scholarly journals Comparison of dual-energy, Z-SCAN, and Z-SPEC material separation techniques for high-energy x-ray cargo inspection

2019 ◽  
Author(s):  
Willem G. J. Langeveld
2012 ◽  
Vol 61 (5) ◽  
pp. 821-824 ◽  
Author(s):  
Jiseoc Lee ◽  
Yunjeong Lee ◽  
Seungryong Cho ◽  
Byung-Cheol Lee

Author(s):  
Zuraida Ramli ◽  
Rafidah Zainon ◽  
Abd Aziz Tajuddin ◽  
Nur Shakila Othman

Dual-energy CT allows the determination of tissue composition based on the different atomic numbers and attenuation profiles of the constituents. The aims of this study is to assess the feasibility of dual-energy CT at Imaging Unit, Advanced Medical, and Dental Institute, USM, to quantify different materials, permitting imaging assessment of elemental deficiencies, metabolic imbalances, and any abnormal tissue in clinical practice. The study was conducted at the Imaging Unit, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Pulau Pinang, Malaysia. The study was performed using a new fabricated abdominal phantom for spectral CT imaging that scanned on the single-source, fast switching dual-energy CT scanner (Somatom Definition; Siemens AG, Wittelsbacherplatz Muenchen, Germany) system in dual-energy mode at tube voltages of 80 kVp for low energy and 140 kVp for high energy using abdominal protocol. The phantom was scanned at 4.0 mm slice thickness and pitch value 1.2 using CAREDose 4D (automated tube current modulation). Four tubes filled with calcium chloride, ferric nitrate, water, and sunflower oil that represents bone, blood, soft tissue, and fat respectively were analyzed in an abdominal phantom. Image post-processing was analyzed. All the tissue-mimicking materials, calcium chloride, ferric nitrate, water, and oil can be differentiated clearly in an unenhanced image scan. By applying the two different energy levels, all these materials can be accurately differentiated from one another based on their differential absorption levels of the x-ray energy. The material separation in the dual-energy CT technique is based on the attenuation interaction in the irradiated materials by applying varies x-ray beam at low and high energy. Furthermore, in clinical practice, a radiation source is usually composed of individual photons with a wide range of energies, and each photon energy is attenuated differently by the types of tissues in the human body. Material separation can be accurately quantified with a dual-energy CT system available at Universiti Sains Malaysia. Thus, the dual-energy CT capable of tissue characterization.  


2021 ◽  
Vol 11 (10) ◽  
pp. 4349
Author(s):  
Tianzhong Xiong ◽  
Wenhua Ye ◽  
Xiang Xu

As an important part of pretreatment before recycling, sorting has a great impact on the quality, efficiency, cost and difficulty of recycling. In this paper, dual-energy X-ray transmission (DE-XRT) combined with variable gas-ejection is used to improve the quality and efficiency of in-line automatic sorting of waste non-ferrous metals. A method was proposed to judge the sorting ability, identify the types, and calculate the mass and center-of-gravity coordinates according to the shading of low-energy, the line scan direction coordinate and transparency natural logarithm ratio of low energy to high energy (R_value). The material identification was satisfied by the nearest neighbor algorithm of effective points in the material range to the R_value calibration surface. The flow-process of identification was also presented. Based on the thickness of the calibration surface, the material mass and center-of-gravity coordinates were calculated. The feasibility of controlling material falling points by variable gas-ejection was analyzed. The experimental verification of self-made materials showed that identification accuracy by count basis was 85%, mass and center-of-gravity coordinates calculation errors were both below 5%. The method proposed features high accuracy, high efficiency, and low operation cost and is of great application value even to other solid waste sorting, such as plastics, glass and ceramics.


Author(s):  
Siqi Li ◽  
Guobao Wang

Combined use of PET and dual-energy CT provides complementary information for multi-parametric imaging. PET-enabled dual-energy CT combines a low-energy X-ray CT image with a high-energy γ -ray CT (GCT) image reconstructed from time-of-flight PET emission data to enable dual-energy CT material decomposition on a PET/CT scanner. The maximum-likelihood attenuation and activity (MLAA) algorithm has been used for GCT reconstruction but suffers from noise. Kernel MLAA exploits an X-ray CT image prior through the kernel framework to guide GCT reconstruction and has demonstrated substantial improvements in noise suppression. However, similar to other kernel methods for image reconstruction, the existing kernel MLAA uses image intensity-based features to construct the kernel representation, which is not always robust and may lead to suboptimal reconstruction with artefacts. In this paper, we propose a modified kernel method by using an autoencoder convolutional neural network (CNN) to extract an intrinsic feature set from the X-ray CT image prior. A computer simulation study was conducted to compare the autoencoder CNN-derived feature representation with raw image patches for evaluation of kernel MLAA for GCT image reconstruction and dual-energy multi-material decomposition. The results show that the autoencoder kernel MLAA method can achieve a significant image quality improvement for GCT and material decomposition as compared to the existing kernel MLAA algorithm. A weakness of the proposed method is its potential over-smoothness in a bone region, indicating the importance of further optimization in future work. This article is part of the theme issue ‘Synergistic tomographic image reconstruction: part 2’.


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.


2011 ◽  
Vol 1 (0) ◽  
pp. 285-287 ◽  
Author(s):  
Yuri NAKAGAWA ◽  
Jun KAWARABAYASHI ◽  
Ken-ichi WATANABE ◽  
Hideki TOMITA ◽  
Hiroyuki TOYOKAWA ◽  
...  

2016 ◽  
Vol 44 ◽  
pp. 1660213 ◽  
Author(s):  
J. Bendahan ◽  
W.G.J. Langeveld ◽  
V. Bharadwaj ◽  
J. Amann ◽  
C. Limborg ◽  
...  

In the present work, a method to direct the X-ray beam in real time to the desired locations in the cargo to increase penetration and reduce exclusion zone is presented. Cargo scanners employ high energy X-rays to produce radiographic images of the cargo. Most new scanners employ dual-energy to produce, in addition to attenuation maps, atomic number information in order to facilitate the detection of contraband. The electron beam producing the bremsstrahlung X-ray beam is usually directed approximately to the center of the container, concentrating the highest X-ray intensity to that area. Other parts of the container are exposed to lower radiation levels due to the large drop-off of the bremsstrahlung radiation intensity as a function of angle, especially for high energies (>6 MV). This results in lower penetration in these areas, requiring higher power sources that increase the dose and exclusion zone. The capability to modulate the X-ray source intensity on a pulse-by-pulse basis to deliver only as much radiation as required to the cargo has been reported previously. This method is, however, controlled by the most attenuating part of the inspected slice, resulting in excessive radiation to other areas of the cargo. A method to direct a dual-energy beam has been developed to provide a more precisely controlled level of required radiation to highly attenuating areas. The present method is based on steering the dual-energy electron beam using magnetic components on a pulse-to-pulse basis to a fixed location on the X-ray production target, but incident at different angles so as to direct the maximum intensity of the produced bremsstrahlung to the desired locations. The details of the technique and subsystem and simulation results are presented.


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