نتایج جستجو برای: based phantom

تعداد نتایج: 2946802  

Journal: :iranian journal of radiation research 0
a. vahidian kamyad department of mathematic, ferdowsi university, mashad, iran m.h. noori eskandari department of mathematic, ferdowsi university, mashad, iran m. naji midani department of medical physics, mashad university for medical sciences, mashad, iran m. hajizadeh saffar department of medical physics, mashad university for medical sciences, mashad, iran

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 wise line...

Objective(s): Use of a positron emission tomography (PET)/single-photonemission computed tomography (SPECT) system facilitates the simultaneousacquisition of images with fluorine-18 fluorodeoxyglucose (18F-FDG) andtechnetium (99mTc)-tetrofosmin. However, 18F has a short half-life, and 511keV Compton-scattered photons are detected in the 99mTc energy window.Therefore, in this study, we aimed to ...

Introduction: The present study aimed to generate intensity-modulated beams with Aluminium compensating filters for a conventional telecobalt machine based on the outputs of a treatment planning system (TPS) performing forward planning and cannot simulate directly the compensating filter. Materials and Methods: In order to achieve the beam intensity modulation during treatment planning with th...

Journal: :The Lancet. Neurology 2002
Herta Flor

Phantom-limb pain is a common sequela of amputation, occurring in up to 80% of people who undergo the procedure. It must be differentiated from non-painful phantom phenomena, residual-limb pain, and non-painful residual-limb phenomena. Central changes seem to be a major determinant of phantom-limb pain; however, peripheral and psychological factors may contribute to it. A comprehensive model of...

Introduction: Use of SPECT/CT data is the most accurate method for patient-specific internal dosimetry when isotopes emit single gamma rays. The manual or semi-automatic segmentation of organs is a major obstacle that slows down and limits the patient-specific dosimetry. Using digital phantoms that mimic patient’s anatomy can bypass the segmentation step and facilitate the dosi...

Journal: :iranian journal of medical physics 0
fatemeh lotfalizadeh department of ray-medical engineering, shiraz university, shiraz, iran mehrnoosh karimipourfard department of ray-medical engineering, shiraz university, shiraz, iran bentolhoda amanat department of physics, payame noor university, tehran, iran mehdi zehtabian department of ray-medical engineering, shiraz university, shiraz, iran

introduction based on task group no. 43 (tg-43u1) recommendations, water phantom is proposed as a reference phantom for the dosimetry of brachytherapy sources. the experimental determination of tg-43 parameters is usually performed in water-equivalent solid phantoms. the purpose of this study was to determine the conversion factors for equalizing solid phantoms to water. materials and methods t...

Journal: :Physical Review Materials 2021

Defect engineering plays an important role in tailoring the electronic transport properties of van der Waals materials. Methods reported so far mainly rely on $e\phantom{\rule{0}{0ex}}x\phantom{\rule{0.333em}{0ex}}s\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}u$ defect type and concentration, hindering realization new types device functionalities associated with engine...

Daryoush Shahbazi Gahrouei Mohammad B. Tavakoli Mojtaba Karbalee

Introduction: An accurate and fast radiation dose calculation is essential for successful radiation radiotherapy. The aim of this study was to implement a new graphic processing unit (GPU) based radiation therapy treatment planning for accurate and fast dose calculation in radiotherapy centers. Materials and Methods: A program was written for parallel runnin...

Introduction: The present study was conducted with the aim of designing a liver phantom for dosimetry. To benchmark the results obtained by the developed liver phantom, another method was applied for the dosimetry of a real liver tissue using imaging. Materials and Methods: For the purpose of the study, a real liver tissue was converted into a phantom based on thegram-molecular weight of the co...

Journal: :Physical review 2022

The silicon-vacancy (SiV) and germanium-vacancy (GeV) centers in diamond have a sharp photoluminescence with high brightness. In this work, the of these is measured up to 180 GPa using nanodiamonds integrated anvil cell. results show blueshifts mean emission energy determined by atomic radii impurity. agreement $a\phantom{\rule{0}{0ex}}b$ $i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phant...

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