Suppression Of Scattering Effect In Optical CT Reconstruction

2005 ◽  
Author(s):  
Y. Onodera ◽  
Y. Kate ◽  
K. Shimizu
Keyword(s):  
Ct Reconstruction ◽  
Scattering Effect ◽  
Optical Ct

Optical CT reconstruction of 3D dose distributions using the ferrous-benzoic-xylenol (FBX) gel dosimeter

1998 ◽  
Vol 25 (9) ◽  
pp. 1741-1750 ◽  
Author(s):  
R. G. Kelly ◽  
K. J. Jordan ◽  
J. J. Battista
Keyword(s):  
Ct Reconstruction ◽  
Dose Distributions ◽  
Gel Dosimeter ◽  
Optical Ct

Maisonneuve fracture

2020 ◽  
Vol 99 (2) ◽  
pp. 77-85
Keyword(s):  
Open Reduction ◽  
Lower Leg ◽  
Fracture Dislocation ◽  
Deltoid Ligament ◽  
Ct Reconstruction ◽  
Distal Fibula ◽  
Ct Examination ◽  
Maisonneuve Fracture ◽  
Fibular Fracture ◽  
Wide Range

Introduction: Maisonneuve fracture (MF) is a generally known entity in ankle trauma. However, details about this type of injury can be found only rarely in the literature. For these reasons we have decided to perform a study on MF epidemiology and pathoanatomy. Methods: The group comprised 70 patients (47 men, 23 women), with the mean age of 48 years, who sustained an ankle fracture-dislocation involving the proximal quarter of the fibula. Ankle radiographs in three views and lower leg radiographs in two views were performed in all patients. A total of 59 patients underwent CT examination in three views, including 3D CT reconstruction in 49 of these patients. MRI was performed in 4 patients. Operative treatment was used in 67 patients; open reduction of the distal fibula into the fibular notch was opted for in 54 of them. Results: The highest MF incidence rate was recorded in the 5th decade in the whole group and in men, while in women the peak incidence was in the 6th decade. After the age of 50, the share of women significantly increased. In 64 cases, the fibular fracture was subcapital, and in 6 cases it involved the fibular head. In 24% of the patients, the fibular fracture was seen only in the lateral radiograph of the lower leg. Widening of the tibiofibular clear space was shown by radiographs in 40 cases. Posterior dislocation of the fibula (Bosworth fracture) and tibiofibular diastasis were recorded in 2 cases each. An injury to the anterior and posterior tibiofibular ligaments was found in all 54 patients with open reduction of the distal fibula. A fracture of the medial malleolus was identified in 27 cases (39%) and a complete lesion of the deltoid ligament in 36 cases (51%); in 7 cases (10%) the medial structures were intact. A fracture of the posterior malleolus occurred in 54 (77%) patients. Osteochondral fracture of the talar dome was diagnosed in 2 patients and compression of the articular surface of the distal tibia in the region of the fibular notch in 1 patient. Conclusion: Maisonneuve fracture includes a wide range of injuries both to bone and ligamentous structures of the ankle. Therefore, CT examination is an indispensable part of assessment of this type of fracture.

Digital Optical CT application to HVDC Earthing Line Fault measurements

2021 ◽  
pp. 1-1
Author(s):  
Allen H Rose ◽  
Richard Amano ◽  
Eric Hadley
Keyword(s):  
Optical Ct

Convergence and stability analysis of the half thresholding based few-view CT reconstruction

2020 ◽  
Vol 28 (6) ◽  
pp. 829-847
Author(s):  
Hua Huang ◽  
Chengwu Lu ◽  
Lingli Zhang ◽  
Weiwei Wang
Keyword(s):  
Noise Suppression ◽  
Reconstructed Image ◽  
Reference Image ◽  
Projection Data ◽  
Ct Reconstruction ◽  
Reconstruction Algorithms ◽  
Ill Posed ◽  
Thresholding Algorithm ◽  
The Stability ◽  
Well Posed

AbstractThe projection data obtained using the computed tomography (CT) technique are often incomplete and inconsistent owing to the radiation exposure and practical environment of the CT process, which may lead to a few-view reconstruction problem. Reconstructing an object from few projection views is often an ill-posed inverse problem. To solve such problems, regularization is an effective technique, in which the ill-posed problem is approximated considering a family of neighboring well-posed problems. In this study, we considered the {\ell_{1/2}} regularization to solve such ill-posed problems. Subsequently, the half thresholding algorithm was employed to solve the {\ell_{1/2}} regularization-based problem. The convergence analysis of the proposed method was performed, and the error bound between the reference image and reconstructed image was clarified. Finally, the stability of the proposed method was analyzed. The result of numerical experiments demonstrated that the proposed method can outperform the classical reconstruction algorithms in terms of noise suppression and preserving the details of the reconstructed image.

scholarly journals Validation of iterative CT reconstruction by inter and intra observer performance assessment of artificial lung foci

2020 ◽  
Vol 6 (3) ◽  
pp. 534-537
Author(s):  
Britta König ◽  
Nika Guberina ◽  
Hilmar Kühl ◽  
Waldemar Zylka
Keyword(s):  
Low Dose ◽  
Lung Cancer Screening ◽  
Artificial Lung ◽  
Observer Performance ◽  
Subjective Perception ◽  
Ct Reconstruction ◽  
Perfect Agreement ◽  
Observer Reliability ◽  
Iterative Ct Reconstruction ◽  
Extension Ring

AbstractWe investigate the suitability of statistical and model-based iterative reconstruction (IR) algorithm strengths and their influence on image quality and diagnostic performance in low-dose computer tomography (CT) protocols for lung-cancer screening procedures. We evaluate the inter- and intra-observer performance for the assessment of iterative CT reconstruction. Artificial lung foci shaped as spheres and spicules made from material with calibrated Hounsfield units were pressed within layered granules in lung lobes of an anthropomorphic phantom. Adaptively, a soft-tissue- and fat- extension ring were attached. The phantom with foci was scanned using standard high contrast, low-dose and ultra lowdose protocols. For reconstruction the IR algorithm ADMIRE at four different strength levels were used. Two ranking tests and Friedman statistics were performed. Fleiss k and modified Cohen’s kneywere used to quantify inter- and intra-observer performance. In conjunction with the standard lung kernel BL75 radiologists evaluated medium to high IR strength, with preference to S4, as suitable for lung foci detection. When varying reconstruction kernels the ranking became more random than with varying phantom diameter. The inter-observer reliability shows poor to slight agreement expressed by k<0 and k=0-0.20 . For the intra-observer reliability non- agreement with kney=0-0.20and moderate agreement with kney=0.60-0.79 for the first ranking test, and almost perfect agreement with kney>0.90 for the second ranking test was observed. In conclusion, our validation suggests radiological preference of medium to high iteration strengths, especially S4, for lung foci detection. An investigation of the correlation between diagnostic experience and the subjective perception of IR reconstructed CT images still needs to be investigated.

High Pitch Helical CT Reconstruction

2021 ◽  
pp. 1-1
Author(s):  
John W. Hayes ◽  
Juan Montoya ◽  
Adam Budde ◽  
Chengzhu Zhang ◽  
Yinsheng Li ◽  
...  
Keyword(s):  
Helical Ct ◽  
Ct Reconstruction ◽  
High Pitch
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