نتایج جستجو برای: ray computed

تعداد نتایج: 431187  

2004
Richard Gordon

With the advent of industrial computed tomography (CT or reconstruction from projections), which is of much wider scope than medical CT, the basic mathematical and physical assumptions need to be reconsidered. This paper considers the ramifications of the indeterminacy theorem and the underdetermined nature of the reconstruction equations. A search for truth rather than honesty in their solutio...

Journal: :Journal of X-ray science and technology 2014
Andrei Dabravolski Kees Joost Batenburg Jan Sijbers

BACKGROUND In computed tomography (CT), the source-detector system commonly rotates around the object in a circular trajectory. Such a trajectory does not allow to exploit a detector fully when scanning elongated objects. OBJECTIVE Increase the spatial resolution of the reconstructed image by optimal zooming during scanning. METHODS A new approach is proposed, in which the full width of the...

2017
Cristian T. Badea

X-ray computed tomography (CT) systems with high resolution (also known as micro-CT systems) have been developed over the last two decades and have been used with great success in small animal studies. A micro-CT scanner is based on the same underlying physical principle as a clinical CT scanner, but it is designed for higher-resolution imaging. It produces three-dimensional (3D) tomographic da...

2016
Jian Fu Zhenzhong Liu Jingzheng Wang

Most existing X-ray computed tomography (CT) techniques work in single-mounted mode and need to scan the inspected objects one by one. It is time-consuming and not acceptable for the inspection in a large scale. In this paper, we report a multi-mounted CT method and its first engineering implementation. It consists of a multi-mounted scanning geometry and the corresponding algebraic iterative r...

2015
R. W. Obbard

Introduction Conclusions References Tables Figures

Journal: :the journal of tehran university heart center 0
mohammad bagher rahim shariati general hospital, tehran university of medical sciences, tehran, iran. mohammadhossein mandegar shariati general hospital, tehran university of medical sciences, tehran, iran. farideh roshanali shariati general hospital, tehran university of medical sciences, tehran, iran.

a 50-year-old male underwent a check-up for an insurance company. chest x-ray revealed a large ball-like lesion in the posterior mediastinum. the finding was confirmed by computed tomography (ct) scan (figure 1). the patient was referred to our center, where he had a successful mass removal surgery (figure 2). pathology identified the mass as neurinoma.

Ali Reza Shakibafard Fariba Zarei, Mahdi Dodangeh Reza Jalli, Rezvan Ravanfar Haghighi, S. Chatterjee Sepideh Sefidbkht Somayeh Gholami Bardeji Vani VC

Introduction: The basis of image formation in Computed Tomography (CT) lies in the x-ray linear attenuation coefficient of the scanned material. Compton scattering and photoelectric effect are the dominant interactions of the x-ray photons with the subject, in the range of diagnostic radiology. These two coefficients are important in tissue characterization by Dual-Energy CT (D...

Background: In general, radiotherapy treatment planning is performed using the virtual bolus. It is necessary to investigate physical bolus in comparison to virtual one. Objectives: In the present study, first, radiological properties of superflab Gel bolus and Paraffin wax bolus was investigated in terms of their relative electron density. Then, dosimetric performance of both the bolus (...

Journal: :Japanese Journal of Radiological Technology 1990

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