نتایج جستجو برای: x ray ct

تعداد نتایج: 753974  

2015
FERGUS J. RUGG-GUNN

The superiority of magnetic resonance imaging (MRI) over X-ray computed tomography (CT) scanning in terms of sensitivity and specificity for identifying the aetiology of epilepsy in both adults and children is firmly established. The most common abnormalities identified are hippocampal sclerosis (HS), malformations of cortical development (MCD), vascular malformations, tumours, and acquired cor...

2013
Mou An Yaoqin Xie

Current computed tomography (CT) scanners rotate fast to reduce motion artifact. X-ray tube must work in a high power to make the image clear under short exposure time. However, the life span of such a tube may be shortened. In this paper, we propose a novel double sources CT imaging system, which puts two of the same X-ray sources closely with each other. The system is different from current d...

2013
Giancarlo Cordasco Marco Portelli Angela Militi Riccardo Nucera Antonino Lo Giudice Elda Gatto Alessandra Lucchese

BACKGROUND The aim of this study was to evaluate the amount of radiation doses absorbed by soft tissues (entrance skin dose) with a low-dose spiral computed tomography (CT) protocol compared to conventional X-ray techniques commonly used in orthodontics. METHODS The amount of skin dose has been evaluated using a tissue-equivalent head-neck radiotherapy humanoid phantom with thermoluminescent ...

2016
Maryam Mobini Leyla Dehghan Gholamali Yosefi Alireza Mohammadpour Rohollah Abdi

BACKGROUND Bisphosphonates (BPs) are used extensively for managing the osteoporosis. There are some controversies on atypical fractures of femur that associated with increase in cortical thickness (CT) and BPs' use. In this study, the effects of alendronate consumption were studied on femoral CT as a predictor for atypical fracture. METHODS Forty nine post-menopausal women aged 50-70 years wi...

2013
Sherman Jordan Kisner Ken Sauer Jan Allebach Thomas Talavage Peter Doerschuk Eri Haneda

Kisner, Sherman J. Ph.D., Purdue University, December 2013. Image Reconstruction for X-ray Computed Tomography in Security Screening Applications. Major Professor: Charles A. Bouman. X-ray tomographic systems have increasingly widespread use in security screening applications. For example, most major airports now utilize X-ray CT systems for efficient screening of baggage and cargo. While decad...

2013
Yong Shi George Helou Lee Armus

We estimate the abundance of Compton-thick (CT) active galactic nuclei (AGN) based on our joint model of X-ray and infrared backgrounds. At Lrest2−10keV > 10 42 erg/s, the CT AGN density predicted by our model is a few ×10 Mpc from z=0 up to z=3. CT AGN with higher luminosity cuts (> 10, 10 & 10 erg/s) peak at higher z and show a rapid increase in the number density from z=0 to z∼2-3. The CT to...

Journal: :Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics 2012
Marcel Beister Daniel Kolditz Willi A Kalender

Iterative reconstruction (IR) methods have recently re-emerged in transmission x-ray computed tomography (CT). They were successfully used in the early years of CT, but given up when the amount of measured data increased because of the higher computational demands of IR compared to analytical methods. The availability of large computational capacities in normal workstations and the ongoing effo...

2006
Alexander SASOV

Using advanced X-ray technologies and X-ray scattering enhancement in signal detection, a compact laboratory X-ray scanner for 3D non-invasive imaging with 150-200 nanometers 3D detail detectability has been created. This spatial resolution in the volume terms is equal or better than can be achieved in synchrotron tomography, 5 orders better than in existing laboratory instruments and 10-12 ord...

2011
Robert Azencott Anando Sen Bernhard G. Bodmann King C. Li Demetrio Labate Xiaobo Zhou

The method presented in this paper aims to reduce the overall radiation exposure from X-ray CT scans when only the reconstruction of a region of interest is required. To achieve this goal, the Searchlight CT algorithm restricts the acquisition to X-rays passing mainly through the region of interest. The algorithm uses an iteration of the X-ray transform and of a regularized inverse, which conve...

2006
Alexei Ramotar Jeff Orchard

We present an efficient and accurate reconstruction technique for computed tomography (CT) images from a geometrically unconstrained set of ray sums. Current CT-scanners are immobile. However, a new era in x-ray production could usher in new, lightweight, flexible and portable x-ray devices. The proposed device, currently under development, is envisioned as a flexible band with tiny x-ray emitt...

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