• Journal of electromagnetic engineering and science
• /
• v.10 no.4
• /
• pp.199-205
• /
• 2010

This paper presents a tumor detection system for breast cancer that utilizes two-dimensional (2D) image reconstruction with microwave tomographic imaging. The breast cancer detection system under development consists of 16 transmit/receive antennas, and the microwave tomography system operates at 900 MHz. To solve a 2D inverse scattering problem, the method of moments (MoM) is employed for forward problem solving, and the simplex method employed as an optimization algorithm. The results of the reconstructed image show that the method accurately shows the position of a breast tumor.

• Journal of electromagnetic engineering and science
• /
• v.14 no.4
• /
• pp.332-335
• /
• 2014

This paper investigates the phase singularity problem in microwave image reconstruction utilizing unwrapped phase data. The measured phases of the electric fields in most microwave measurement systems are wrapped. Thus, a certain phase unwrapping process is necessary for reconstruction of the image of a high contrast object. This unwrapping, however, is difficult in the presence of scattering nulls on/near the unwrapping path. At the null point, the phase value will be rendered, resulting in a poor image reconstruction. In this paper, we investigate the phase singularity arising from electromagnetic scattering nulls in microwave breast tomographic imaging. We then propose a transformation technique for the measured electric fields that avoids phase singularity.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.18 no.2
• /
• pp.54-63
• /
• 1981

An ultrasonic imaging system with fan reflection mode time of fight is developed and its performance has been examined by system implementation. Experimental results obtained indicafe potential of the method for tomographic imaging. The basic concept of this method is reconstruction of reflectivity with reflection data collected in fan mode using a new "arbitrary ray" reconstruction algorithm. Computer simulations as well as experimental results are presented.presented.

• Proceedings of the KIEE Conference
• /
• 1979.08a
• /
• pp.164-165
• /
• 1979

Two dimensional kernels which reconstruct the tomographic image from the blurred one formed by simple back-projection are investigated and their performances are compared. These kernels are derived from tile point spread function of the tomographic system and have the form of a ramp filter modified by several window functions to suppress ringing in the reconstruction. Computer simulation using a computer generated phantom image data with different correction functions(kernels) has been carried out. In this simulation, filtering in frequency domain by 2-D FFT technique or in space domain by 2-D direct convolution is considered. It is found that the-computation time required for real space convolution technique is much larger than that of Fourier 2-D filtering technique in the pratical situation.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.5 no.2 s.17
• /
• pp.1-8
• /
• 2005

Microwave tomographic imaging technology using a bi-focusing operator has been developed in order to detect the internal voids/objects inside concrete structures. The imaging system consists of several cylindrical or planar array antennas for transmitting and receiving signals, and a numerical focusing operator is applied to the external signals both in transmitting and in receiving fields. In this study, the authors developed 3-dimensional (3D) electromagnetic (EM) imaging technology to detect such damage and to identify exact location of steel rebars or dowel. The authors have developed sub-surface two-dimensional (2D) imaging technique using tomographic antenna array in previous works. In this study, extending the earlier analytical and experimental works on 2D image reconstruction, a 3D microwave imaging system using tomographic antenna way was developed, and multi-frequency technique was applied to improve quality of the reconstructed image and to reduce background noises. Numerical simulation demonstrated that a sub-surface image can be successfully reconstructed by using the proposed tomographic imaging technology. For the experimental verification, a prototype antenna array was fabricated and tested on a concrete specimen.

• Archives of Plastic Surgery
• /
• v.43 no.1
• /
• pp.84-87
• /
• 2016

Titanium micro-mesh implants are widely used in orbital wall reconstructions because they have several advantageous characteristics. However, the rough and irregular marginal spurs of the cut edges of the titanium mesh sheet impede the efficacious and minimally traumatic insertion of the implant, because these spurs may catch or hook the orbital soft tissue, skin, or conjunctiva during the insertion procedure. In order to prevent this problem, we developed an easy method of inserting a titanium micro-mesh, in which it is wrapped with the aseptic transparent plastic film that is used to pack surgical instruments or is attached to one side of the inner suture package. Fifty-four patients underwent orbital wall reconstruction using a transconjunctival or transcutaneous approach. The wrapped implant was easily inserted without catching or injuring the orbital soft tissue, skin, or conjunctiva. In most cases, the implant was inserted in one attempt. Postoperative computed tomographic scans showed excellent placement of the titanium micro-mesh and adequate anatomic reconstruction of the orbital walls. This wrapping insertion method may be useful for making the insertion of titanium micro-mesh implants in the reconstruction of orbital wall fractures easier and less traumatic.

• Archives of Reconstructive Microsurgery
• /
• v.20 no.1
• /
• pp.14-17
• /
• 2011

Autologous breast reconstruction after mastectomy in breast cancer patient is now increasing. The deep inferior epigastric artery (DIEA) free flap is well known as an ideal donor site for the microsurgical breast reconstruction. The branching pattern of the DIEA was well described in the literature. In that study, DIEA has three branching patterns near the arcuate line. We describe a case in which branching variation of the DIEA before entering the posterior surface of the rectus abdominis muscle. In three cases, DIEA originated from the external iliac artery ascended as a double trunk at 1cm, 2cm, and 4cm above the originating point, respectively. In one case, DIEA ascended as a single trunk along the linea alba toward to the umbilicus until it supply overlying subcutaneous tissue. Preoperative 3D computed tomographic angiography to identify the anomaly is recommended and meticulous dissection to the originating point of DIEA is needed.

• Journal of Biomedical Engineering Research
• /
• v.12 no.1
• /
• pp.43-48
• /
• 1991

As the computerized methods and equipments In nuclear medicine imaging increases, quantitative information is needed on the single photon emission computed tomographic Images as well as on the conventional nuclear medicine images. In this paper, the authors investigated the effect of several clinician - friendly reconstrution filters on the resultant transverse slices of backprojected Profiles of radioisotope distribution from the Quantitative point of view, and reduced the filter parameters such as cutoff frequency and order of filter which are neces mary to minimize the quantification error using computer-generated phantoms.

• Journal of radiological science and technology
• /
• v.35 no.4
• /
• pp.353-360
• /
• 2012

Diverse designs of collimator have been applied to Single Photon Emission Computed Tomography (SPECT) according to the purpose of acquisition; thus, it is necessary to reflect geometric characteristic of each collimator for successive image reconstruction. This study carry out reconstruction algorithm for imaging system in nuclear medicine with pinhole collimator. Especially, we study to solve sampling problem which caused in the system model of pinhole collimator. System model for a maximum likelihood expectation maximization (MLEM) was developed based on the geometry of the collimator. The projector and back-projector were separately implemented based on the ray-driven and voxel-driven methods, respectively, to overcome sparse sampling problem. We perform phantom study for pinhole collimator by using geant4 application for tomographic emission(GATE) simulation tool. The reconstructed images show promising results. Designed iterative reconstruction algorithm with unmatched system model effective to remove sampling problem artefact. Proposed algorithm can be used not only for pinhole collimator but also for various collimator system of imaging system in nuclear medicine.

• Journal of Chest Surgery
• /
• v.51 no.3
• /
• pp.202-204
• /
• 2018

We report a case of high-output chylothorax associated with thrombo-occlusion of the superior vena cava (SVC) and left innominate vein (LIV) following an arterial switch operation in a neonate. The chylothorax was resolved by 3 weeks after surgical reconstruction of the SVC and LIV using fresh autologous pericardium. We confirmed the patency of the SVC and LIV with a 1-year follow-up computed tomographic scan at our outpatient clinic.