نتایج جستجو برای: phantoms gels

تعداد نتایج: 34820  

Introduction: Quality assurance in Computed tomography (CT) centers in developing countries are largely hindered by the unavailability of CT phantoms. The development of a local CT phantom for the measurement of organ radiation absorbed dose is therefore requisite. Material and Methods: Local CT phantoms were designed to meet the standard criteria of 32 cm diameter for body, 16 cm diameter for...

2007
Jouni Uusi–Simola Sami Heikkinen Petri Kotiluoto Tom Serén Tiina Seppälä Iiro Auterinen Sauli Savolainen

Radiation sensitive polymer gels are among the most promising three-dimensional dose verification tools developed to date. Polymer gel dosimeter known by the acronym MAGIC has been tested for evaluation of its use in boron neutron capture (BNCT) dosimetry. We irradiated a large (diameter 10 cm, length 20 cm) cylindrical gel phantom in the epithermal neutron beam of the Finnish BNCT facility at ...

2008
Kevin Koh Tobias Wood Hao Zhang Karim Lekadir Daniel Elson Guang-Zhong Yang

This paper presents an optical system for performing excitation resolved imaging of fluorescent dyes, tissue phantoms and ex vivo tissues. The excitation source was a supercontinuum generated in a highly nonlinear fibre, spectrally filtered using dispersive optics and a movable slit or digital micromirror device. This allowed excitation with multiple spectra, which may be chosen to optimize the...

Journal: :School Science and Mathematics 1902

Journal: :Physics in medicine and biology 2010
Choonsik Lee Daniel Lodwick Jorge Hurtado Deanna Pafundi Jonathan L Williams Wesley E Bolch

Computational human phantoms are computer models used to obtain dose distributions within the human body exposed to internal or external radiation sources. In addition, they are increasingly used to develop detector efficiencies for in vivo whole-body counters. Two classes of computational human phantoms have been widely utilized for dosimetry calculation: stylized and voxel phantoms that descr...

E. Hoseinian Azghadi, H. Miri Hakimabad L. Rafat Motavalli

Annually, many people are irradiated for diagnostic and therapeutic purposes. Assessment of radiation dose and its related risks to patients are important issues in radiation protection dosimetry. The complex mathematical calculations of the absorbed and effective doses are now done with computers. The calculations are performed with the help of anthropomorphic computational models of human bod...

Journal: :Physiological measurement 2006
Punit Prakash Mark C Converse David M Mahvi John G Webster

Phantoms are often used to simulate tissue during the development, testing and calibration of medical devices. In order to infer the specific absorption rate (SAR) and resistive heating in phantoms from temperature measurements, the specific heat capacity and density of the phantom are needed. Stauffer et al (2003 Int. J. Hyperth. 19 89-101) developed several phantoms that mimic dielectric prop...

Journal: :journal of dentistry, tehran university of medical sciences 0
hoorieh bashizadeh fakhar elham sadat emadian razavi sepideh soheilifar mohammad javad kharazifard

objectives: the purpose of this study was to develop and test a new tool for radiographic densitometry by combining periapical films and aluminum step wedge. materials and methods: we reviewed 50 kodak e-speed intraoral films. an aluminum step wedge consisting of 16 steps was constructed. each step was 1mmx3mx10mm. the step wedge was exposed to varying exposure times, ranging from 0.05 second t...

Journal: :Physics in medicine and biology 2000
D D Steele T L Chenevert A R Skovoroda S Y Emelianov

This article presents a method for measuring three-dimensional mechanical displacement and strain fields using stimulated echo MRI. Additional gradient pulses encode internal displacements in response to an externally applied deformation. By limiting the mechanical transition to the stimulated echo mixing time, a more accurate static displacement measurement is obtained. A three-dimensional ela...

Journal: :Radiation research 2017
David Welch Leah Turner Michael Speiser Gerhard Randers-Pehrson David J Brenner

Anatomically accurate phantoms are useful tools for radiation dosimetry studies. In this work, we demonstrate the construction of a new generation of life-like mouse phantoms in which the methods have been generalized to be applicable to the fabrication of any small animal. The mouse phantoms, with built-in density inhomogeneity, exhibit different scattering behavior dependent on where the radi...

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