmacy
Ken R Duffy, Neil Gurram, Kelsey C Peters, Genevieve Wellner, Catherine M Grgicak
Short tandem repeat (STR) profiling from DNA samples has long been the bedrock of human identification. The laboratory process is composed of multiple procedures that include quantification, sample dilution, PCR, electrophoresis and fragment analysis. The end-product is an STR electropherogram comprised of signal from allele, artifacts and instrument noise. In order to optimize or alter laboratory protocols, a large number of validation samples must be created at significant expense. As a tool to support that process and to enable the exploration of complex scenarios without costly sample creation, a mechanistic stochastic model that incorporates each of the aforementioned processing features is described herein...
December 16, 2016: Electrophoresis
Simon Olsson, Frank Noé
Long-lived conformational states and their interconversion rates critically determine protein function and regulation. When these states have distinct chemical shifts, the measurement of relaxation by NMR may provide us with useful information about their structure, kinetics, and thermodynamics at atomic resolution. However, as these experimental data are sensitive to many structural and dynamic effects, their interpretation with phenomenological models is challenging, even if only a few metastable states are involved...
December 27, 2016: Journal of the American Chemical Society
Pascal Forquin, Jean-Luc Zinszner
Owing to their significant hardness and compressive strengths, ceramic materials are widely employed for use with protective systems subjected to high-velocity impact loadings. Therefore, their mechanical behaviour along with damage mechanisms need to be significantly investigated as a function of loading rates. However, the classical plate-impact testing procedures produce shock loadings in the brittle sample material which cause unrealistic levels of loading rates. Additionally, high-pulsed power techniques and/or functionally graded materials used as flyer plates to smooth the loading pulse remain costly, and are generally difficult to implement...
January 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Mateusz Marianski, Adriana Supady, Teresa Ingram, Markus Schneider, Carsten Baldauf
A big hurdle when entering the field of carbohydrate research stems from the complications in the analytical and computational treatment. In effect, this extremely important class of biomolecules remains underinvestigated when compared, for example, with the maturity of genomics and proteomics research. On the theory side, the commonly used empirical methods suffer from an insufficient amount of high-quality experimental data against which they can be thoroughly validated. In order to provide a pivotal point for an ascent of accurate carbohydrate simulations, we present here a structure/energy benchmark set of diverse glucose (in three isomeric forms) and α-maltose conformations at the coupled-cluster level as well as an assessment of commonly used energy functions...
December 13, 2016: Journal of Chemical Theory and Computation
Joon Bok Lee, Eyal Dassau, Ravi Gondhalekar, Dale E Seborg, Jordan E Pinsker, Francis J Doyle
Development of an effective artificial pancreas (AP) controller to deliver insulin autonomously to people with type 1 diabetes mellitus is a difficult task. In this paper, three enhancements to a clinically validated AP model predictive controller (MPC) are proposed that address major challenges facing automated blood glucose control, and are then evaluated by both in silico tests and clinical trials. First, the core model of insulin-blood glucose dynamics utilized in the MPC is expanded with a medically inspired personalization scheme to improve controller responses in the face of inter- and intra-individual variations in insulin sensitivity...
November 23, 2016: Industrial & Engineering Chemistry Research
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