• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.4
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• pp.391-397
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• 2011

Conventional film radiographic test has been generally and widely used in the inspection on the weldment for quality assurance. On the other hand, since the analog RT is well known for typical time and cost consuming method with complex process of inspection, the industry has researched various ways how to improve radiographic test technology. In this study, we verified the fact that digital RT provides a lot more benefit in effectively detecting defects, ever film details, through digital processing of image enhancement, compared to film RT. As a result, we reached conclusion that digital RT is positively able to replace the film RT in industry in part or in whole.

• Journal of Applied Reliability
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• v.18 no.3
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• pp.240-249
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• 2018

Purpose: The purpose of this research is to find which technique, between the PAUT (Phased array ultrasonic test) that has been used widely in practice and RT (Radiographic test) that was used widely in the past, has the higher reliability as a non-destructive testing of welding points in water wall tubes. Methods: To evaluated the reliability of non-destructive testing, eleven test pieces that were fabricated intentionally, which have the most frequently occurred defect types in water wall tubes and then both the PAUT and RT were performed on those eleven test pieces to compare their reliability. Results: The differences of type of defect, length are occurred due to the characteristics of nondestructive testing. The RT could not detect the lack of fusion defect type in specimen #4 and #8 while PAUT could not detect the lateral crack and 1 mm size small porosity in specimen #11. Conclusion: It is concluded that applying both the RT and PAUT result the best reliability rather than applying only one test method, if it is possible, in nondestructive testing of weld water wall tube in thermal power plant boiler case.

• Journal of Korean Dental Science
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• v.13 no.1
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• pp.28-34
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• 2020

Purpose: The purpose of this study was to investigate the influence of different implant computer software on the accuracy of image registration between radiographic and optical scan data. Materials and Methods: Cone-beam computed tomography and optical scan data of a partially edentulous jaw were collected and transferred to three different computer softwares: Blue Sky Plan (Blue Sky Bio), Implant Studio (3M Shape), and Geomagic DesignX (3D systems). In each software, the two image sets were aligned using a point-based automatic image registration algorithm. Image matching error was evaluated by measuring the linear discrepancies between the two images at the anterior and posterior area in the direction of the x-, y-, and z-axes. Kruskal-Wallis test and a post hoc Mann-Whitney U-test with Bonferroni correction were used for statistical analyses. The significance level was set at 0.05. Result: Overall discrepancy values ranged from 0.08 to 0.30 ㎛. The image registration accuracy among the software was significantly different in the x- and z-axes (P=0.009 and <0.001, respectively), but not different in the y-axis (P=0.064). Conclusion: The image registration accuracy performed by a point-based automatic image matching could be different depending on the computer software used.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.19 no.1
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• pp.55-64
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• 1989

The purpose of this study was to clarify that scintigram was a more effective method than radiogram in the early detection of periapical lesion. Periapical lesions were produced artificially by the opening of the pulp chambers of the lower right 3rd and 4th premolars in 6 dogs. The serial bone scintigrams using 99m-Tc-MDP and periapical radiograms were taken weekly. The uptake counts of the 99-Tc-MDP in the experimental side were compared with those in the control side. The periapical radiograms were interpreted with the joint evaluation by three dental radiologists. The following results were obtained; 1. The radioactivity in the experimental side was increased at the Ist week except one animal in which the radioactivity was increased at the 2nd week. 2. It was observed that increasing amount of radioactivity per week was prominent from the 1st day of experiment to the Ist week, and the 3rd week to the 4th week. 3. The radiographic evidence of the periapical lesions was observed at the 3rd week and became more apparent at the 4th week. 4. Histologically, proliferation of blood vessels and infiltration of chronic inflammatory cells were observed at the 1st week and osteoblasts were found after the 3rd week.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.105-115
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• 2006

Thickness is a commonly used parameter in product design and manufacture. Its intuitive definition as the smallest dimension of a cross-section or the minimum distance between two opposite surfaces is ambiguous for intricate solids, and there is very little reported work in automatic computation of thickness. We present three generic definitions of thickness: interior thickness of points inside an object, exterior thickness for points on the object surface, and radiographic thickness along a view direction. Methods for computing and displaying the respective thickness values are also presented. The internal thickness distribution is obtained by peeling or successive skin removal, eventually revealing the object skeleton (similar to medial axis transformation). Another method involves radiographic scanning along a viewing direction, with minimum, maximum and total thickness options, displayed on the surface of the object. The algorithms have been implemented using an efficient voxel based representation that can handle up to one billion voxels (1000 per axis), coupled with a near-real time display scheme that uses a look-up table based on voxel neighborhood configurations. Three different types of intricate objects: industrial (press cylinder casting), sculpture (Ganesha idol), and medical (pelvic bone) were used for successfully testing the algorithms. The results are found to be useful for early evaluation of manufacturability and other lifecycle considerations.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.4
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• pp.71-77
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• 2008

This paper presents a methodology for recovering the industrial radiographic images from the effects of nonlinear distortion. Analytical approach based on the inverse square law and Beer's law is developed in order to improve a mathematic model of nonlinear type. The geometric effect due to dimensions of the radioactive source appeals on the digitized images. The relation that expresses parameters values(angle, position, absorption coefficient, length, width and pixel account) is defined in this model, matching with the sample image. To perform the search for image recovery most similar to the model, a correction procedure is designed. The application of this method on the radiographic images of steel tubes is shown and recovered results are discussed.

• Journal of Korean Neurosurgical Society
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• v.51 no.1
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• pp.66-70
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• 2012

Thoracic pedicle screw fixation techniques are still controversial for thoracic deformities because of possible complications including neurologic deficit. Methods to aid the surgeon in appropriate screw placement have included the use of intraoperative fluoroscopy and/or radiography as well as image-guided techniques. We describe our technique for free hand pedicle screw placement in the thoracic spine without any radiographic guidance and present the results of pedicle screw placement analyzed by computed tomographic scan in two human cadavers. This free hand technique of thoracic pedicle screw placement performed in a step-wise, consistent, and compulsive manner is an accurate, reliable, and safe method of insertion to treat a variety of spinal disorders, including spinal deformity.

• Archives of Reconstructive Microsurgery
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• v.17 no.1
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• pp.42-47
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• 2008

Introduction: To evaluate the efficacy of superior gluteal artery-pedicled iliac crest for the treatment of avascular necrosis of femoral head. Material & Method: From January 2001 to October 2001, we used the superior deep branches of superior gluteal artery for the pedicled posterior iliac crest bone graft to revascularize the avascular femoral head in 4 patients. They were 1 man and 3 women, and the mean age of the patients was 34 years (range, 27 to 60). The average follow-up after surgery was over 57 months (range, 15 to 82). We analyzed the clinical results by the Harris hip score, and evaluated the vascularity of the femoral head by radiographic methods. Results: All cases showed no evidence of collapse on femoral heads and good revascularizations on the radiographic images. The average Harris hip score was 88.5 points. There was no complication. Conclusion: The revascularization procedure using the superior gluteal artery-pedicled posterior iliac crest was thought to be one of the effective and promising techniques for the treatment of the avascular necrosis of femoral head.

• Journal of radiological science and technology
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• v.23 no.1
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• pp.55-61
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• 2000

This report was the results of an investigation based on the status of the mammography in the 45 medical facilities in the areas of Seoul and Kyong-Gi Do. In regard to mammography we were able to understand the rectification method of the generator, the functions, the radiographic techniques, the patient exposure dose, etc. Recently, the occurrence of breast cancer has rapidly increased and has lead to increased interest in the early discovery of breast cancer. However, mammography has not kept up with the publics interests and its demand. The main problem is thought to be a wide great difference in the quality of the facilities, especially in the techniques of radiograpic and the capabilities of the generator, which would have a major effect on the grade management of the image quality. In order to be ready and keep up with the high rate of increase of breast cancer, the standardization of mammography and the grade management is urgently required as a solution to the problems in the increase of image qualify and the decrease of dose. It is regarded that the basic guide of the techniques of photography in the mammography, which is being used in all developed countries due to the influence of the USA, should be presented, especially in Korea, and for this, more active and enthusiastic education and enlightenment should be needed.

• The Korean Journal of Nuclear Medicine
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• v.37 no.3
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• pp.137-146
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• 2003

Rheumatic diseases can be categorized by pathology into several specific types of musculoskeletal problems, including synovitis (e.g. rheumatoid arthritis), enthesopathy (e.g. ankylosing spondylitis) and cartilage degeneration (e.g. osteoarthritis). Skeletal radiographs have contributed to the diagnosis of these articular diseases, and some disease entities need typical radiographic changes as a factor of the diagnostic criteria. However, they sometimes show normal radiographic findings in the early stage of disease, when there is demineralization of less than 30-50 %. Bone scans have also been used in arthritis, but not widely because the findings are nonspecific and it is thought that bone scans do not add significant information to routine radiography. Bone scans do however play a different role than simple radiography, and it is a complementary imaging method in the course of management of arthritis. The Image quality of bone scans can be improved by obtaining regional views and images under a pin-hole collimator, and through a variety of scintigraphic techniques including the three phase bone scan and bone SPECT. Therefore, bone scans could improve the diagnostic value, and answer multiple clinical questions, based on the pathophysiology of various forms of arthritis.