Journal of X-Ray Science and Technology - Volume 26, issue 1
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Journal of X-Ray Science and Technology is an international journal designed for the diverse community (biomedical, industrial and academic) of users and developers of novel x-ray imaging techniques. The purpose of the journal is to provide clear and full coverage of new developments and applications in the field.
Areas such as x-ray microlithography, x-ray astronomy and medical x-ray imaging as well as new technologies arising from fields traditionally considered unrelated to x rays (semiconductor processing, accelerator technology, ionizing and non-ionizing medical diagnostic and therapeutic modalities, etc.) present opportunities for research that can meet new challenges as they arise.
Abstract: BACKGROUND: Recent advances in photon counting detection technology have led to significant research interest in X-ray imaging. OBJECTIVE: As a tutorial level review, this paper covers a wide range of aspects related to X-ray photon counting detector characterization. METHODS: The tutorial begins with a detailed description of the working principle and operating modes of a pixelated X-ray photon counting detector with basic architecture and detection mechanism. Currently available methods and techniques for charactering major aspects including energy response, noise floor, energy resolution, count rate performance (detector efficiency), and charge sharing effect of photon counting detectors are…comprehensively reviewed. Other characterization aspects such as point spread function (PSF), line spread function (LSF), contrast transfer function (CTF), modulation transfer function (MTF), noise power spectrum (NPS), detective quantum efficiency (DQE), bias voltage, radiation damage, and polarization effect are also remarked. RESULTS: A cadmium telluride (CdTe) pixelated photon counting detector is employed for part of the characterization demonstration and the results are presented. CONCLUSIONS: This review can serve as a tutorial for X-ray imaging researchers and investigators to understand, operate, characterize, and optimize photon counting detectors for a variety of applications.
Keywords: Photon counting detector, detector characterization, energy response calibration, noise floor, energy resolution, count rate performance, charge sharing effect
Abstract: Nowadays, huge number of mammograms has been generated in hospitals for the diagnosis of breast cancer. Content-based image retrieval (CBIR) can contribute more reliable diagnosis by classifying the query mammograms and retrieving similar mammograms already annotated by diagnostic descriptions and treatment results. Since labels, artifacts, and pectoral muscles present in mammograms can bias the retrieval procedures, automated detection and exclusion of these image noise patterns and/or non-breast regions is an essential pre-processing step. In this study, an efficient and automated CBIR system of mammograms was developed and tested. First, the pre-processing steps including automatic labelling-artifact suppression, automatic pectoral muscle removal,…and image enhancement using the adaptive median filter were applied. Next, pre-processed images were segmented using the co-occurrence thresholds based seeded region growing algorithm. Furthermore, a set of image features including shape, histogram based statistical, Gabor, wavelet, and Gray Level Co-occurrence Matrix (GLCM) features, was computed from the segmented region. In order to select the optimal features, a minimum redundancy maximum relevance (mRMR) feature selection method was then applied. Finally, similar images were retrieved using Euclidean distance similarity measure. The comparative experiments conducted with reference to benchmark mammographic images analysis society (MIAS) database confirmed the effectiveness of the proposed work concerning average precision of 72% and 61.30% for normal & abnormal classes of mammograms, respectively.
Abstract: In practice, mis-calibrated detector pixels give rise to wide and faint ring artifacts in the reconstruction image of the In-line phase-contrast computed tomography (IL-PC-CT). Ring artifacts correction is essential in IL-PC-CT. In this study, a novel method of wide and faint ring artifacts correction was presented based on combining TV-L1 model with guided image filtering (GIF) in the reconstruction image domain. The new correction method includes two main steps namely, the GIF step and the TV-L1 step. To validate the performance of this method, simulation data and real experimental synchrotron data are provided. The results demonstrate that TV-L1 model with…GIF step can effectively correct the wide and faint ring artifacts for IL-PC-CT.
Abstract: Based on X-ray diffraction (XRD) pattern of coal, an empirical model for judging the coalification degree is used to calculate the ratio of the 002 peak height to the Full width at half maximum (FWHM). However, the existing models are often simpler and more suitable for judgment of the medium and low rank coal, while are not feasible in determination of high rank coal. In order to address this issue, the objective of this study is to establish a new modified mathematical model based on optimization of the existing empirical models. Through the calculation of Bragg equation, it demonstrates that…the low-angle region (2θ = 3–10°) in the XRD pattern reflects the information of micropore in coal with a diameter of (0.884–2.94) nm. Accordingly, its diffraction intensity corresponds to the porosity rate in coal. As a result, the modified mathematical model has been established for characterizing the coalification degree by introducing the variation of porosity rate with the coal ranks creatively. The synergistic effects of the change regulation of organic matter peak and the porosity rate with coal rank ensure the accuracy of the model. Furthermore, the good stability and high reliability of new model are verified through the recalculation of a total of 14 coal samples. Study results demonstrated that the new method enabled to determine coal rank more conveniently and accurately in the industrial production.
Abstract: OBJECTIVES: This work aims to explore more accurate pixel-driven projection methods for iterative image reconstructions in order to reduce high-frequency artifacts in the generated projection image. METHODS: Three new pixel-driven projection methods namely, small-pixel-large-detector (SPLD), linear interpolation based (LIB) and distance anterpolation based (DAB), were proposed and applied to reconstruct images. The performance of these methods was evaluated in both two-dimensional (2D) computed tomography (CT) images via the modified FORBILD phantom and three-dimensional (3D) electron paramagnetic resonance (EPR) images via the 6-spheres phantom. Specifically, two evaluations based on projection generation and image reconstruction were performed. For projection generation,…evaluation was using a 2D disc phantom, the modified FORBILD phantom and the 6-spheres phantom. For image reconstruction, evaluations were performed using the FORBILD and 6-spheres phantom. During evaluation, 2 quantitative indices of root-mean-square-error (RMSE) and contrast-to-noise-ratio (CNR) were used. RESULTS: Comparing to the use of ordinary pixel-driven projection method, RMSE of the SPLD based least-square algorithm was reduced from 0.0701 to 0.0384 and CNR was increased from 5.6 to 19.47 for 2D FORBILD phantom reconstruction. For 3D EPRI, RMSE of SPLD was also reduced from 0.0594 to 0.0498 and CNR was increased from 3.88 to 11.58. In addition, visual evaluation showed that images reconstructed in both 2D and 3D images suffered from high-frequency line-shape artifacts when using the ordinary pixel-driven projection method. However, using 3 new methods all suppressed the artifacts significantly and yielded more accurate reconstructions. CONCLUSIONS: Three proposed pixel-driven projection methods achieved more accurate iterative image reconstruction results. These new and more accurate methods can also be easily extended to other imaging modalities. Among them, SPLD method should be recommended to 3D and four dimensional (4D) EPR imaging.
Keywords: Accurate pixel-driven projection, iterative image reconstruction, computed tomography, electron paramagnetic resonance imaging
Abstract: Double aortic arch (DAA) is a rare congenital anomaly associated with the formation of a vascular ring. Patients with DAA commonly suffer from complications caused by intracardiac and extracardiac malformations and different degrees of airway stenosis. Multislice computed tomographic angiography (MSCTA) is an intuitive and effective medical imaging technique in clinical diagnosis of DAA. MSCTA can accurately manifest the aortic arch and the course of the descending aorta and airway stenosis in three-dimension (3D). It is important to diagnose and make an operative plan for DAA. In this paper, we present a case of DAA diagnosed by MSCTA with 3D-static…images and rotated reconstruction images and performed a mini-review.
Keywords: MSCTA, 3D reconstruction images, double aortic arch, diagnosis
Abstract: Maxillofacial injuries can be complex and are clinically important due to their functional and cosmetic significance. Maltreated and missed fractures might cause deformity of the face; thus, accurate evaluation of the fracture provided by X-ray images is critical. In this study, we explore the application of cone-beam computed tomography (CBCT) for diagnosis of severe maxillofacial traumas. A patient with a complex fracture that affects the maxilla, mandible, wall of the maxillary sinus, zygoma, zygomatic arch and nasal bone was diagnosed using 3D reconstruction of CBCT images. This diagnostic approach provides detailed information obtained by static images and a systematic model…with unique advantages for the following pre-surgical evaluation, surgical treatment and prognostic assessment of complex maxillofacial fractures.
Keywords: CBCT, 3D reconstruction images, dental medicine application, maxillofacial fracture
Abstract: BACKGROUND: Congenital hydronephrosis is often caused by aberrant renal vessel and it is difficult to be diagnosed and treated at the early stage due to lack of the significant symptoms. Although current medical diagnosis tools are widely used, the aberrant renal vessel cannot be displayed very well in the images. OBJECTIVE: To investigate whether applying computed tomography (CT) angiography with 3D reconstruction can improve efficacy in diagnose of this congenital hydronephrosis. MATERIALS AND METHODS: A male patient of 18 years old was diagnosed as hydronephrosis of left kidney. A CT angiography with 3D reconstruction was evaluated…in diagnosis of the prenatal hydronephrosis compared to ultrasound (US) and intravenous urogram (IVU). RESULTS: US and IVU images were able to display the dilation of left pelvic and the dilated calyces, and the thinner of renal parenchyma on the left kidney (Grade II-IV), but failed to detect the causing of hydro-nephrosis. CT angiography with 3D reconstruction provided accurate images of the dilated renal pelvic, upper segment of the ureter, and an aberrant vessel bundle overcrossing at the left renal pelvic-ureter junction as well. The aberrant vessel could be revealed during surgery. CONCLUSIONS: A CT angiography with 3D reconstruction provides a more accurate diagnostic approach for the congenital hydronephrosis caused by aberrant renal vessel. Thus, it can offer surgeons very important information in the pre-surgery planning.
Keywords: Hydronephrosis, aberrant vessel, 3D CT angiography
Abstract: Cone beam computed tomography (CBCT) has obvious advantages over regular radiography in diagnosis of complex diseases. Objective of this study is to report a case of a mandibular jaw ameloblastoma recurring cyst, which represents a benign tumor of odontogenic epithelium, using CBCT imaging technology. CBCT examination of the patient suffering with recurrent lower jaw cyst (relapsing four years after surgery) showed a decrease in irregular bone density and appearance of a honeycomb pattern (3.5 cm×2.5 cm×1.8 cm) in the right lower jaw. This suggests that the lesion is more likely to be an ameloblastoma. Preoperative tissue biopsy and pathological examination of surgical sample…confirmed the diagnosis. Surgical resection of the diseased tissue and autogenous bone grafting in the mandible was performed. Postoperative CBCT examination showed that the bone defect healed well, without recurrence of the tumor 22 months postoperatively. In conclusion, the rotated 3D CBCT images clearly displays the exact size, location, borders and internal changes of the tumor in the jaw cyst itself and the adjacent tissues. Thus, the dental CBCT allows clinicians to better evaluate lesions, leading to better treatment outcomes.
Abstract: Rosai-Dorfman disease (RDD) is a rare histiocytic disorder of unclear etiology, which commonly presented with the enlargement of lymph nodes of the neck and the head. Here, we report an unusual case of 77-year-old male patient presenting with left kidney lesion with several small enlarged lymph nodes around the abdominal aorta. The diagnosis of left kidney cancer was suspected and the patient underwent left laparoscopic exploration and lymph node biopsy. Only saponification of the renal surrounding fat and enlargement of the left renal pedicle and 5 abdominal aortic lymph nodes were found; no kidney cancer was found. Surrenalectomy and lymphadenectomy…dissection were then performed and the left kidney was retained. Intraoperative frozen and postoperative pathology indicates Rosai-Dorfman disease. RDD with kidney involvement is uncommon, and its x-ray imaging appearances are atypical, and often resemble kidney cancer leading to kidney loss. A systematic literature review was also performed to investigate the x-ray imaging and treatment features of this disease.
Abstract: OBJECTIVE: This study aimed to investigate the application of 3D computed tomography (CT) angiography with a novel post-processing technique in diagnosis of malignant bone tumors in children. METHODS: Twenty-seven pediatric patients (15 males and 12 females; average age: 10±3.4 years old, with a range from 2 months to 14 years old) with suspected bone tumors were evaluated histopathologically using 3D CT angiography and a multislice scanner. CT angiography image data were analyzed with a novel post-processing technique that included separating, fusing opacifying false-coloring, and volume rendering. RESULTS: Among 27 cases, 20 (74%) osteosarcoma, 6 (22%) Ewing’s…sarcoma, and 1 (4%) non-Hodgkin lymohoma were diagnosed by histological examination of surgical specimens. The tumor features, including size, location, invasion into the adjacent tissue as well as distant metastases, were clearly visualized with the regular volume rendering method and rotational and stereoscopical videos. The post-processing technique provided the reconstructed structure images without any overlap or shelter independently and collectively. Special colors represented different tissue structures, aiding in identification of various anatomical structures and pre-surgical planning. CONCLUSIONS: Compared to traditional 3-D CT methods, 3-D CT angiography with rotational and stereoscopical videos provides more detailed information of bone tumor lesions. It offers a superior and effective imaging technique in pediatric patients with malignant bone tumors.
Abstract: Lymphoepithelial carcinoma (LEC) is an uncommon malignant neoplasm. Due to the complicated anatomical structure of the human head, standard imaging modalities including ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) scan remain limited in detection of salivary tumors. We used three-dimensional computed tomography angiography (3D-CT angiography) for the assessment and pre-operative surgical planning of facial fractures of a case with LEC. The study results demonstrated that 3D-CT angiography provided an insightful approach to preoperative evaluation in the treatment of salivary tumors.
Keywords: Lymphoepithelial carcinoma, parotid gland, three dimensional computed
Abstract: Despite common injury caused by snakebite, snakebite-induced ischemic stroke is rare. We reported on a patient who incurred a large cerebral infarction after being bitten by a Deinagkistrodon acutus, one of the most poisonous snakes in the southwestern of China. Applying 3D computed tomography (CT) of head combined with cerebral angiography examinations showed a large cerebral infarction, hernia in the right brain, developmental abnormalities of the right middle cerebral artery and cerebral artery of right brain. In conclusion, head CT imaging combined with cerebral angiography provides an efficient approach in diagnosis of stroke caused by snakebites.
Keywords: Snakebite, Deinagkistrodon acutus, cerebral infarction, 3D head computed tomography (CT)