نتایج جستجو برای: digital ncat phantom

تعداد نتایج: 324200  

Journal: :Radiology 2002
Sankararaman Suryanarayanan Andrew Karellas Srinivasan Vedantham Hetal Ved Stephen P Baker Carl J D'Orsi

PURPOSE To compare the contrast-detail (CD) characteristics of screen-film (SF) and postprocessed digital images by using a phantom-based method. MATERIALS AND METHODS Images of a CD phantom with polymerized methyl methacrylate were acquired with SF and full-field digital mammography systems at matched exposure conditions. A four-alternative forced-choice experiment was conducted with seven o...

Journal: :Nihon Hoshasen Gijutsu Gakkai zasshi 2011
Kunio Kurowarabi Hiroko Abe Hiroshi Horita Kazuyuki Kaneta

A questionnaire survey about mammography in Hokkaido was mailed to 121 facilities from August to September 2009. We surveyed the conditions of digital mammography with regard to quality control (QC) and average glandular dose at 79 facilities in Hokkaido in 2009, and the results of the survey were compared with those of 2004. We found that digital mammography techniques were widely used across ...

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...

2005
N. Karssemeijer M. A. O. Thijssen

Many phantoms have been designed to study mammographic image quality. Not all of these are suitable for use with digital systems. Especially, measurement of spatial resolution with line patterns does not seem appropriate, because microcalcifications, the smallest objects visible in mammograms, are better represented by dot patterns. A phantom in which dot patterns are applied is the CDMAM phant...

Journal: :Hellenic journal of nuclear medicine 2009
Bahareh Shalchian Hossein Rajabi Hamid Soltanian-zadeh

While information about anatomy is available in CT images, information about physiology and metabolism is available in PET images. To integrate both information, the two images are fused. Image fusion methods include simple methods like pixel averaging and sophisticated methods like wavelet transformation. An advantage of using wavelet transformation is that it preserves significant parts of ea...

Journal: :Physics in medicine and biology 2009
N Grotus A J Reader S Stute J C Rosenwald P Giraud I Buvat

(18)F-fluoro-deoxy-glucose ((18)F-FDG) positron emission tomography (PET) is one of the most sensitive and specific imaging modalities for the diagnosis of non-small cell lung cancer. A drawback of PET is that it requires several minutes of acquisition per bed position, which results in images being affected by respiratory blur. Respiratory gating techniques have been developed to deal with res...

Journal: :Medical physics 2000
D E Peplow K Verghese

Monte Carlo simulations of digital images of the contrast detail phantom and the ACR phantom are presented for two different x-ray digital mammography modalities: a synchrotron mammography system and a next-generation scanning slot clinical system. A combination of variance reduction methods made it possible to simulate accurate images using real pixel dimensions within reasonable computation t...

2017
Daniëlle Koopman Maureen Groot Koerkamp Pieter L Jager Hester Arkies Siert Knollema Cornelis H Slump Pedro G Sanches Jorn A van Dalen

BACKGROUND Our aim was to evaluate if a recently introduced TOF PET system with digital photon counting technology (Philips Healthcare), potentially providing an improved image quality over analogue systems, can fulfil EANM research Ltd (EARL) accreditation specifications for tumour imaging with FDG-PET/CT. FINDINGS We have performed a phantom study on a digital TOF PET system using a NEMA NU...

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