• 한국산업융합학회 논문집
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• 제11권4호
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• pp.195-199
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• 2008

The carbon fiber has low x-ray absorption property and high stiffness. This is the reason why many CT(Computed Tomography) manufacturer use carbon fiber in couch tabletop for CT scanner. In this paper, we design and make the couch tabletop made of carbon fiber composite, and verify the validity in CT scanner. In designing the couch tabletop, to determine the aluminum equivalent thickness of couch tabletop, we evaluate X-ray the transmissivity of aluminum and carbon plate in 80-120kVp X-ray energy range. And we perform structural analysis and mechanical design using determined thickness of carbon sheet. In conclusion, it was evaluated that manufactured couch tabletop satisfies X-ray transmissivity and mechanical requirements in CT scanner.

• Journal of International Society for Simulation Surgery
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• 제3권1호
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• pp.16-21
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• 2016

Computed tomography (CT) can completely digitize the interior and the exterior of nearly any object without any destruction. Generally, the resolution for industrial CT is below a few microns. The industrial CT scanning, however, has a limitation because it requires long measuring and processing time. Whereas, 2D X-ray imaging is fast. In this paper, we propose a novel concept of 3D non-destructive inspection technique using the advantages of both micro-CT and dual X-ray images. After registering the master object’s CT data and the sample objects’ dual X-ray images, 3D non-destructive inspection is possible by analyzing the matching results. Calculation for the registration is accelerated by parallel computing using graphics processing unit (GPU).

• Korean Journal of Radiology
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• 제24권10호
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• pp.947-948
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• 2023

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.559.1-559
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• 2001

The aim of the study was to determine the direction and the rate of polymerization shrinkage of light-cured resin composite. Materials and Methods: A microfocus x-ray CT(computed tomography) instrument (SMX-255CT, Shimadzu Co., Kyoto, Japan) was used to analyze and characterize the pre-and post-gel phases. A microfocus x-ray tube was used to enable a focus dimension of 4 microns.(omitted)

• Imaging Science in Dentistry
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• 제31권3호
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• pp.165-173
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• 2001

Objectives : To evaluate the absorbed and effective doses of spiral and computed tomography for the dental implant planning. Materials and Methods: For radiographic projection, TLD chips were placed in 22 sites of humanoid phantom to record the exposure to skin and the mean absorbed dose to bone marrow, thyroid, pituitary, parotid and submandibular glands and nesophagus. Effective dose was calculated, using the method suggested by Frederiksen et al.. Patient situations of a single tooth gap in upper and lower midline region, edentulous maxilla and mandible were simulated for spiral tomography. 35 axial slices (maxilla) and 40 axial slices (mandible) with low and standard dose setting were used for computed tomography. All the radiographic procedures were repeated three times. Results: The mean effective dose in case of maxilla was 0.865 mSv, 0.452 mSv, 0.136 mSv and 0.025 mSv, in spiral tomography of complete edentulous maxilla, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). That in case of mandible was 0.614 mSv, 0.448 mSv, 0.137 mSv and 0.036 mSv, in spiral tomography of complete edentulous mandible, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). Conclusions: Based on these results, it can be concluded that low mAs computed tomography is recommended instead of spiral tomography for the complete edentulous maxilla and mandible dental implant treatment planning.

• Journal of Korean Neurosurgical Society
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• 제64권5호
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• pp.784-790
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• 2021

Objective : The purpose of this study was to investigate the correlations among various radiological parameters used to determine cervical alignment from cervical spine radiographs (X-CS) and cervical spine computed tomography (CT-CS), both within and between modalities. Methods : This study included 168 patients (≤60 years old) without a definite whole spine deformity who underwent CT-CS and X-CS. We measured occipital slope (O-s), C1 slope, C2 slope, C7 slope, sella turcica - C7 sagittal vertical axis (StC7-SVA), spino-cranial angle, T1 slope, and C27-SVA. We calculated the O-C2 angle, O-C7 angle, and C2-7 angle from the measured parameters and conducted correlation analyses among multiple parameters. Results : The intrinsic correlation features among multiple cervical parameters were very similar for both X-CS and CT-CS. The two SVA parameters (C27-SVA and StC7-SVA) were mainly influenced by the upper cervical slope parameters (r=|0.13-0.74|) rather than the lower slope cervical parameters (r=|0.08-0.13|). The correlation between X-CS and CT-CS for each radiological parameter was statistically significant (r=0.26-0.44) except for O-s (r=0.10) and StC7-SVA (r=0.11). Conclusion : The correlation patterns within X-CS and CT-CS were very similar in this study. The correlation between X-ray and CT was statistically significant for most radiological parameters, and the correlation score increased when the horizontal gaze was consistently maintained. The lower cervical parameters were not statistically associated with translation-related parameters (C2-7 SVA and StC7-SVA). Therefore, the upper cervical segment may be a better predictor for determining head and neck translation.

• 대한방사선기술학회지:방사선기술과학
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• 제41권1호
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• pp.7-12
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• 2018

Patients who visit the emergency room with urinary stones have difficulty lying down in a supine position due to severe pain when performing the KUB test. The purpose of this study was to find methods to reduce the patients' pain and image distortion, and obtain medical images with high diagnostic values. After checking the standard classification of disease and cause of death, the target group consisted of 121 patients who had clearly distinguished stones from computed tomography. Patients with stones in the ureteralvesical junction were excluded. Qualitative image evaluation was performed by confirming the location of the stone in the computed tomography images. and evaluated the rate of visual discrimination of stones possible through KUB and abdominal plain X-ray. Quantitative image evaluation was performed on the KUB, abdominal plain X-ray images. The transverse process of the first lumbar vertebrae served as the standard point, and the length from this point to the lower part of the stone was measured. Results from looking at the rate of visual discrimination of stones possible through KUB and abdominal plain X-ray showed: 94 patients (77.6%) for KUB images and 91 patients (75.2%) for computed tomography images. The standard deviation for KUB and abdominal X-ray was 3 (2.4%). Comparing and analyzing the location from KUB images and abdominal plain X-ray images, the stone position was 10.1 mm in the kidney, 10.5 mm in the ureteropelvic junction, and 9.7 mm in the ureters. It was shown that the stone moved 10 mm on average with significant statistical difference (P<0.05). In cases where the pain is so severe that it is impossible to perform the test in the supine position, an alternative may be to check the stone position by performing a modified KUB test by having the patient stand in a vertical position. In the future, this will provide convenience to both the examiner and the patient when performing the examination, and it will contribute with its reproducibility.

• Journal of Radiation Protection and Research
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• 제47권1호
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• pp.39-49
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• 2022

Background: For proper monitoring of the eye lens dose, an appropriate calibration factor of a dosimeter and information about the mean energies of X-rays are indispensable. The scattered X-ray energy spectra should be well characterized in medical practices where eye lenses of medical staffs might be high. Materials and Methods: Scattered X-ray energy spectra were experimentally derived for three different types of X-ray diagnostic and therapeutic equipment, i.e., the computed tomography (CT) scan, the angiography and the fluoroscopy. A commercially available CdZnTe (CZT) spectrometer with a lead collimator was employed for the measurement of scattered X-rays, which was performed in the usual manner. Results and Discussion: From the obtained energy spectra, the mean energies of the scattered X-rays lied between 40 and 60 keV. This also agreed with that obtained by the conventional half value layer method. Conclusion: The scattered X-rays to which medical workers may be exposed in the region around the eyes were characterized by means of spectrometry. The obtained mean energies of the scattered X-rays were found to match the flat region of the dosimeter response.

• 대한치과의사협회지
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• 제50권4호
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• pp.180-188
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• 2012

Cone beam computed tomography(CBCT) machines recently developed in Korea, being designed for imaging hard tissues of the oral and maxillofacial region. I reported a brief overview of CBCT system, in comparison with coventional computed tomography(CT) system. CBCT provides high resolution, simpler image acquisition, lower dose and cost alternative to conventional CT, promising to revolutionize the practice of oral and maxillofacial radiology.

• 대한의용생체공학회:의공학회지
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• 제25권2호
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• pp.97-102
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• 2004

소 동물 촬영에 이용될 수 있는 고해상도의 x-선 cone-beam micro computed tomography (micro-CT) 시스템을 개발하였다 Micro-CT 시스템은 120${\times}$120 mm2 의 2차원 평판 x-선 감지기, micro-focus x-선 발생장치, 주사 기구부, 병렬처리 영상 재구성 시스템으로 이루어져 있다. 개발된 시스템의 성능을 평가하기 위해 대조도와 공간해상도를 측정하였다. 대조도 실험에서는 95 mGy 에서 36 CT-번호를 구별할 수 있음을 확인하였고, 공간 해상도 실험에서는 14 lp/mm 의 성능을 확인하였다. 소 동물 촬영 결과로 실험용 쥐의 대퇴부, 심장 그리고 복부 동맥 혈관을 촬영한 경상을 제시하였다. 개발된 micro-CT 시스템은 소 동물을 이용한 생명공학 분야 연구에 널리 이용될 수 있을 것으로 기대된다.