CT理论与应用研究

Improveing S/N Ratio of MRS Signal of Detecting Ground Water with Wavelet Analysis

CENG Liang, LI Zhen-yu, WANG Peng

2006, 15(2): 1-5.

Abstract(839) PDF(0)

Abstract:
Nuclear magnetic resonance (NMR) technique is the only one geophysical new method of directly detecting underground water so far. Because the high sensitivity of this method, it is very sensitive to electromagnetic noise also. In order to improve the ratio of signal to noise (S/N ratio) and this new method’s effect of detecting water, we should eliminate the noise contained in the received signal. This paper introduces a way to improve S/N ratio of the NMRS by wavelet analysis and analyzes the processed results from the cases in Xin Zhou and Wang jiawan investigation areas, finally,demonstrates the availability to use this method in practice.

Application and Effect of Combination of SNMR and TEM in Detecting Groundwater

CHENG Miao, LI Zhen-yu, WANG Peng

2006, 15(2): 6-12.

Abstract(697) PDF(0)

Abstract:
SNMR, developed in recent 20 years, is a physical method of groundwater detecting. Being of new principle and able to achieve quantified results, it has been greatly useful. TEM is a branch of electro-magnetic method which has been developed fast in recent years. Theoretical research and field work indicates that, to make use of both advantages of the two methods, it is the combination of the them that performs better. The principle and feature of both SNMR and TEM methods were introduced in this paper, as well as the possibility of the combination of them. Examples are given to demonstrate the effectiveness of the above mentioned work mode.

A Calibration Method for the Misaligned Geometry of Hard X-ray Diffraction Enhanced Top Position Imaging CT

SUN Yi, ZHU Pei-ping, LIU Ming-he, YU Jian

2006, 15(2): 13-21.

Abstract(723) PDF(1)

Abstract:
Recently the technique of phase contrast imaging has become an useful and special tool in biology, material science etc. due to its high resolution. In this paper, we reconstruct the fly in a capsule, calibrate the misaligned geometry by sample information itself. The quality of the CT images is greatly improved and the efficiency of the calibration method is proved.

Siemens Multi-Slice CT New Technologies

XU Xiao-dong, SHAO Jun-ming, KONG Jun

2006, 15(2): 22-27.

Abstract(1174) PDF(0)

Abstract:
With rolling out the multi-slice spiral CT, the ability of CT application is strongly enhanced, and CT scanner comes into the period of fast developing. In this paper, the representative Siemens CT new technologies, including Z-Sharp, SureView, spiral reconstruction algorithms and CARE Dose 4D and so on are introduced, which show the efforts of Siemens in CT innovation. The great success of Siemens 64 in the market has demonstrated its excellence.

Introduction of Clinical PET Technology

CENG Hai-ning, LIU Xiao-ping, ZHAO Ming

2006, 15(2): 28-32.

Abstract(646) PDF(0)

Abstract:
PET(Positron Emission Tomography)is the most advanced technology now in nuclear medicine, it integrates many up-to-date technologies in nuclear science, electronics, computer, data processing, etc., PET set is also the most important imaging diagnosis devise in clinical medicine, which now plays more and more important role in the diagnosis of human cancer, myocardial and brain disease. Using the homemade 32-Ring PET as an example, the general working principle, the functional structure are overviewed in this article, and its clinical application is demonstrated as well.

Research on Medical Image Based on VTK

LIU Zhi-jian, WANG Rong, LIU Yu-ling, YU Fei-hong

2006, 15(2): 38-42.

Abstract(701) PDF(0)

Abstract:
The visualization of medical 3-D data is a main application of Scientific Visualization. The properties of the Visualization Toolkit(VTK) are introduced in this paper. The principle and method of 3-D medical visualization system development based on the VTK are given. With a series of section images, the 3-D medical images are reconstructed successfully based on the VTK. Also the 2-D images can be browsed one by one and their statistic histogram is realized. The experimental results shows that VTK is easy to use and has powerful functions and is an effective visualization tool for medical 3-D data.

Practice and Study on Automatic Measurement of CT Spatial Resolution

ZHAN Jie, YU Xiao-e

2006, 15(2): 43-46.

Abstract(706) PDF(2)

Abstract:
Objective To measure spatial resolution with MTF method. Method The Catphan phantom and self-prepared experimental phantom were used to measure spatial resolution based on the analyzing of measurement principle. Result the results of subject method was basically consistent with that of the object method. Conclusion it is feasible to do the automatic measurement for CT using self-prepared experimental phantom.

Review of Image Registration Methods for Medical Images

WANG Cai-fang, JIANG Ming

2006, 15(2): 74-80.

Abstract(661) PDF(3)

Abstract:
Purpose: Review different methods in medical image registration.Method: Parametric and non-parametric registration methods. Result: Various registration methods and applications are presented. Conclusion: Different registration methods fit to different kinds of medical images and result different applications in medical field. In medical field, researchers need to combine and compare the information given by functional and anatomical images. For the reason, image registration which can map points from one image to homologous points on an object in the second image is one of the fundamental tasks in image processing. Different numerical methods are introduced into registration due to the different images taken from different perspectives, times and devices. In this paper, we present an overview of recent methods for image registration in medical field. We start by the goal of image registration and introduce the framework of a registration process. The registration methods under review are classified into two categories: parametric image registration and non-parametric image registration. Typical methods in each category are presented. In each case, we provide the readers with general background information and properties or explanation of how these methods work.

On Microcalcifications Detection in Mammograms Based on Morphological Grayscale Reconstruction

WEN Hao, MA Jin-sheng, WANG Yu-hui, ZHUANG Da-min

2006, 15(2): 33-37.

Abstract(780) PDF(1)

Abstract:
A novel approach to computer aided microcalcifications detection in mammograms was presented. Firstly dome extraction was accomplished by using morphological grayscale reconstruction, which could not only remove the breast structures but also remain microcalcifications commendably. Secondly microcalcifications were enhanced by utilizing Laplacian operator in spatial domain. Thirdly Butterworth highpass filters was adopted to located microcalcifications incipiently. Lastly two-dimensional entropic thresholding was applied to segmentation image, thus microcalcifications were detected and were marked in mammograms. The proposed method could avoid misdiagnosis because of doctors’ fatigue causing by reading large amount of films. It played an important role of assisting doctors to diagnose and it also improved the efficiency and accuracy of diagnosis.

CT Observing Thickness of Stomach at Background of Malignancy Tumor

YANG Jun-quan, LI Xiao-yang, MA Ju-wen, ZHONG Hong-bo, HU Wen-jian

2006, 15(2): 47-51.

Abstract(702) PDF(0)

Abstract:
objective: Discuss the connection at the thick of stomach with the background of malignant tumor. Methods 140 patients of the malignancy in the body except the stomach were studied, abdomen were all examed by CT scaning, female 59 cases, male 81 cases,110 cases were cureing by the treatment of chemistry. The original tumor was pulmonary cancer,liver cancer,colon cancer,galactophore cancer,vein sarcoma,small intestine (gastrointestinal), cervical cancer,et.al. Fasting in the morning, all taking eau douce 300ml~500ml before CT scaning. Conclusion study and analyzed 140 cases’thick of stomach with the background of chemistry, we finded the thickness of stomach is just relationship with the background of chemistry and the cureing by the treatment of chemistry.

Study in Diagnosis of Small Hepatocellular Carcinoma using Ultrasound and 16 Multislice scan

DAI Lin, XU Yi-kai, FENG Xiao-rong

2006, 15(2): 52-55.

Abstract(619) PDF(0)

Abstract:
Objective To evaluate the value of clinical application of ultrasound and 16 multislice scan in diagnosis of small hepatocellular carcinoma(SHCC). Methods 18 patients with SHCC and 17 patients with benign tumors of liver detected respectively by ultrasound and the high-quality scan mode of 16 multislice scan were compared and analyzed. All cases were confirmed by pathological examinations after the operation and puncturatio. Results: Major cases of SHCC and benign tumors of liver had the typical sonogram features by ultrasonic. Among them, 14 cases of SHCC and 15 cases of benign tumors of liver were diagnosed in coincidence with 16 multislice scan and pathological examinations. However, 3 cases of SHCC had misdiagnosed as 1 case of vascular tumor and 3 cases of hyperlasa noduses, and 3 cases of benign tumors were misdiagnosed as SHCC , 2 cases of constrictive noduses confirmed by CT and pathological examination, but 1 case of inflammatory pseutotumour of liver(IPL) was misdiagnosed also by 16 multislice scan. Conclusion Ultrasonic was the first choice for the routine examination. It had a higher detection rate for benign and malignant tumors of liver. But for some non-typical cases, it still needed further examination using 16 multislice scan and pathological test to enhance the early diagnostic rate.

Research of 16-slice Spiral CT Angiography in Diagnosis of Carotid Body Tumor and Choice of Modus Operandi

LIU Ying, SUN Jian-nan, ZHANG Xiu-li, ME Gang

2006, 15(2): 56-59.

Abstract(678) PDF(0)

Abstract:
Object To study the value 16-slice Spiral CT angiography in the diagnosis of Carotid-body tumor and choice of modus operandi. Material and methods 12 patients with Carotid body tumor were examined with CTA,all performed Volume Rendering(VR)、Maximum Intensity Projection(MIP)、 Multiplanar(MPR)。 Results Situating at the bifurcation of the common carotid artery,the tumors presented is-or high-density mass with defined margin and marked enhancement in CT. Conclusion 16-slice Spiral CT is of great value in the diagnosis of Carotid body tumor and choice of modus operandi.

Diagnostic Application of CT-A for Evaluation of Neck Vessels Diseases

LI Zhong-kai, LI Li, ZHANG Li-bo, WANG Su

2006, 15(2): 60-63.

Abstract(857) PDF(0)

Abstract:
Objective To evaluate CT-A in diagnosing neck vessels^s disease. Methodes: 20 clinical high suspicion of stenosis of neck vessels were examined with CT angiography.Among them,6 cases were clinical suspicion of ischemia of carotid artery,14 cases shown ischemia of vertebral basal system.Using GE(High-speed NX/I) 2 Row spiral CT. analysis with reconstruction techniques(MIP,SSD,MPR & Curve and CTVE). Results: Among the 20 patients, 4 with stenosis of carotid artery and calcified plaque,mainly in the original part and the calcified plaque mainly located at the bifurcation of carotid artery,2 cases with calcified spot in endovascular wall at bifurcation part were noted by CTVE.12 cases with stenosis of vertebral artery; 2 cases shown zigzagging with circuitous,no stenosis by CTVE. Conclusion: CT-A is a fast,easy,safe and non-traumatic technique,it can show the main vessels of neck,with a well foreground of clinical application.

Relation Analysis between Volume Percent of Crack Defect and CT Number

AO Bo, ZHAO Xin-bo, ZHANG Ding-hua, XU Xia-gang, WANG Huan-shu

2006, 15(2): 64-68.

Abstract(674) PDF(2)

Abstract:
In this paper, from the linear representation of linear attenuation coefficient of mixture, density variations and CT number variations are induced by microcracks under stress, the formula between relative density variations and relative CT number variations is obtained without impurity. With further analyzing, a formula between relative volume percent of crack defect variations and relative CT number variations is obtained respectively, without impurity and with impurity, and we extend conclusion of impurity to impurities. All these lay a theoretical foundation for material fatigue life prediction by using CT.

Adjusting of Cone-beam X-ray Source of Micro CT

FANG Quan, FANG Zheng, ZHONG Ai-jun, LUO Qing-ming, GONG Hui

2006, 15(2): 69-73.

Abstract(540) PDF(2)

Abstract:
Accurate coordinate of X-ray source is one of the key parameters in design of micro CT based on cone-beam X-ray system. The method of calculating the coordinate of X-ray source through a metallic ball model's 2-D projections is represented. It is based on micro source system which the source is counted as a particle under a certain amplification. Coordinate of the source could be calculated through projective lines. Avoiding the micro CT system is fixed, cone-beam reconstruction formulas with a nonstationary shift of X-ray source are represented. Model test are performed to show the effect after corrected for the shift of X-ray source.

NoticeMore>

linksMore>

2006 Vol. 15, No. 2