• Journal of the Korean Fracture Society
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• v.30 no.4
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• pp.186-191
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• 2017

Purpose: The purpose of this study was to investigate the radiological and epidemiological characteristics, as well as the clinical course of pelvic insufficiency fractures in the elderly population. Materials and Methods: At a Haeundae Paik Hospital, we retrospectively reviewed patients with pelvic insufficiency fractures between March 2010 and May 2017. The demographic data of patients were analyzed, and bone mineral density and bone turnover markers were evaluated to estimate the metabolic status of the bone. The radiological characteristics were evaluated by comparing the simple x-ray images with the computed tomography images, and the types of fractures were classified via computed tomography images. For clinical course evaluation, we investigated comorbid complications, and compared the walking ability scale before and 6 months after the fracture. Results: A total of 42 patients were included, with an average age of 76.5 years. All were female except one case. In 5 cases where the initial medical examination was from another institution, the fracture was not found in 3 cases. All cases received conservative treatment. After the diagnosis of pelvic bone fracture using a simple x-ray imaging, additional fractures were found in 81.0% of the study population using a computed tomography. Initiation of gait occurred at an average of 2.8 weeks, and every case except 1 (97.6%) fully recovered their gait ability. Conclusion: We concluded that there was a limitation with diagnosing pelvic insufficiency fracture using only a simple x-ray imaging technique. In general, cases in this study showed conservative treatment yielded favorable clinical outcome with relatively less critical complications.

• Journal of Biomedical Engineering Research
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• v.32 no.3
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• pp.257-263
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• 2011

Sparse-view CT imaging is considered to be a solution to reduce x-ray dose of CT. Sparse-view CT imaging may have severe streak artifacts that could compromise the image qualities. We have compared quality of sparseview images reconstructed with two representative iterative reconstruction techniques, SIRT and TV-minimization, in terms of image error and edge preservation. In the comparison study, we have used the Shepp-Logan phantom image and real CT images obtained with a micro-CT. In both phantom image and real CT image tests, TV-minimization technique shows the best performance in error reduction and preserving edges. However, the excessive computation time of TV-minimization is a technical challenge for the practical use.

• Clinics in Shoulder and Elbow
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• v.20 no.4
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• pp.244-249
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• 2017

Shoulder kinematics is important, as it is associated with shoulder arthropathy and pain mechanisms. Various static and dynamic analysis methods are prevalent for shoulder kinematics. These include 2-dimensional plane x-ray, computed tomography, and magnetic resonance imaging, cadaver study, electromagnetic motion analysis, transcortical bone pins technique, and in vivo 3-dimensional motion analysis. Although these methods provide the value of the shoulder kinematics angle, they are unable to explain why such changes occur. Since each method has its pros and cons, it is important to understand all factors accurately, and to choose a method that best meets the purpose of the researcher.

• Journal of Power System Engineering
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• v.15 no.4
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• pp.25-30
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• 2011

This study is made to provide with a method for correcting the geometric distortion of the digital radiography image by analytical approach based upon the inverse square law and Beer's law. This study is aimed to find out and improve a mathematic model of nonlinear type. Variations in the alignment of the X-ray source, the object, and imaging plate affect digital radiography images. A model which is expressed in parameter values; e.g, angle, position, absorption coefficient, length, width and pixel account of radiography source, is developed so as to match the sample image. For the best correction of the digital image that is the most similar to the model image, a correction technique based upon tangent is developed; then applied to the digital radiography images of steel tubes. As a result, the image correction is confirmed to be made successfully.

• The Korean Journal of Pain
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• v.23 no.3
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• pp.202-206
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• 2010

Magnetic resonance image (MRI) is the most sensitive imaging test of the spine in routine clinical practice. Unlike conventional x-ray examinations and computed tomography scans, high-quality magnetic resonance images can be assured only if patients are able to remain perfectly still. However, some patients find it uncomfortable to remain still because of pain. In that condition, interlaminar cervical epidural injections can reduce pain and allow the procedure. When using air with the "loss of resistance" technique in epidural injections to identify the epidural space, there is the possibility of injected excessive air epidurally to mimic a herniated disc. We describe a case report of epidural air artifact in a cervical MRI after cervical epidural injections.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.297-298
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• 1998

Prototype portal imaging device (EPID) based on CCD camera, which has a $20\times20cm^2$ field of view (FOV), has been developed and then tested by acquiring phantom images for 6 MV x-ray beam. While, among the captured images, each frame suffered notorious quantum noise, the frame averaging largely enhanced the image quality against quantum noise. Over 60 frames averaging, the signal-to-noise ratio (SNR) was increased by $\sim20$ times and contrast was increased about 2 times in the skull-region of the acquired head-phantom image.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.362-363
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• 2007

The transport property of stabilized amorphous selenium typical of the material used in direct conversion x-ray imaging devices was studied using the moving photo-carrier grating (MPG) technique and time-of-flight (TOF) measurements. For MPG measurement, the electron and hole mobility, and recombination lifetime of a-Se films with arsenic (As) additions have been obtained. For TOF measurement, a laser beam with pulse duration of 5ns and wavelength of 350 nm was illuminated on the surface of a-Se with thickness of $400{\mu}m$.

• Journal of the Korean Society of Radiology
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• v.81 no.2
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• pp.290-301
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• 2020

The surgical technique of mitral valvuloplasty or transcatheter mitral valve (MV) replacement has been developed recently. Surgeons and interventionists require detailed anatomical information on the MV for the purpose of treatment planning. In this review, we discussed the anatomic features of the MV on CT and the method of evaluating the MV for treatment planning, as well as its preservation, for interventional procedures.

• Journal of Internet Computing and Services
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• v.17 no.1
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• pp.101-107
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• 2016

Due to the recent advancement in digital imaging technology, development of intervention equipment has become generalize. Video arbitration procedure is a process to insert a tiny catheter and a guide wire in the body, so in order to enhance the effectiveness and safety of this treatment, the high-quality of x-ray of image should be used. However, the increasing of radiation has become the problem. Therefore, the studies to improve the performance of x-ray detectors are being actively processed. Moreover, this intervention is based on the reference of the angiographic imaging and 3D medical image processing. In this paper, we propose a guidance system to support this intervention. Through this intervention, it can solve the problem of the existing 2D medical images based vessel that has a formation of cerebrovascular disease, and guide the real-time tracking and optimal route to the target lesion by intervention catheter and guide wire tool. As a result, the system was completely composed for medical image acquisition unit and image processing unit as well as a display device. The experimental environment, guide services which are provided by the proposed system Brain Phantom (complete intracranial model with aneurysms, ref H+N-S-A-010) was taken with x-ray and testing. To generate a reference image based on the Laplacian algorithm for the image processing which derived from the cerebral blood vessel model was applied to DICOM by Volume ray casting technique. $A^*$ algorithm was used to provide the catheter with a guide wire tracking path. Finally, the result does show the location of the catheter and guide wire providing in the proposed system especially, it is expected to provide a useful guide for future intervention service.

• The Korean Journal of Nuclear Medicine
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• v.19 no.1
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• pp.73-75
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• 1985

Acute transient synovitis of the hip presents clinically pain and limping. But in the majority of the cases, definite positive findings are not manifest in roentgenogram in its early phase. However radionuclide bone imaging combines with the assessment of vascularization and bone tracer uptake is of great value in solving this diagnostic problem. The materials for this study consisted of 29 children with acute transient synovitis of the hip, characterized by symptoms and physical signs of an arthritis, negative X-ray findings and disappearance of all symptoms and signs within a short period of time. They were twenty males and 9 females and age ranged from 1 to 12 years. We took pelvic reontgenogram in AP and frog-leg views. After intravenous bolus injection of 10 to 15 mCi of $^{99m}Tc-methylene$ diphosphonate, 24 sequential image of the pelvis was taken at 2-second interval for blood flow study. The scintigrams were made using a gamma camera with high resolution parallel hole collimator. Blood pool imaging was obtained at 2 minutes after tracer administration. After 3 hours, static images were taken and then closeup image of the hip using pin-hole collimator was followed. The results were as follows: 1) Bone scintigram was much more sensitive than conventional roentgenogram in diagnosis of acute transient synovitis of the hip. 2) Three-phase imagings showed increased vascular activities in blood pool scintigrams in 96%. 3) Pin-hole imaging showed increased tracer uptake in the regional bones of the hip, par ticularly in the medial aspect of femoral head and acetabulum. 4) We confirmed that three-phase imaging reinforced with pin-hole technique were very useful in diagnose of acute transient synovitis of the hip.