Determination Of Inherent Contrast Resolution In X-Ray Imaging Using Electron Density And Effective Atomic Number Differences

1984 ◽  
Author(s):  
Frank A. DiBianca ◽  
Joan E. Fetter ◽  
Marion D. Barker
2020 ◽  
Vol 38 ◽  
pp. 93-99
Author(s):  
Hiroshi Sakurai ◽  
Kazushi Hoshi ◽  
Yosuke Harasawa ◽  
Daiki Ono ◽  
Kun Zhang ◽  
...  

We developed the photon counting CT system by using a conventional laboratory X-ray source and a CdTe line sensor. Attenuation coefficients were obtained from the measured CT image data. Our suggested method for deriving the electron density and effective atomic number from the measured attenuation coefficients was tested experimentally. The accuracy of the electron densities and effective atomic numbers are about <5 % (the averages of absolute values are 2.6 % and 3.1 %, respectively) for material of 6< Z and Zeff <13. Our suggested simple method, in which we do not need the exact source X-ray spectrum and detector response function, achieves comparable accuracy to the previous reports.


Computed tomography is a method for obtaining a series of radiographic pictures of contiguous slices through a solid object such as the human body. Each picture is computed from a set of X-ray transmission measurements and represents the distribution of X-ray attenuation in the slice. The high sensitivity of the method to changes in both density and atomic number has resulted in the development of new diagnostic methods in medicine. The limitations of the method are discussed in terms of two particular kinds of application. First, those applications in which a very precise determination of density or atomic number is required, but at low spatial resolution; an example would be the determination of the uniformity of mixture of plastics or metals. The second kind of application is that requiring high spatial resolution as in the detection of cracks and the visualization of internal structures in complicated objects.


2015 ◽  
Vol 1085 ◽  
pp. 455-459 ◽  
Author(s):  
Sergei P. Osipov ◽  
Vasilii A. Klimenov ◽  
Oleg S. Osipov ◽  
Vil'dan D. Samigullin ◽  
Aleksandr M. Shtein

The paper presents foundations of the algorithm of processing primary radiographic images of large-size cargoes that allows determination of their masses. Two possible approaches to form definite algorithm of processing radiographic information were analyzed. The choice of the approaches depends on the completeness of information about the test object. The first approach to design mass determination algorithm is connected with inspecting industrial products. Industrial inspecting products are characterized by a completeness of information about the material, its structure, the geometry. The information augmented by selecting maximum X-ray energy and calibrating by test object allows determination the mass of inspecting object by the only radiographic image with high precision. The second approach is caused by indeterminacy and incomplete information about inspecting object. This case is typical for problems of cargo inspection. Corresponding algorithm modification is based on using dual-energy X-ray imaging that allows determination of the effective atomic number of test object and provision of the required precision of mass estimation.


2018 ◽  
Vol 25 (6) ◽  
pp. 1797-1802 ◽  
Author(s):  
Zhijun Chi ◽  
Yingchao Du ◽  
Lixin Yan ◽  
Dong Wang ◽  
Hongze Zhang ◽  
...  

Unlike large-scale and expensive synchrotron radiation facilities, the Thomson scattering X-ray source can provide quasi-monochromatic, energy-tunable and high-brightness X-ray pulses with a small footprint and moderate cost, making it an excellent candidate for dual-energy and multi-energy imaging at laboratories and hospitals. Here, the first feasibility study on dual-energy computed tomography (CT) based on this type of light source is reported, and the effective atomic number and electron-density distribution of a standard phantom consisting of polytetrafluoroethylene, water and aluminium is derived. The experiment was carried out at the Tsinghua Thomson scattering X-ray source with peak energies of 29 keV and 68 keV. Both the reconstructed effective atomic numbers and the retrieved electron densities of the three materials were compared with their theoretical values. It was found that these values were in agreement by 0.68% and 2.60% on average for effective atomic number and electron density, respectively. These results have verified the feasibility of dual-energy CT based on the Thomson scattering X-ray source and will further expand the scope of X-ray imaging using this type of light source.


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