• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3117-3122
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• 2011

Skull A-P projections are the bi-product where the ESD (Entrance Surface Dose) for digital radiography is much higher than that conventional screen-film radiography. Therefore, the aim of this study was to reduce radiation doses to patients by using an added filter. This research focuses on the identification of the reduction of exposure to radiation based on the thickness of an added filter when applying the 'Skull A-P Projection' by using the 'Skull Phantom'. Also, an experiment was conducted to evaluate the qualitative decline of images through filtration. The measurement of one's exposed dose to radiation was executed by locating the 'Skull Phantom' on the position of the 'Skull AP,' while changing 16 kinds of added filters from 0.1 mmAl to 0.5 mmCu + 2.0 mmAl in terms of incident and penetrating doses. For the qualitative evaluation of images, a total number of 17 images have been acquired in the 'Skull Phantom' under the same conditions as those for the measurement of one's exposed dose. The acquired images have been evaluated by a radiological specialist. As a result, the images with a diagnostic value have been obtained by using such added filters as the compound filter of 0.2 mmCu +1.0 mmAl. The exposed dose absorbed on the 'Skull Phantom' is about 0.6 mGy. The value is only 12% of 5 mGy, the ESD value acquired on the 'Skull P-A Projection', which is recommended by the International Atomic Energy Agency (IAEA). As a result, depending on the parts of inspection, it is possible to reduce the patient's exposed dosage of radiation considerably by using an appropriate added filter.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4429-4436
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• 2013

Measurements of CNR(Contrast to Noise Ratio) and SNR(Signal to Noise Ratio) of T-spine breathing technique (TBT) using spontaneous breathing and T-spine exhalation technique (TET) with full exhalation were carried out, and with which the more appropriate method was suggested. Both TBT and TET were examined in a sample of fifty-three patients who visit to our hospital for spinal disease from June 2012 to November 2012. All images were evaluated with CNR measured from the differences between the mean pixels and contrast density as setting ROI of spinous process, pedicle, vertebral body, intervertebral foramen, and intervertebral disk using Image J. SNR was measured with the mean pixels and the standard deviation as setting ROI of vertebral body using Image J. In CNR comparison and SNR comparison of TET and TBT, TBT was indicated as excellent in ROI of pedicle, vertebral body, intervertebral foramen and intervertebral disk, and statistical analysis were significant(p<.01). As TBT indicated excellent images compared to the existing T-spine lateral radiography, T-spine lateral radiography would be reestablished and significant as applying to various medical institutions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3517-3523
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• 2010

Single exposure dual X-ray imaging can be used to separate soft and dense-material images for medical and industrial applications. This study keep focusing baggage inspection system(BIS) specifically. New detector modules for single exposure dual X-ray imaging are consisted of low energy detector (LED) and high energy detector (HED). First, the optimized thickness of copper filter coupled HED to separate low energy and high energy was simulated by the given X-ray energy (140 kVp, 1 mA) using Monte Carlo simulation codes, MCNPX. So as a result of simulation, the copper filter thickness is 0.7 mm. For the design of PIN photodiode, ATLAS device simulation tool was used. 16 channels PIN photodiode of 1.5 mm ${\times}$ 3.2 mm for Dual X-ray imaging detector was fabricated in the process of ETRI. And its dark current and quantum efficiency, terminal capacitance were measured. It was proven that the Lanex Fast B coupled HED were a sufficient candidate to replace the CsI(Tl) commerced in dual X-ray system, since these give a strong signal, overcoming system noise. Finally dual X-ray image was acquired through correction of the LED X-ray Image and the HED X-ray Image.

• Investigative Magnetic Resonance Imaging
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• v.13 no.1
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• pp.74-80
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• 2009

Purpose : To evaluate the characteristic MR imaging findings of Langerhans cell histiocytosis (LCH) in the skull and to compare them with those of plain radiography and computed tomography. Materials and Methods : A total of 10 lesions in 9 patients (Age range; 5-42 years, Mean age; 18, all women) with Langerhans cell histiocytosis in the skull were included in our study. Nine lesions in nine patients were histologically confirmed by surgery or fine needle aspiration biopsy. All patients performed with MRI, and plain radiography and CT scan were done in 7 patients (8 lesions). Two experienced neuroradiologists reviewed the radiological examinations independently with attention to location, size, shape and nature of the lesions in the skull and compared the extent and extension of the lesions to adjacent structures. Results : The lesions were distributed in all of the skulls without predilection site. On MRI, the masses were shown as well-enhancing soft tissue masses (10/10) mainly in diploic spaces (8/10) with extension to scalp (9/10) and dura mater (7/10). Dural enhancement (7/10) and thickening (4/10) were seen. The largest diameter of the soft tissue masses ranged 1.1 cm to 6.8 cm, shaped as round (5/10) or oval (5/10). On CT scans, the lesions were presented as soft tissue masses involving diploic space (6/8) and scalp extension (7/8) were also well visualized. Although bony erosion or destruction was more clearly seen on CT rather than those of MRI, enhancement of soft tissue masses and dura were not well visualized on CT. In contrast, all of the lesions in LCH were seen as punched out (4/8), beveled-edge appearance (4/8) osteolytic masses in plain radiography, but scalp and dural extension could not be seen. Conclusion : Characteristic MR findings in patients with LCH are soft tissue mass in diploic space with extension to dura and scalp, and MRI would be better imaging modality than plain radiography or CT.

• 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 Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6932-6939
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• 2015

The respiration is one of important factor in the radiation therapy. The existing commercial method of cone-beam computed tomography on LINAC does not consider respiratory motion of patient hence the images are both distorted and inaccurate. In this study, the cone-beam computed tomography images have been reconstructed from back projection radiography of specific phase on breathing cycle which concerned about respiratory movement in radiation therapy. This study investigated how different between cone-beam CT images with and without gating respiratory movement, and this paper provides that guide and implementation of gated cone-beam CT on radiation therapeutic equipment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6019-6026
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• 2015

In this study, we have tried to use 3D-printing technology, which is very useful for small amount production and individual personalization manufacturing to produce a cast customized by individual. To do this, we have made casts by the 3D printer in the method of fused deposition modeling technique using ABS(acrylonitrile butadiene styrene) resin which is thermoplastic plastics. The computed tomography of human hand part was used as the modeling of the cast and it was designed to circulate air well. As a result, an individual personalized cast that fitted well with the model part was produced. In addition, we could get more excellent radiography from the cast than the existing cast. In conclusion, this study of 3D-printing could be used as basic data when a similar designed structure in fused deposition modeling technique by ABS resin is printed out.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.3
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• pp.355-365
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• 2015

Objectives: This study was conducted to better understand the relationship between health effects and exposure to dusts from a briquette fuel complex in Ansim, Daegu, Korea. Methods: The subjects of this study consisted of 2,980 persons over 40 years old who had lived 20 years or more around a briquette fuel complex in Daegu. We conducted a questionnaire survey, and chest radiography was performed. In addition, chest computed tomography(CT) (335 cases) and pulmonary function test(PFT) (658 cases) were done. Pneumoconiosis was diagnosed if one of three radiologists determined(or suspected) pneumoconiosis. We also conducted in-depth interviews for pneumoconiosis cases. We defined the exposed group as subjects residing within a 500 meter radius from the walls of the briquette fuel complex, and the others were defined as the control group. Results: Subjects in the exposed and control groups are respectively 715(24%) and 2,265 cases(76%). Major respiratory symptoms in the exposed group such as sputum, dyspnea, chest tightness and wheezing were significantly higher than in the control group. By chest radiography, 173 cases of pneumoconiosis or suspicious pneumoconiosis were detected. By PFT, 62 cases(29.5%) of chronic obstructive pulmonary disease(COPD) among 210 asymptomatic subjects were detected. Finally, by chest CT we concluded 28 cases to be pneumoconiosis, and eight cases among them proved to be pneumoconiosis by environmental exposure. Conclusions: Through this study, we concluded that health outcomes such as respiratory symptoms, pneumoconiosis, and COPD were caused by continuous exposure to dusts from the briquette fuel complex. Policies to reduce environmental exposure are needed, and cases of environmental disease should be intensively followed up by the government.

• Journal of Veterinary Clinics
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• v.25 no.3
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• pp.187-191
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• 2008

A 7-year-old, intact female Yorkshire terrier dog was presented for coughing, anorexia, chest pain and dyspnea. Right lateral thoracic radiograph demonstrated a large mass shape on the heart base with decreased cardiac silhouette and severe right deviation of the trachea with the heart shifted to the left thoracic wall was observed on the ventrodorsal thoracic projection. Echocardiographic examination revealed a large rounded mass compressing left atrium around the heart base without signs of pericardial effusion. On computed tomographic (CT) findings, sagittal CT images depicted the possibility of cranial vena caval invasion and heart base involvement of the mass associated with biatrial compression. Dorsal CT image revealed the right deviation of trachea due to the heart base mass and markedly shrunk lung space was detected on the transverse CT image. Because the dog suddenly had died during the recovery from anesthesia after finishing CT scan, necropsy was performed. On gross findings, a large and lobulated mass was located at the base of the heart. A poorly-demarcated, infiltrative, multilobulated tumor composed of polyhedral cells in solid cellular sheets was confirmed based on histopathologic examination. This dog was diagnosed as a chemodectoma. This case report describes the clinical findings, diagnostic consistency of thoracic radiography, echocardiography and CT, and histopathologic confirmation in a spontaneously occurring chemodectoma with a Yorkshire terrier dog.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.1
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• pp.25-32
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• 2008

[ $^{169}Yb$ ] industrial NDT sealed sources were developed by using $Yb_2O_3$ pellets as the target and demonstrated for their performance. To produce the pellets, optimal compacting and sintering conditions were determined experimentally. Source holders for $^{169}Yb$ were designed and fabricated. After assembling an active source produced from HANARO with the developed source holder, a demonstration experiment was performed to compare the quality of the radiographs from $^{192}Ir$ and soft X-rays. This demonstration study showed that the developed $^{169}Yb$ produced better radiographs than $^{192}Ir$ for a carbon steel with less than a 4 mm thickness.