نتایج جستجو برای: ncat phantom

تعداد نتایج: 17315  

Ghazale Geraily, Heydar Toolee Shaghayegh Fahimi Monzari

Introduction: Total Skin Electron Therapy (TSET) and Total Body Irradiation (TBI) are kinds of treatment which use electron and photon beams to treat special types of cancers. The aim of these techniques are to deliver uniform dose to the entire skin while minimizing delivered dose to organs at risk. To check the homogeneity of dose delivery in TBI and TSET, using a humanoid ph...

ذکریایی, سید سلمان, صبا, ولی اله,

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...

2017
Syahir Mansor Elisabeth Pfaehler Dennis Heijtel Martin A. Lodge Ronald Boellaard Maqsood Yaqub

PURPOSE In longitudinal oncological and brain PET/CT studies, it is important to understand the repeatability of quantitative PET metrics in order to assess change in tracer uptake. The present studies were performed in order to assess precision as function of PET/CT system, reconstruction protocol, analysis method, scan duration (or image noise), and repositioning in the field of view. METHO...

Journal: :Physics in medicine and biology 2011
Melanie Freed Andreu Badal Robert J Jennings Hugo de las Heras Kyle J Myers Aldo Badano

The purpose of this study is to characterize the x-ray properties of a dual-modality, anthropomorphic breast phantom whose MRI properties have been previously evaluated. The goal of this phantom is to provide a platform for optimization and standardization of two- and three-dimensional x-ray and MRI breast imaging modalities for the purpose of lesion detection and discrimination. The phantom is...

Journal: :iranian journal of medical physics 0
e. raeisi ph.d. student in medical physics, tarbiat modarres university, tehran, iran. h. rajabi assistant professor, medical physics dept., tarbiat modarres university, tehran, iran. s. seifollahy m.d., dept. of nuclear medicine, rajaei heart centere, tehran, iran. e. hajizadeh associate professor, dept. of biostatistics, tarbiat modarres university, tehran, iran.

introduction:  the  purpose  of  this  study  is  to  define  the  optimal  parameters  for  the  tomographic  reconstruction procedure in a routine single photon emission tomography. the hoffman brain phantom  is modified to evaluate the reconstruction method. the phantom was imaged in a 3 and 2-dimensional  conformation and the results were compared.   materials  and  methods:  the  2d  phant...

2017
Sossena Wood Narayanan Krishnamurthy Tales Santini Shailesh Raval Nadim Farhat John Andy Holmes Tamer S. Ibrahim

OBJECTIVE The purpose of this study is to design an anthropomorphic heterogeneous head phantom that can be used for MRI and other electromagnetic applications. MATERIALS AND METHODS An eight compartment, physical anthropomorphic head phantom was developed from a 3T MRI dataset of a healthy male. The designed phantom was successfully built and preliminarily evaluated through an application tha...

Journal: :iranian journal of medical physics 0
alireza vejdani-noghreiyan physics department, faculty of sciences, university of neyshabur, neyshabur, iran, atiyeh ebrahimi-khankook physics department, faculty of sciences, university of neyshabur, neyshabur, iran,

introduction accurate estimation of the absorbed dose in radiosensitive organs, located away from the target volume during radiotherapy, is one of the main reasons for the development of reference phantoms. the international commission on radiological protection (icrp) reference phantoms can provide a more realistic view of the human anatomy in comparison with the previously used mathematical p...

2004
H. Štefančić

We examine cosmological models with generalized phantom energy (GPE). Generalized phantom energy satisfies the supernegative equation of state, but its evolution with the scale factor is generally independent, i.e. not determined by its equation of state. The requirement of general covariance makes the gravitational constant time-dependent. It is found that a large class of distinct GPE models ...

2002
James Cheney Ralf Hinze

Phantom types are data types with type constraints associated with different cases. Examples of phantom types include typed type representations and typed higher-order abstract syntax trees. These types can be used to support typed generic functions, dynamic typing, and staged compilation in higher-order, statically typed languages such as Haskell or Standard ML. In our system, type constraints...

2010
Zhijun Cai Er-Wei Bai Robert McCabe Moustafa Zerhouni Ge Wang Madhavan Lakshmi Raghavan Jarin Kratzberg

Computed Tomography (CT) and Magnetic Resonance (MR) imaging techniques have become an important role in diagnosing the vascular diseases. Before a clinical trial of the newly developed techniques, it is essential to evaluate them on a phantom. However, there is no existing arterial A Dynamic Arterial Tree Phantom for studies 89 tree phantom that serves for flood flows. To that end, we design a...

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