A data-driven wall model for turbulent flows over periodic hills is developed using a feedforward neural network and wall-resolved large-eddy simulation data. The employs wall-normal distance, near-wall velocities, pressure gradients as input features, the shear stresses output labels, respectively. In $a$ $p\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}o\phantom{\rule{...

The aim of this study was to investigate the extent to which measurements made in an ADC (apparent diffusion coefficient) calibration phantom could be shown to correlate with accuracies of measurements made in normal liver. Ideally, a strong correlation might be used in the future in order to perform an assessment of scanner performance based entirely on the phantom. Several metrics of image qu...

Background:  This study presents patient specific and organ dose estimation in computed tomography (CT) imaging of thorax directly from patient CT image using Monte Carlo simulation.  Patient's CT image is considered as the patient specific phantom and the best representative of patient physical index in order to calculate specific organ dose. Materials and Methods: EGSnrc /BEAMnr...

Background: Photon attenuation as an inevitable physical phenomenon influences on the diagnostic information of SPECT images and results to errors in accuracy of quantitative measurements. This can be corrected via different physical or mathematical approaches. As the correction equation in mathematical approaches is nonlinear, in this study a new method of linearization called ‘Piece ...

Objective(s): We evaluated edge artifacts in relation to phantom diameter and reconstruction parameters in point spread function (PSF)-based positron emission tomography (PET) image reconstruction.Methods: PET data were acquired from an original cone-shaped phantom filled with 18F solution (21.9 kBq/mL) for 10 min using a Biograph mCT scanner. The images were reconstructed using the baseline or...

objective: different categories are available for estimating of radiation dose. radioisotopes with the same energy and almost the same physical properties have similar effects. monte carlo technique is a computerized method based on mathematical simulation of physical processes. the main purpose of this study is to show that beta particles are not able to penetrate deep into the water. also dif...

introduction evaluation of the delivered dose of externally wedged photon beams by external diode dosimeters during the treatment process requires the estimation of exit surface dose correction factors in various wedge angles and field sizes. materials and methods a system of absorbed dose evaluation, using p-type diode dosimeters placed on the exit surface of a phantom, was characterized for e...

OBJECTIVE To provide a mechanism-based acute pain management strategy for early phantom limb pain following traumatic amputations and to collect first evidence of its acute and potentially preventative effects on the formation and maintenance of phantom limb pain. The combination of continuous brachial plexus analgesia and prolonged block of N-methyl-D-aspartate (NMDA) receptors over 4 weeks ai...