• Smart Structures and Systems
• /
• v.3 no.4
• /
• pp.439-454
• /
• 2007

In this paper a damage imaging technique using pre-stack migration is developed using Lamb (guided) wave propagation in composite structures for imaging multi damages by both numerical simulations and experimental studies. In particular, the paper focuses on the experimental study using a finite number of sensors for future practical applications. A composite laminate with a surface-mounted linear piezoelectric ceramic (PZT) disk array is illustrated as an example. Two types of damages, one straight-crack damage and two simulated circular-shaped delamination damage, have been studied. First, Mindlin plate theory is used to model Lamb waves propagating in laminates. The group velocities of flexural waves in the composite laminate are also derived from dispersion relations and validated by experiments. Then the pre-stack migration technique is performed by using a two-dimensional explicit finite difference algorithm to back-propagate the scattered energy to the damages and damages are imaged together with the excitation-time imaging conditions. Stacking these images together deduces the resulting image of damages. Both simulations and experimental results show that the pre-stack migration method is a promising method for damage identification in composite structures.

• Korean Journal of Digital Imaging in Medicine
• /
• v.11 no.2
• /
• pp.59-62
• /
• 2009

The purpose of this study is to know about solution of insecurity sense for solving the tediousness and inducing comfortableness in long time MRI examination. Studies were examined with total of 117 patients that the intention expression of self is possible for a month without dividing man and woman in november 2006. Examination methods were filled in questionnaire after testing using Siemens Impact 1.0T. The musical art were selected through intranet search and record sale inquiry using CD player and speaker. That kind of a music were selected with Korean classical music's 10 chapter, pop song 10's chapter, classic's 10 chapter and Korean popular song's 10 chapter. With analytical method, patients of under 40 year-old, or older and patients using ear-pad and head-phone were classified into groups. As analysis result with question item of questionnaire, most of the patients were showed a favor(36.72%) in playing a music, specially, examination of about 15.38% which uses the headphone prefer a music as older generation of over 40 year-old. In conclusion, with installing of the professional musical program in MRI test rooms, if listening to the music with selection by oneself before testing by season, age, time through development of appropriate musical program will be able to expect the more effect.

• Korean Journal of Digital Imaging in Medicine
• /
• v.10 no.2
• /
• pp.39-49
• /
• 2008

Extravasation of contrast material is a not infrequent complication of enhanced imaging studies and large volume extravasation may result in severe damage. Subcutaneous extravasation of the radiographic contrast medium is one of the complications of the contrast medium-enhanced procedures. Automated power injectors enable the contrast material to be delivered at a uniform high-flow-rate and as a nonfragmented bolus, and this is essential for many contrast material enhanced CT(computed tomography) applications. The major risk associated with the use of automated power injectors is the well known complication of contrast material extravasation at the injection site. Automated injection of CT contrast material can produce the compartment syndrome. Selection of the nonionic contrast material after careful evaluation of the intravenous administration site and monitoring of the patient during the use of a mechanical power injector may help minimize or prevent extravasation injuries. Early identification is important and conservative management is effective in most cases. Prevention of these injuries with the education of radiological technologist remains the ultimate aim.

• Korean Journal of Veterinary Service
• /
• v.34 no.1
• /
• pp.1-4
• /
• 2011

A surface plasmon resonance imaging (SPRI) assay was developed for measuring porcine circovirus type 2 (PCV2) antibody using a recombinant capsid protein as an antigen. The diagnostic potential of SPRI for detecting antibodies to the PCV2 capsid protein was compared with that of a conventional enzyme-linked immunosorbent assay (ELISA) using 70 pig serum samples taken from 6 pig farms. There was a strong positive correlation between the SPRI and ELISA (n = 70, r = 0.911, P<0.01). Therefore, this recombinant capsid protein can be used as an antigen for serological studies, and the SPRI, a label-free and high-throughput method, is expected to be a valuable tool in the serodiagnosis of PCV2 infection.

• Molecules and Cells
• /
• v.23 no.2
• /
• pp.132-137
• /
• 2007

With the advance of stem cell transplantation research, in vivo cell tracking techniques have become increasingly important in recent years. Magnetic resonance imaging (MRI) may provide a unique tool for non-invasive tracking of transplanted cells. Since the initial findings on the stem cell migration by MRI several years ago, there have been numerous studies using various animal models, notably in heart or brain disease models. In order to develop more reliable and clinically applicable methodologies, multiple aspects should be taken into consideration. In this review, we will summarize the current status and future perspectives of in vivo cell tracking technologies using MRI. In particular, use of different MR contrast agents and their detection methods using MRI will be described in much detail. In addition, various cell labeling methods to increase the sensitivity of signals will be extensively discussed. We will also review several key experiments, in which MRI techniques were utilized to detect the presence and/or migration of transplanted stem cells in various animal models. Finally, we will discuss the current problems and future directions of cell tracking methods using MRI.

• Korean Journal of Digital Imaging in Medicine
• /
• v.15 no.1
• /
• pp.55-59
• /
• 2013

Patients who had claustrophobia tend to feel fear when they were scanned by an MRI, CT, PET-CT, or using a gamma camera scan. In this paper, claustrophobic patients were tested to find effective ways by changing patient's positions. For this paper, PET-CT scan in patients who had claustrophobia were used in the prone position. Prone position helped to maintain stable position and to get a h0igh quality of inspection without failure. Thus, as claustrophobic patients were requested taking prone position, they could feel comfortable. In a confined space, prone position for the claustrophobic patients who had a fear of the PET-CT examination would be expected to reduce the failure rate of inspection.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.05a
• /
• pp.773-774
• /
• 2016

In this study, we perform the weight reduction and miniaturization of the shielding element that is applied for gamma-ray detectors for imaging of gamma-ray source. Through previous studies, we implemented a lead-based shielding element that represents the shielding effectiveness and performance of commercially available gamma-ray imaging apparatus similar to the shielding body. In this paper, we designed a tungsten-based shield for weight reduction and miniaturization than lead-based shield. We performed the MCNP simulation for shield design and then we obtained the results of reducing the weight of the 17% and 51% of the volume.

• Earthquakes and Structures
• /
• v.8 no.4
• /
• pp.821-841
• /
• 2015

This paper proposes a two-stage imaging approach for quantitative inspection of damages in metallic plates using the fundamental anti-symmetric mode of ($A_0$) Lamb wave. The proposed approach employs a number of transducers to transmit and receive $A_0$ Lamb wave pulses, and hence, to sequentially scan the plate structures before and after the presence of damage. The approach is applied to image the corrosion damages, which are simplified as a reduction of plate thickness in this study. In stage-one of the proposed approach a damage location image is reconstructed by analyzing the cross-correlation of the wavelet coefficient calculated from the excitation pulse and scattered wave signals for each transducer pairs to determine the damage location. In stage-two the Lamb wave diffraction tomography is then used to reconstruct a thickness reduction image for evaluating the size and depth of the damage. Finite element simulations are carried out to provide a comprehensive verification of the proposed imaging approach. A number of numerical case studies considering a circular transducer network with eight transducers are used to identify the damages with different locations, sizes and thicknesses. The results show that the proposed methodology is able to accurately identify the damage locations with inaccuracy of the order of few millimeters of a circular inspection area of $100mm^2$ and provide a reasonable estimation of the size and depth of the damages.

• Korean Journal of Bronchoesophagology
• /
• v.14 no.2
• /
• pp.70-72
• /
• 2008

Nerogenic tumor of various histologic types may arise in the posterior mediastinum. Mediastinal schwannoma is a frequent paraspinal neurogenic tumor, but malignant mediastinal schwannoma is rare tumor which is derived from Schwann cells. Although there are some reports dealing with approach for screening patients with symptoms suggesting malignancy and the imaging criteria for distinguishing malignant from benign schwannoma but the results are not clearly defined. We present a case of hugh mediastinal schwannoma which was taken for malignancy in imaging studies because of its invasiveness.

• 한국가시화정보학회:학술대회논문집
• /
• 2006.12a
• /
• pp.92-95
• /
• 2006

The global environment is deteriorating at an alarming rate despite of enhanced international environmental regulation. Many studies have been performed to reduce pollutants. Recently, phytoremediation, plant-based technology for the removal of toxic contaminants from soil, water, and air, has been receiving large attention. Arsenic-contaminated soil is one of the major pollutant sources fur drinking water. The fern brake (Pteris erotica) has been reported as a hyper-accumulate arsenic from soils. In this study, we investigated the arsenic absorption effect on sap flow inside xylem vessels of a fern brake. The synchrotron X-ray micro-imaging technique was employed to monitor flow inside the plant non-invasively. The captured phase-contrast X-ray images show both anatomy and transport of water inside the fern brake. The refilling process of water containing arsenic inside the xylem vessels of fern brake's leaves and stems was clearly observed. These results would provide important information needed fur understanding the mechanisms of accumulation, translocation, and transformation of toxic materials in plants.