نتایج جستجو برای: solid phantom

تعداد نتایج: 206123  

Journal: :علوم پیراپزشکی و بهداشت نظامی 0
سید سلمان ذکریایی seyed salman zakariaee department of radiology, faculty of paramedicine, aja university of medical sciences, tehran, iranگروه رادیولوژی، دانشکده ی پیراپزشکی، دانشگاه علوم پزشکی ارتش، تهران، ایران. ولی اله صبا valiallah saba department of radiology, faculty of paramedicine, aja university of medical sciences, tehran, iranگروه رادیولوژی، دانشکده ی پیراپزشکی، دانشگاه علوم پزشکی ارتش، تهران، ایران.

introduction: in diagnostic and therapeutic procedures, dosimetric studies are performed on the dosimetric systems in order to comply the radiation safety standards. monte carlo methods are used due to the high complexity and cost of patient-specific phantom construction. the high complexity of the digitized phantoms greatly increases the time and computational task of the monte carlo calculati...

Journal: :The Journal of chemical physics 2010
Petar D Todorov Leonardus W Jenneskens Joop H van Lenthe

The molecular geometry and the normal modes properties of coronene are investigated by means of DFT(B3LYP) and restricted/Hartree-Fock calculations utilizing basis sets of triple zeta+polarization quality. The interpretation of the infrared and Raman spectra of coronene, especially in solid state, is critically revised. The phantom bands in the solid state, previously not understood, are readil...

Journal: :Medical physics 2006
Geneviève Jarry Sean A Graham Douglas J Moseley David J Jaffray Jeffrey H Siewerdsen Frank Verhaegen

Kilovoltage (kV) cone beam computed tomography (CBCT) images suffer from a substantial scatter contribution. In this study, Monte Carlo (MC) simulations are used to evaluate the scattered radiation present in projection images. These predicted scatter distributions are also used as a scatter correction technique. Images were acquired using a kV CBCT bench top system. The EGSnrc MC code was used...

2005
K Krugh J Esthappan

Purpose: A simple method for verifying the dose point kernel of Ir-192 source used in HDR brachytherapy using Kodak EDR2 film in a spiralphantom. Method and Materials: A spiral solid water phantom availablefrom Gammex International for IMRT QA was modified for this study. A CT scan image of the phantom was acquired with a 10 x 12 inch filmloaded in the spiral groove. A 3.5 mm long 8...

Journal: :Medical physics 2005
Asa Palm Thomas LoSasso

The energy dependence of radiographic film can introduce dosimetric errors when evaluating photon beams. The variation of the film response, which is attributed to the changing photon spectrum with depth and field size, has been the subject of numerous publications in recent years. However, these data show large unexplained differences in the magnitude of this variation among independent studie...

Journal: :Physics in medicine and biology 2009
R J Cooper D Bhatt N L Everdell Jeremy C Hebden

We describe a phantom for simultaneous electroencephalography (EEG) and near-infrared imaging which consists of a solid, optically turbid and electrically conducting interface enclosing a tissue-mimicking aqueous scattering solution. The interface provides an electrical contact impedance comparable to that of the human scalp while the phantom as a whole has optical properties and electrical con...

2002
Stephen J. Howlett Tomas Kron

This paper presents an anthropomorphic phantom study of dose delivered to a specific point during tangential breast irradiation to verify monitor unit calculations. Measurements were made using a 0.6 cc Farmer type cylindrical ionization chamber in the phantom and compared to calculations made on a three-dimensional radiotherapy treatment planning system using single digitized contour through t...

2014
Vyacheslav A. Shurshakov Raisa V. Tolochek Ivan S. Kartsev Vladislav M. Petrov Igor V. Nikolaev Svetlana I. Moskalyova Vladimir I. Lyagushin

Space radiation is known to be key hazard of manned space mission. To estimate accurately radiation health risk detailed study of dose distribution inside human body by means of human phantom is conducted. In the space experiment MATROSHKA-R, the tissue-equivalent spherical phantom (32 kg mass, 35 cm diameter and 10 cm central spherical cave) made in Russia has been used on board the ISS for mo...

Journal: :Physics in medicine and biology 2008
Shu-Hui Hsu Peter L Roberson Yu Chen Robin B Marsh Lori J Pierce Jean M Moran

Skin dose assessment for chest wall radiotherapy is important to ensure sufficient dose to the surface target volume without excessive skin reaction. This study quantified changes to the surface doses as a function of bolus material for conventional and intensity modulated radiation therapy (IMRT) tangential fields. Three types of bolus materials (2 mm solid, 2 mm fine mesh and 3.2 mm large mes...

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