نتایج جستجو برای: phantoms

تعداد نتایج: 12252  

Journal: :Ultrasonic imaging 2013
Alexander D Pawlicki William D O'Brien

Estimating total ultrasound attenuation from backscatter data is essential in the field of quantitative ultrasound (QUS) because of the need to compensate for attenuation when estimating the backscatter coefficient and QUS parameters. This work uses a reference phantom method of attenuation estimation to create a spatial map of attenuation slope (AS) from backscatter radio-frequency (RF) data o...

2011
Manzoor Ahmad Sanaz Alali Anthony Kim Michael F. G. Wood Masroor Ikram I. Alex Vitkin

We here investigate polarimetric behavior of thick samples of porcine liver, Intralipid, and microsphere-based tissue phantoms whose absorption and scattering properties are matched. Using polarized light we measured reflection mode Mueller matrices and derived linear/circular/total depolarization rates, based on polar decomposition. According to our results, phantoms exhibit greater depolariza...

2014
Liang Mei Gabriel Somesfalean Sune Svanberg

In the present work, fiber-based frequency-modulated light scattering interferometry (FMLSI) is developed and employed for studies of optical properties and dynamics in liquid phantoms made from Intralipid(®). The fiber-based FMLSI system retrieves the optical properties by examining the intensity fluctuations through the turbid medium in a heterodyne detection scheme using a continuous-wave fr...

2010
aniel M. de Bruin G. van Leeuwen

irk J. Faber niversity of Amsterdam cademic Medical Center epartment of Biomedical Engineering and Physics and pththalmology Department msterdam, 1100 DE Netherlands Abstract. Current innovations in optical imaging, measurement techniques, and data analysis algorithms express the need for reliable testing and comparison methods. We present the design and characterization of silicone elastomer-b...

Journal: :Journal of biomedical optics 2010
Daniel M de Bruin Rolf H Bremmer Vitali M Kodach Roy de Kinkelder Jan van Marle Ton G van Leeuwen Dirk J Faber

Current innovations in optical imaging, measurement techniques, and data analysis algorithms express the need for reliable testing and comparison methods. We present the design and characterization of silicone elastomer-based optical phantoms. Absorption is included by adding a green dye and scattering by adding TiO(2) or SiO(2) particles. Optical coherence tomography measurements demonstrate a...

M. Allahverdi, M.H. Zahmatkesh, M.R. Ay, N. Riyahi Alam, T. Allahverdi Pourfallah,

Background: Polymer gel dosimetry is still the only dosimetry method for direct measuring of threedimensional dose distributions. MRI Polymer gel dosimeters are tissue equivalent and can act as a phantom material. In this study the obtained isodose maps with PAGAT polymer gel dosimeter were compared to those calculated with EGSnrs for singleshot irradiations of 8 and 18 mm collimators of...

Journal: :Journal of biomedical physics & engineering 2023

Background: Methods for segmentation, i.e., Full-segmentation (FS) and Segmentation-rotation (SR), are proposed maintaining Computed Tomography (CT) number linearity. However, their effectiveness has not yet been tested against noise.Objective: This study aimed to evaluate the influence of noise on accuracy CT linearity FS SR methods American College Radiology (ACR) computational phantoms.Mater...

Journal: :Physics in medicine and biology 2014
X George Xu

Radiation dose calculation using models of the human anatomy has been a subject of great interest to radiation protection, medical imaging, and radiotherapy. However, early pioneers of this field did not foresee the exponential growth of research activity as observed today. This review article walks the reader through the history of the research and development in this field of study which star...

Journal: :Current Directions in Biomedical Engineering 2021

Abstract Phantoms are essential tools for the development and characterization of Magnetic Particle Imaging (MPI), an imaging technique that can quantitatively map spatial distribution magnetic nanoparticles (MNP). The objective this study was to develop validate a modular MPI phantom kit with high versatility platform-independent quality assurance assembling defined geometries in MPI. It shown...

Journal: :International Economic Review 2022

When vacancies are filled, the job ads often remain, creating phantom vacancies. Older listings more likely represent phantoms. We assume seekers direct their search based on listing age. Forming a match with an age-a vacancy creates probability β and generates externality affecting aged older. Thus, decreases match's Relative to efficient behavior, overapply younger listings. calibrate using U...

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