CT理论与应用研究

Resistivity Tomography and Calculation of Stability in Surveying Excavated-Empty-Area and Inclined Shaft Tunnels in Coal Mine

LI Qing-lin, XIE Ru-yi, WANG Lan-fu, QIN Jian-zeng, ZHANG Jian-zhi

2005, 14(3): 1-7.

Abstract(729) PDF(0)

Abstract:
The excavated-empty-area and the inclined shaft trunnels were surveyed with Z-D resistivity tomography in YueJin Power plant with 2×50MW/year of Yima Coal Mining Industry Group in Henan Province. The places of the excavated-empty-area and it’s influence range, and the inclined shaft tunnels were determined. Z-D images of the resistivity tomography show generally anomalous high-resistivity closed circles, which suggests that there is no water in the excavated-empty-area and in the inclined shaft tunnels. Should there be water, the anomaly would manifest as low-resistivity closed circles. Moreover the stability and safety of the inclined shaft tunnels are analyzed and calculated based on the parameters of geological structures, stratigraphic configuration and ground buildings. Our studied results indicate that ① the inclined shaft tunnels have strong influence on the main monitored-control building, and the building is instable and unsafe must be reinforced; ② the main workshop does not be affected and is stable.

3D imaging CT and multi-phase Driving -substitute Analytical System for rock-core and Oil

SHENG Qiang, SHI Xiao-le, LIU Wei-fu, XING Yi-liang

2005, 14(3): 8-12.

Abstract(778) PDF(0)

Abstract:
“The 3D imaging CT and multi-phase driving-substitute for rock-core containing oil analytical system” is introduced in this paper, provide corresponding software for constructing these system. These research content include: 1, the flat surface 2D image processing part; 2, DR experiment compute the saturation rate problem; 3, the 3D real body reconstruction.

Comparison Analysis of Digital Radiography(DR) and X-ray Film Imaging

YUAN Ming-kai, LIU Li

2005, 14(3): 13-17.

Abstract(782) PDF(3)

Abstract:
In this article,principles of digital radiography and X-ray film imaging are introduced. Characteristics of these two methods are compared with each other,the further developing trend of X-ray imaging methods is discussed.

Fan-beam Filtered Back-projection (FFBP) Algorithm Considering Practical Place of Projection Imaging Plane

PEI Xiao-dong, ZHANG Quan-hong

2005, 14(3): 18-23.

Abstract(903) PDF(0)

Abstract:
In the theoretic formula of fan-beam filtered back projection (FFBP) algorithm, the projection imaging plane lies on the center of rotation, but in practical CT scan system, it keeps the center at a distance. With respect to this problem, this paper proposes an improved fan-beam filtered back projection (IFFBP) algorithm, and compares reconstruction quality of FFBP with IFFBP. The results of computer simulation and experiment validate IFFBP algorithm.

The Review of Reasons and Correction Methods for Artifacts in ICT Images

GU Jian-wei, ZHANG Li, CHEN Zhi-qiang, XING Yu-xiang, GAO He-wei

2005, 14(3): 24-28.

Abstract(831) PDF(5)

Abstract:
X-ray CT plays a great role in industrial non-destructive tests, medical fields, and public security, etc. In practice the reconstructed images have different kinds of artifacts. In this paper, kinds of reasons and correction methods of artifacts are summarized. Additionally, some comparison and discussion on these methods in recent literatures is done.

New Developments of exact Cone-beam CT Reconstruction Algorithms

CHEN Zhi-qiang, LI Liang, KANG Ke-jun, ZHANG Li

2005, 14(3): 65-70.

Abstract(561) PDF(3)

Abstract:
The international meeting on fully three-dimensional image reconstruction meeting in radiology and nuclear medicine was hold in July 2005, USA. It is one of the most famous meetings in CT, PET and SPECT image reconstruction field. This paper introduces some novel developments in PET, SPECT and CT imaging upon this meeting. According to our interest, we focus on exact cone-beam CT reconstruction including Minimum data filtered-backprojection algorithm (MD-FBP), the R-line algorithm and so on. In the end, we discuss the different advantages of the above two exact algorithms and research prospects in cone-beam reconstruction.

Structure and Standard of Image Resolution Test Card

ZENG Xiang-zhao

2005, 14(3): 29-34.

Abstract(652) PDF(1)

Abstract:
The resolution test card is objective describing the ray film resolution actually and be used for digital radiography resolution examination system (Including X-ray image film resolution), which is the important tool for product quality index, This text shows the structure of image resolution test card and just construction of the profession standard《Explanation for Ray’s resolution examination test card 》 and its progress circumstance.

Application of high Energy Industrial Computed Tomography In Testing Solid Rocket Engine

DING Guo-fu

2005, 14(3): 35-39.

Abstract(692) PDF(2)

Abstract:
Along with the technology of high energy ICT(Industrial Computed Tomography) developing in China, this intuitionistic,credible and quick nondestructive testing technique is applied to testing rocket engine gradually.This thesis mainly described application situtition,application scope and testing technology feature for high energy ICT(Industrial Computed Tomography) in testing solid rocket engine.

Research on Subvoxel Surface Detection Algorithms of ICT Images

WANG Kai, ZHANG Ding-hua, ZHAO Xin-bo, HUANG He-ling, LIU Jing

2005, 14(3): 40-45.

Abstract(634) PDF(1)

Abstract:
For ICT image sequence, two kinds of subvoxel surface detection algorithms: facet model-based method and moment-based method are studied. To solve the problem of large computation of both algorithms, a pre-processing procedure based on Otsu threshold segmentation is proposed, which can reduce the number of surface voxel candidates a lot and accelerate the original one greatly. Finally, we compare the two subvoxel edge detection algorithms in the experiment on aeroengine blade simulation data. The results show that both methods can achieve less than 1/5th pixel accuracy and the introduction of the pre-processing procedure can increase the speed about 4 times.

CT Diagnosis of Special Metastasis Tumor

LI Xiao-yang, ZHANG De-jiang, ZHAO Lin, LI Ji, XING Guo-feng, HU Wen-jian

2005, 14(3): 46-50.

Abstract(530) PDF(0)

Abstract:
Objective To analyze the special CT images of metastatis tumor for the purpose of improving CT diagnostic ability. Materials and Methods Thirty-two cases with primary tumor and lung or head or liver or pelvis metastasis tumor by operations and pathology were reviewed. Result The Special CT findings of head metastasis can be devided into two types,tubercular metastasis was found 15 cases, prophyritic metastasis 5 cases; The Special CT findings of liver metastasis show the prophyritic metastasis 1 case; The Special CT findings of pelvis metastasis show the prophyritic metastasis 1 case; The Special CT findings of lung metastasis can be devided into two types,cavernous metastasis was found in 6 cases and vacuolar metastasis was found in 4 cases,prophyritic metastasis 1 cases. Conclusion Consulting to clinical expression and special CT findings,a precise diagnosis could be made in cases of metastasis tumor with special manifestations

A Study on CT X-ray High Frequency and High Voltage Generator

WANG Xiu-bin

2005, 14(3): 51-53.

Abstract(664) PDF(0)

Abstract:
The high frequency and high voltage generator is a most important part of CT. This article mainly introduces the composition and principle of high frequency high voltage generator, The FM and PM methods of the pulse control of high frequency inverter,The choice of the material of magnetic core of the high frequency, The design of coil and the calculation of loss, The consideration of electromagnetic compatibility, The design of the high voltage rectify circuit. To understand the high voltage generator of manufacture 20kHz and 50kHz.

Analysis and Diagnosis of Images for Pneumomycosis Diseases (Attached 34 Reports)

ZHANG Li-bo, LI Peng

2005, 14(3): 54-57.

Abstract(506) PDF(1)

Abstract:
Purpose: Analysis of the CT, X-ray film image characters for pneumonomycosis diseases; evaluate the value of the lung’s mould fungus disease in the imaging area. Method: These images got with HiSpeed NX/I type CT scanner by GE company and adopting the X-ray film 1250 type images by Japanese Shimadzu company, that carrying on looking back analysis research for 34-cases with pneumomycosis patient. Result: There are 19 cases infected with candida albicans, 10 examples are the spores germ fungi balls, all was developed by phlegm and the bacteriology authenticate check, 5 cases was confirmed by surgical operation and pathologic check, for the new latent ball bacteria(germ). Conclusion: These diseases are less appearance in lung area, through the analysis of the CT, X-ray film image characters, combine with laboratory bacteria check, doctors can do an explicit diagnosis to the pneumomycosis disease, we find a new way to get certain experience to diagnose these diseases, guiding the clinic medicine, has the meaning can't be underrated.

The Application of MSCT Angiography 3D Imaging in Cerebrovascular Diseases

HUO Jian-wei, JIN Wen-yi, YIN Xiao-ming, WU Ge, DENG Gang, WANG Jun, CHANG Xin

2005, 14(3): 58-60.

Abstract(487) PDF(0)

Abstract:
Purpose: To evaluate the MSCT angiography 3D imaging in the diagnosis of cerebrovascular diseases. Methods: 20 patients with cerebrovascular disease were studied with CT angiography, using 3D reconstruction of cerebral vessels by post-processing working station to display anatomy of the disease. Results: Within 20 patients, aneurysm 10 cases, AVM 8 cases,cerebral vessels narrowing 2 cases(confirmed by DSA and operation). One aneurysm was confirmed by operation,not detected by DSA. Conclusion: CT angiography 3D reconstruction can omnidirectionally show cerebral vessels, it is a microtraumatic,safe and reliable methods and need less money,suitable for pre-operation planning, localization and follow up.

CT Angiography of Lower Extremities and Aortoiliac System Evaluation by Multi-detector row helical CT

LI Da-sheng, SUN Yong-guang

2005, 14(3): 61-64.

Abstract(513) PDF(1)

Abstract:
CT angiography has been applied in clinic more and more, it’s effect was foucs by a lot of researcher, this article summarizes the newest diagnosis advances of Multi-detector row helical CT angiography in lower extremities and aortoiliac system.

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2005 Vol. 14, No. 3