scholarly journals Cone-beam CT functional imaging method by using volume integral model

2018 ◽  
Vol 173 ◽  
pp. 03030
Author(s):  
Ying Qian ◽  
Boying Zheng
Keyword(s):  
Correlation Coefficient ◽  
Functional Imaging ◽  
Optimal Parameter ◽  
Optimization Method ◽  
Cone Beam ◽  
Integral Model ◽  
Projection Data ◽  
Imaging Method ◽  
Volume Integral ◽  
Dynamic Contrast Enhancement

In order to improve the precision of functional imaging of cone beam computed tomography (CBCT), this paper firstly uses the dynamic contrast enhancement tomography (DCE-CT) of the white rabbit as the measured object and establishes volume integral model to obtain the projection data. Then the optimization method is used to solve the optimal parameter pairs of the voxel time density curve (TDC). Finally, the results of the perfusion are obtained by the deconvolution method. The results show that the TDC correlation coefficient is 83.99% after, and the maximum of Spearman correlation coefficient of the perfusion parameter is 0.5125, and the projection time consumption is 7.633 seconds through the volume integral model. It can be seen that the volume integral model is closer to the real projection and it can obtain more accurate perfusion data.

scholarly journals FDK Half-Scan with a Heuristic Weighting Scheme on a Flat Panel Detector-Based Cone Beam CT (FDKHSCW)

2006 ◽  
Vol 2006 ◽  
pp. 1-8 ◽  
Author(s):  
Dong Yang ◽  
Ruola Ning
Keyword(s):  
Attenuation Coefficient ◽  
Weighting Function ◽  
Cone Beam Ct ◽  
Cone Angle ◽  
Weighting Scheme ◽  
Cone Beam ◽  
Projection Data ◽  
Imaging Method ◽  
Redundant Data ◽  
Beam Geometry

A cone beam circular half-scan scheme is becoming an attractive imaging method in cone beam CT since it improves the temporal resolution. Traditionally, the redundant data in the circular half-scan range is weighted by a central scanning plane-dependent weighting function; FDK algorithm is then applied on the weighted projection data for reconstruction. However, this scheme still suffers the attenuation coefficient drop inherited with FDK when the cone angle becomes large. A new heuristic cone beam geometry-dependent weighting scheme is proposed based on the idea that there exists less redundancy for the projection data away from the central scanning plane. The performance of FDKHSCW scheme is evaluated by comparing it to the FDK full-scan (FDKFS) scheme and the traditional FDK half-scan scheme with Parker's fan beam weighting function (FDKHSFW). Computer simulation is employed and conducted on a 3D Shepp-Logan phantom. The result illustrates a correction of FDKHSCW to the attenuation coefficient drop in the off-scanning plane associated with FDKFS and FDKHSFW while maintaining the same spatial resolution.

Combinatorial Optimization Method Based on Evaluation of Proximate Optimality Using Correlation Coefficient

2015 ◽  
Vol 135 (4) ◽  
pp. 466-467 ◽  
Author(s):  
Masahide Morita ◽  
Hiroki Ochiai ◽  
Kenichi Tamura ◽  
Junichi Tsuchiya ◽  
Keiichiro Yasuda
Keyword(s):  
Combinatorial Optimization ◽  
Correlation Coefficient ◽  
Optimization Method

scholarly journals A Method to Improve Electron Density Measurement of Cone-Beam CT Using Dual Energy Technique

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Kuo Men ◽  
Jian-Rong Dai ◽  
Ming-Hui Li ◽  
Xin-Yuan Chen ◽  
Ke Zhang ◽  
...  
Keyword(s):  
Electron Density ◽  
Cone Beam Ct ◽  
Density Measurement ◽  
Dual Energy ◽  
Cone Beam ◽  
Imaging Method ◽  
Basis Material ◽  
X Ray ◽  
Dual Energy Imaging ◽  
Set Up

Purpose. To develop a dual energy imaging method to improve the accuracy of electron density measurement with a cone-beam CT (CBCT) device.Materials and Methods. The imaging system is the XVI CBCT system on Elekta Synergy linac. Projection data were acquired with the high and low energy X-ray, respectively, to set up a basis material decomposition model. Virtual phantom simulation and phantoms experiments were carried out for quantitative evaluation of the method. Phantoms were also scanned twice with the high and low energy X-ray, respectively. The data were decomposed into projections of the two basis material coefficients according to the model set up earlier. The two sets of decomposed projections were used to reconstruct CBCT images of the basis material coefficients. Then, the images of electron densities were calculated with these CBCT images.Results. The difference between the calculated and theoretical values was within 2% and the correlation coefficient of them was about 1.0. The dual energy imaging method obtained more accurate electron density values and reduced the beam hardening artifacts obviously.Conclusion. A novel dual energy CBCT imaging method to calculate the electron densities was developed. It can acquire more accurate values and provide a platform potentially for dose calculation.

Measurement of cortical plate volume based on CBCT of frontal teeth in studies with retrusion and normality

2021 ◽  
pp. 17-21
Author(s):  
N. G. Meskhiya ◽  
I. S. Kopetskiy ◽  
I. A. Nikolskaya ◽  
D. A. Eremin ◽  
O. N. Kovaleva
Keyword(s):  
Orthodontic Treatment ◽  
Soft Tissues ◽  
Three Dimensions ◽  
Cone Beam ◽  
Cortical Plate ◽  
Imaging Method ◽  
New Approach ◽  
Accuracy Of Measurements ◽  
Bone Structures

Cone Beam Computed Tomography (CBCT) is the preferred imaging method for a comprehensive orthodontic examination. Thanks to the development of this technique, clinicians today can make most accurate measurements without fear of errors associated with projection distortion or localization of landmarks on radiographs. The quality of CBCT images gives to orthodontists the ability to analyze bone structures, teeth (even impacted teeth), and soft tissue in three dimensions. The accuracy of measurements of hard and soft tissues from CBCT images determines the accuracy of diagnosis and treatment planning. A fundamentally new approach has been proposed, which makes it possible to thoroughly study the bone tissue surrounding the tooth at the stages of planning orthodontic treatment. Аnalysis of radiation studies of patients with dentoalveolar anomalies was carried out to select the optimal treatment tactics and to control its effectiveness.

scholarly journals Cone-Beam Three-Dimensional Dental Volumetric Tomography in Dental Practice

2017 ◽  
Vol 7 (3) ◽  
pp. 62 ◽  
Author(s):  
Suzan Cangul ◽  
Ozkan Adiguzel
Keyword(s):  
Soft Tissues ◽  
Low Cost ◽  
Three Dimensional ◽  
Cone Beam ◽  
Imaging Method ◽  
Dental Practice ◽  
3 Dimensional ◽  
Scanning Time ◽  
Technological Advances ◽  
Native Speakers Of English

Imaging methods are of great importance for diagnosis and treatment in dentistry. With technological advances, great progress has been made in these methods. Over time, 3-dimensional (3-D) imaging has replaced 2-dimensional, thereby providing examination of objects in all directions. Of these methods, which play an important role in the clinical evaluation of patients, cone-beam computed tomography (CBCT) is the newest and most advanced imaging method. This method will revolutionize dental in comparison with conventional CT, it has several advantages, including a shorter scanning time, low radiation dose, low cost and the acquisition of high-resolution images. With 3-D imaging technology, this method has introduced the possibility of applying several procedures from diagnosis in the maxillofacial region to operative and surgical procedures. Although very clear results are not obtained from the imaging of soft tissues, the most important advantage of this technology is the capability of imaging hard and soft tissues together.   How to cite this article: Cangul S, Adiguzel O. Cone-Beam Three-Dimensional Dental Volumetric Tomography in Dental Practice. Int Dent Res 2017;7:62-70.  Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

A fast multiobjective optimization approach to S-duct scoop inlets design with both inflow and outflow

2018 ◽  
Vol 233 (9) ◽  
pp. 3381-3394
Author(s):  
Lifang Zeng ◽  
Dingyi Pan ◽  
Shangjun Ye ◽  
Xueming Shao
Keyword(s):  
Multiobjective Optimization ◽  
Total Pressure ◽  
Optimization Method ◽  
Navier Stokes ◽  
Integral Model ◽  
Optimization Approach ◽  
Navier Stokes Equation ◽  
Cross Sectional ◽  
Design Variables ◽  
Computational Fluid Dynamics Analysis

A fast multiobjective optimization method for S-duct scoop inlets considering both inflow and outflow is developed and validated. To reduce computation consumption of optimization, a simplified efficient model is proposed, in which only inflow region is simulated. Inlet pressure boundary condition of the efficient model is specified by solving an integral model with both inflow and outflow. An automated optimization system integrating the computational fluid dynamics analysis, nonuniform rational B-spline geometric representation technique, and nondominated sorting genetic algorithm II is developed to minimize the total pressure loss and distortion at the exit of diffuser. Flow field is numerically simulated by solving the Reynolds-averaged Navier–Stokes equation coupled with k–ω shear stress transport turbulence model, and results are validated to agree well with previous experiment. S-duct centreline shape and cross-sectional area distribution are parameterized as the design variables. By analyzing the results of a suggested optimal inlet chosen from the obtained Pareto front, total pressure recovery has increased from 97% to 97.4%, and total pressure distortion DC60 has decreased by 0.0477 (21.7% of the origin) at designed Mach number 0.7. The simplified efficient model has been validated to be reliable, and by which the time cost for the optimization project has been reduced by 70%.

A new weighting scheme for arc based circle cone-beam CT reconstruction

2021 ◽  
pp. 1-19
Author(s):  
Wei Wang ◽  
Xiang-Gen Xia ◽  
Chuanjiang He ◽  
Zemin Ren ◽  
Jian Lu
Keyword(s):  
Characteristic Function ◽  
Weighting Function ◽  
Cone Beam Ct ◽  
Reconstruction Algorithm ◽  
Cone Beam ◽  
Characteristic Functions ◽  
Projection Data ◽  
Ct Reconstruction ◽  
Scanning Angle ◽  
Beam Geometry

In this paper, we present an arc based fan-beam computed tomography (CT) reconstruction algorithm by applying Katsevich’s helical CT image reconstruction formula to 2D fan-beam CT scanning data. Specifically, we propose a new weighting function to deal with the redundant data. Our weighting function ϖ ( x _ , λ ) is an average of two characteristic functions, where each characteristic function indicates whether the projection data of the scanning angle contributes to the intensity of the pixel x _ . In fact, for every pixel x _ , our method uses the projection data of two scanning angle intervals to reconstruct its intensity, where one interval contains the starting angle and another contains the end angle. Each interval corresponds to a characteristic function. By extending the fan-beam algorithm to the circle cone-beam geometry, we also obtain a new circle cone-beam CT reconstruction algorithm. To verify the effectiveness of our method, the simulated experiments are performed for 2D fan-beam geometry with straight line detectors and 3D circle cone-beam geometry with flat-plan detectors, where the simulated sinograms are generated by the open-source software “ASTRA toolbox.” We compare our method with the other existing algorithms. Our experimental results show that our new method yields the lowest root-mean-square-error (RMSE) and the highest structural-similarity (SSIM) for both reconstructed 2D and 3D fan-beam CT images.

Recent Development of Cone-Beam X-Ray Microtomography at Sunyab

1997 ◽  
Vol 3 (S2) ◽  
pp. 1125-1126
Author(s):  
S.J. Pan ◽  
A. Shih ◽  
W.S. Liou ◽  
M.S. Park ◽  
G. Wang ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Imaging System ◽  
Tomographic Reconstruction ◽  
Ccd Camera ◽  
Test Sample ◽  
Glass Beads ◽  
Cone Beam ◽  
Projection Data ◽  
X Ray ◽  
Cooled Ccd

An experimental X-ray cone-beam microtomographic imaging system utilizing a generalized Feldkamp reconstruction algorithm has been developed in our laboratory. This microtomographic imaging system consists of a conventional dental X-ray source (Aztech 65, Boulder, CO), a sample position and rotation stage, an X-ray scintillation phosphor screen, and a high resolution slow scan cooled CCD camera (Kodak KAF 1400). A generalized Feldkamp cone-beam algorithm was used to perform tomographic reconstruction from cone-beam projection data. This algorithm was developed for various hardware configuration to perform reconstruction of spherical, rod-shaped and plate-like specimen.A test sample consists of 8 glass beads (approx. 800μm in diameter) dispersed in an epoxy-filled #0 gelatin capsule. One hundred X-ray projection images were captured equal angularly (at 3.6 degree spacing) by the cooled CCD camera at a of 1317×967 (17×17mm2) pixels with 12-bit dynamic range. Figure 1 shows a 3D isosurface rendering of the test sample. The eight glass beads and trapped air bubbles (arrows) in the epoxy resin (e) are clearly visible.

Sign in / Sign up

Export Citation Format

Share Document