نتایج جستجو برای: digital ncat phantom
تعداد نتایج: 324200 فیلتر نتایج به سال:
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...
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 ...
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...
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...
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...
(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...
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...
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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