Journal of X-Ray Science and Technology - Volume 21, issue 3

Authors: Li, Chen | Liu, Jie

Article Type: Research Article

Abstract: 4D CT, which could locate the position of the movement of the tumor in the entire respiratory cycle and reduce image artifacts effectively, has been widely used in making radiation therapy of tumors. The current 4D CT methods required external surrogates of respiratory motion obtained from extra instruments. However, respiratory signals recorded by these external makers may not always accurately represent the internal tumor and organ movements, especially when irregular breathing patterns happened. In this paper …we have proposed a novel automatic 4D CT sorting algorithm that performs without these external surrogates. The sorting algorithm requires collecting the image data with a cine scan protocol. Beginning with the first couch position, images from the adjacent couch position are selected out according to spatial continuity. The process is continued until images from all couch positions are sorted and the entire 3D volume is produced. The algorithm is verified by respiratory phantom image data and clinical image data. The primary test results show that the 4D CT images created by our algorithm have eliminated the motion artifacts effectively and clearly demonstrated the movement of tumor and organ in the breath period. Show more

Keywords: 4D CT, image sorting, spatial continuity

DOI: 10.3233/XST-130381

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 3, pp. 323-333, 2013

Authors: He, Peng | Yu, Hengyong | Bennett, James | Ronaldson, Paul | Zainon, Rafidah | Butler, Anthony | Butler, Phil | Wei, Biao | Wang, Ge

Article Type: Research Article

Abstract: Experiments were performed to evaluate the energy-discriminative performance of a spectral (multi-energy) micro-CT system. The system, designed by MARS (Medipix All Resolution System) Bio-Imaging Ltd. (Christchurch, New Zealand), employs a photon-counting energy-discriminative detector technology developed by CERN (European Organization for Nuclear Research). We used the K-edge attenuation characteristics of some known materials to calibrate the detector's photon energy discrimination. For tomographic analysis, we used the compressed sensing (CS) based ordered-subset simultaneous algebraic …reconstruction techniques (OS-SART) to reconstruct sample images, which is effective to reduce noise and suppress artifacts. Unlike conventional CT, the principal component analysis (PCA) method can be applied to extract and quantify additional attenuation information from a spectral CT dataset. Our results show that the spectral CT has a good energy-discriminative performance and provides more attenuation information than the conventional CT. Show more

Keywords: Energy-discriminative performance, spectral CT, K-edge imaging, compressive sensing, iterative reconstruction, principal component analysis

DOI: 10.3233/XST-130382

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 3, pp. 335-345, 2013

Authors: Block, Robert C. | Geuther, Jeffrey A. | Methe, Brian | Barry, Devin P. | Leinweber, Gregory

Article Type: Research Article

Abstract: The interpretation of neutron cross section experiments depends upon an in-depth knowledge of the physical characteristics of the target sample. An x-ray image of an encapsulated metallic Eu sample used in a neutron cross section measurement showed a very non-uniform thickness as well as holes in the sample. In light of this problem it was found necessary to determine the thickness distribution in four thin metallic Eu samples without disturbing the encapsulation (and exposing the Eu …to air). All four Eu samples were subsequently x-rayed along with a Sm step wedge. The gray levels in the Eu images were then compared to the Sm gray levels and, taking into account differences in the x-ray absorption and density of Eu and Sm, the sample thickness distributions were obtained for each Eu sample. This work demonstrates that a step wedge can be used to calibrate x-ray images to a thickness scale, and allows the thickness variation of the samples to be represented in a simple probability table for incorporation into the analysis of neutron experiments. Show more

Keywords: X-ray method, encapsulated samples, sample thickness, neutron cross section samples

DOI: 10.3233/XST-130383

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 3, pp. 347-355, 2013

Authors: Park, Hyoung Suk | Choi, Jae Kyu | Park, Kyung-Ran | Kim, Kyung Sang | Lee, Sang-Hwy | Ye, Jong Chul | Seo, Jin Keun

Article Type: Research Article

Abstract: There is increasing demand in the field of dental and medical radiography for effective metal artifact reduction (MAR) in computed tomography (CT) because artifact caused by metallic objects causes serious image degradation that obscures information regarding the teeth and/or other biological structures. This paper presents a new MAR method that uses the Laplacian operator to reveal background projection data hidden in regions containing data from metal. In the proposed method, we attempted to decompose …the projection data into two parts: data from metal only (metal data), and background data in the absence of metal. Removing metal data from the projections enables us to perform sparsity-driven reconstruction of the metal component and subsequent removal of the metal artifact. The results of clinical experiments demonstrated that the proposed MAR algorithm improves image quality and increases the standard of 3D reconstruction images of the teeth and mandible. Show more

Keywords: Metal artifact reduction, dental X-ray CT, poisson equation, compressed sensing, sparsity

DOI: 10.3233/XST-130384

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 3, pp. 357-372, 2013

Authors: Zhang, Jie | Zhang, Da

Article Type: Research Article

Abstract: Image performance of a cone beam O-arm system with the use of a Varian flat panel detector (PaxScan 4030CB) was evaluated. Modulation Transfer Function (MTF), Noise Power Spectrum (NPS), and tube output characteristics were measured. Image quality measurements were performed with a CATPHAN 424 phantom using a 120 kVp beam filtered with 1 mm Al and 0.1 mm Cu and three preset protocols at different exposure levels. The CPT445 Module was used to measure MTF. Water …phantom images were used to calculate NPS. Then the NPS was normalized by dividing the square of the mean signal. The Photon fluence at each exposure (q) was estimated using the SpekCalc. The MTF indicates that the reconstruction filter of the O-arm is overenhancing, meaning that it yields values greater than unity. The system has a 10% MTF at 0.45 mm. The NPS shows the low frequency structured noise. The evaluation of image performance of the O-arm imaging system helps its future improvements and clinical applications. Show more

Keywords: O-arm, cone-beam computed tomography (CT), modulation transfer function (MTF), noise power spectrum (NPS), performance, flat panel detector (FPD)

DOI: 10.3233/XST-130385

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 3, pp. 373-380, 2013

Authors: Torrisi, L. | Italiano, A. | Cutroneo, M. | Gentile, C. | Torrisi, A.

Article Type: Research Article

Abstract: The investigation on the differences occurring in the manufacture of silver coins allows to get information on their elemental composition and represents a powerful support to the methodology to identify the producing technologies, workshops being also instrumental to distinguish between original and counterfeit ones. Aim of the present work is to study recent and old silver coins through non-destructive X-Ray Fluorescence (XRF) analysis. The XRF was applied to extend the analysis to the deepest layers of …the coins; for surface layers an X-ray tube or an electron beam were employed to induce the atom fluorescence to obtain information on the surface elemental composition. Moreover, a detailed study has been performed to evaluate the influence of the surface curvature on the measurement, by deducing a proper corrective factor to keep into account in the data analysis. The elemental atomic composition was measured for each coin, mainly by means of the X-ray tube excitation for the bulk and the electron Scanning Electron Microscope (SEM) microbeam probe for the surface patina analysis. Ionization was induced by an X-ray tube using an Ag anode for the bulk and by an electron microprobe for the surface composition. X-ray detection was performed by using a semiconductor Si device cooled by a Peltier system. The Ag L-lines X-ray yield is affected by coin surface morphology and geometry. The comparison between coin spectra and standard samples, shows that the Ag quantitative analysis is influenced by error of the atomic concentration lower that 10%. Show more

Keywords: Silver coins, X-ray fluorescence, patina, corrective factor

DOI: 10.3233/XST-130389

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 3, pp. 381-390, 2013

Authors: Xu, Chuanliang | Zhang, Zhensheng | Ye, Huamao | Wu, Chengyao | Zhang, Chao | Zhang, Yuanyuan | Wang, Yang | Cao, Zhi | Wang, Huiqing | Xu, Weidong | Pan, Anyin | Wei, Rongchao | Zeng, Shuxiong | Sun, Yinghao

Article Type: Research Article

Abstract: OBJECTIVE: Fibroepithelial polyps of ureter prolapsing into the bladder are a rare urological condition. We report the imaging findings and our experience with endoscopic treatment for ureteral fibroepithelial polyps prolapsing into the bladder. PATIENTS AND RESULTS: Four patients with frank pain and hematuria were enrolled. Intravenous urography and computed tomography revealed a ureteral mass with filling defects in affected ureter and mild hydronephrosis. Endoscopic examination showed ureteral polyps prolapsing in the bladder. The …histopathologic diagnosis on 4 cases was benign fibroepithelial polyps of ureter. The largest polyps (from 4–10 cm in length) were successfully resected and vaporized by Holmium: YAG laser. A double-pigtail ureteral stent at 7F was placed and left for 6 weeks after the procedure. Neither recurrence nor ureter stricture was observed after up to 12 years of follow-up. CONCLUSIONS: Ureteral malignancy must be excluded in cases where a ureteral mass is detected. Endoscopic management is recommended to minimize morbidity and complications in treatment of ureteral fibroepithelial polyps that prolapse into the bladder. Show more

Keywords: Ureter lesion, benign tumor, laser, endoscopic treatment

DOI: 10.3233/XST-130390

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 3, pp. 393-399, 2013

Authors: Zeng, Dan | Liu, Guihua | Sun, Xiangzhou | Zhuang, Wenquan | Zhang, Yuanyuan | Guo, Wenbo | Yang, Jianyong | Chen, Wei

Article Type: Research Article

Abstract: The goal of this study is to evaluate the feasibility and efficacy of percutaneous transarterial embolization for the treatment of serious renal hemorrhage after renal biopsy. Nine patients with renal hemorrhage had frank pain and gross hematuria as main symptoms after renal biopsy. Intrarenal arterial injuries and perinephric hematoma were confirmed by angiography in all cases. The arterial injuries led to two types of renal hemorrhage, Type I: severe renal injure or intrarenal renal artery rupture …(n=5), with contrast medium spilling out of the artery and spreading into renal pelvis or kidney capsule in angiography; Type II, pseudo aneurysm or potential risk of intrarenal artery injure (n=4), where contrast medium that spilled out of intraartery was retained in the parenchyma as little spots less than 5 mm in diameter in angiography. Transcatheter superselective intrarenal artery embolization was performed with coils or microcoils (Type I intrarenal artery injure) and polyvinyl alcohol particles (Type II injure). The intrarenal arterial injuries were occluded successfully in all patients. Light or mild back or abdominal pain in the side of the embolized kidney was found in three patients following embolization procedures and disappeared 3 days later. Serum creatinine and perinephric hematoma were stable, and gross hematuresis stopped immediately (n=4) or 3–5 days (n=3) after embolization. In conclusions, transcatheter superselective intrarenal artery embolization as a minimally invasive therapy is safe and effective for treatment of serious renal hemorrhage following percutaneous renal biopsy. Show more

Keywords: Embolization, kidney, biopsy, hemorrhage

DOI: 10.3233/XST-130391

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 3, pp. 401-407, 2013

Authors: Ji, Qiao | Liu, Guihua | Sun, Xiangzhou | Liu, Guangjian | Lu, Mingde | Xie, Xiaoyan | Xu, Ming | Zhang, Yuanyuan | Zheng, Shuguang

Article Type: Research Article

Abstract: The purpose of this study was to distinguish passive retention of microbubbles in liver sinusoids from active intracellular retaining, and to provide further evidence of post vascular liver specific phase of perflubutane microbubble contrast-enhanced ultrasound for potential use in the detection of focal liver lesions. Fifty-four rats were divided into three groups: saline group (G1, as a control, n=6), sulphur hexafluoride microbubble group (G2, n=24) and perflubutane microbubble group (G3, n=24). The livers were perfused …at 2, 5, 10 and 20 min after injection of perflubutane or sulphur hexafluoride gas-filled microbubbles or normal saline. Changes in contrast-enhanced images within the liver were quantified. After perfusion, the echogenicity of the liver in the saline group increased from −49.44 ± 0.08 dB to − 44.37 ± 1.02 dB (p< 0.05). In G2, the enhancement decreased significantly after perfusion at 2 and 5 min, and increased at 10 and 20 min (all p< 0.05). In G3, the enhancement decreased from −18.05 ± 2.28 dB to − 26.76 ± 1.69 dB only at 2 min after perfusion (p < 0.05). Perflubutane microbubbles provided a post vascular liver specific phase on contrast-enhanced ultrasound, which could begin as early as 5 min after administration of the contrast agent in rats. This study suggests that perflubutane microbubbles could result in a liver specific phase and provide valuable information for diagnosis and detection of focal liver lesions which may improve the efficiency of contrast-enhanced ultrasound in clinical diagnoses of liver diseases. Show more

Keywords: Ultrasound, contrast agent, phase, liver

DOI: 10.3233/XST-130392

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 3, pp. 409-418, 2013

Authors: Shao, Qiang | Xu, Jianfeng | Adams, Tamara | Tao, Sha | Cui, Yon | Shen, Hua | Cao, Wenzhou | Xie, Jianjun | Fan, Youzhang | Zhang, Yuanyuan | Huang, Min

Article Type: Research Article

Abstract: PURPOSE: To perform a retrospective study to compare the efficiency, safety and costs using aspiration-sclerotherapy with 95% ethanol vs. laparoscopic decortications in management of symptomatic simple renal cysts. MATERIALS AND METHODS: Patients with simple renal cysts (diamante ⩾ 4 cm) were recruited from our hospital between October 2008 and October 2012. A total of 986 patients (Group 1) underwent aspiration-sclerotherapy with 95% ethanol and 208 patients (Group 2) underwent laparoscopic decortication. All patients were …followed up with ultrasonography or computerized tomography (CT) for one year. Regression rates, recurrence rates and costs were compared. RESULTS: Similarity in symptoms (back pain, cloudy urine or mass in abdomen), renal cyst size, and cyst distribution, complete regression rate after treatment between the two groups; A higher recurrence rate, but shorter procedure times and lower cost in Group 1 compared to Group 2. The procedures used for both groups were safe and had minimum complications. CONCLUSION: Aspiration-sclerotherapy, as well as laparoscopic decortication are effective and safe therapy for symptomatic simple renal cysts. Aspiration-sclerotherapy is more suitable for medium size of renal cysts, while Laparoscopic decortication is superior to the cysts in large sizes. Show more

Keywords: Symptomatic simple renal cysts, aspiration-sclerotherapy, laparoscopic decortication, 95% ethanol

DOI: 10.3233/XST-130393

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 3, pp. 419-428, 2013