• 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).

• 한국콘텐츠학회논문지
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• 제9권3호
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• pp.250-255
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• 2009

본 연구는 경남 김해지역내의 병원에서 사용되고 있는 진단용방사선발생장치 중 일반촬영용장비 40대를 X선관 가변조리개 성능검사와 광조사야와 실제 X선조사야면의 일치검사 및 초점과 가변조리개의 중심선속 일치검사를 통해 장비의 성능을 평가 조사하여 다음과 같은 결과를 얻을 수 있었다. 1. 가변조리개 성능검사에서 최대X선조사야시험 결과는 부적절한 장비가 4대(10%), 최소X선조사야시 험결과에서는 5대(12.5%)로 나타났다. 2. 광조사야와 X선조사야일치시험 결과에서는 최대허용치인 2%이내가 23대(57.5%), 2%이내를 벗어난 장비가 17대(42.5%)로 나타났다. 3. 중심선속 일치시험 결과에서는 완전일치가 11대(27.5%), $0.5^{\circ}$이내로 벗어난 경우는 11대(27.5%), $0.6^{\circ}-1.5^{\circ}$이내가 10대(25%), $1.6^{\circ}-3^{\circ}$이내가 7대(17.5%), $3^{\circ}$이상인 경우가 1대(2.5%)로 나타났다. 결론적으로 가변조리개 중 일부가 기준치에 떨어진 성능상태에서 사용하고 있었으며, 광조사야와 X선 조사야일치상태 및 중심선속 일치에서도 최대허용치를 벗어난 상태에서 상당수의 장비를 사용하고 있었다. 그러므로 피검자의 방사선 피폭을 최소화하고 영상의 질을 향상시키기 위해서는 주기적이고 지속적인 점검평가를 거쳐 노후화 되었거나 부족한 성능상태의 기기를 수리, 보완해야함을 알 수 있었다.

• 치위생과학회지
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• 제14권4호
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• pp.442-447
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• 2014

본 연구는 치과위생사의 이동형 X선 발생장치 관련 업무 특성과 위험지각 수준을 분석하기 위하여 2014년 7월 7일부터 31일까지 이동형 치과 X선 발생장치를 이용하여 촬영을 시행하는 수도권 지역 치과병의원 치과위생사를 대상으로 설문조사를 실시하여 다음과 같은 결과를 얻었다. 이동형 X선 촬영기만 보유한 치과병의원은 25.2%로 이동형 X선 발생장치 1일 10회 이상 촬영이 42.4%였으며, 75.2%는 이동이 어려운 환자, 24.8%는 모든 환자에게 적용하였고, 납 방어복은 환자의 62.6%, 술자의 81.3%가 전혀 착용하지 않았으며, 방사선 안전관리교육 경험률은 59.5%였다. 대상자의 평균 위험자각수준은 3.08점이었다. 위험자각수준은 업무경력 5년 이상 군에 비해 3~4년 미만 군은 66%, 2년 미만 군은 61% 낮았고, 방사선 촬영횟수 5회 미만군은 10회 이상 군보다 72% 낮았으며, 이동형 X선 발생장치만 보유한 군이 고정형 촬영기를 함께 보유한 군보다 3.08배 높은 위험자각수준을 나타냈다. 방사선 업무가 지속될수록 누적선량이 높아지게 되므로 방사선 노출을 최소화하고, 합리적으로 방어하는 노력이 절대적으로 필요할 것으로 생각된다.

• 전력전자학회논문지
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• 제4권1호
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• pp.66-72
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• 1999

본 논문은 고주파 공진형 PWM 인버터식 X-선 장치의 인버터에 단상과 3상 전파정류방식 및 PSU 전원을 연결시켰을 때 나타나는 단시간 출력특성에 대해 분석하였다. X-선의 선질은 X-선관에 입력되는 DC 전압 파형에 의존한다. DC 출력전압 파형은 DC 전압전원의 고조파 왜곡에 의해 영향을 받는다. 이러한 관전압 파형의 왜곡은 X-선 출력의 직선성, 재현성 및 출력선질을 저하시킨다. 따라서 본 논문에서는 DC 출력전압 파형과 세 가지 형식의 DC 입력전원 형식에 따른 출력선량을 비교하였고 이에 따른 실험결과를 검토하였다.

• 터널과지하공간
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• 제27권5호
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• pp.333-342
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• 2017

본 연구에서는 국내의 다양한 화성암에 대해 내부구조의 불균질성을 정량화하고, 이와 탄성파속도 및 점하중강도간의 상관관계를 분석하였다. 3차원 X-ray Computed Tomography(CT)를 통해 암석 시편 내부 구조에 대한 정보를 획득하였으며, 3차원 영상에 통계적 기법을 적용하여 뷸균질성 대표계수(representative unit length, LR)를 계산하였다. 또한 암석의 탄성파 속도 및 점하중강도와 LR간의 상관관계로부터 암석의 역학적 특성치를 예측하는 추정식을 제안하였다. 본 연구에서 제안한 방법을 통해 3차원 X-ray 영상에 기반한 내부 특성 분석값을 이용해 실내실험을 수행하지 않고도 암석의 역학적 물성을 평가할 수 있는 간접적인 인자를 도출할 수 있는 가능성을 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.234-238
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• 1999

In order to radiate X-ray, the low ripple stabilized high voltage DC over the range of 40KV to 150KV is directly inflicted to X-ray tube. The energy characteristics of the radiated X-ray depend on the pulsating waveforms of the DC voltage supplied X-ray tube. In general, the low ripple voltage waveforms with fast rising times are required to increase with the dosage per unit time lest the exposure time should be longer in orde that the motion artifacts of an object may be eliminated in actual. The conventional types of X-ray generators were bulky in physical size and heavy in weight, and the control accuracies of the output voltages were not always satisfactory. The high frequency switching inverter and converter technology on power conversion and control systems have been greatly closed up introducing new power semiconductor devices. To decreasing the volume and the weight of high voltage transformer, and to stabilize ripple, a high frequency PWM inverter is connected between DC source and high voltage transformer. This paper describes the output characteristics according to stabilize ripple of X-ray tube voltage and compared the reproducibility, direcibility and doesage.

• Imaging Science in Dentistry
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• 제47권4호
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• pp.247-254
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• 2017

Purpose: Dual-energy X-ray imaging is widely used today in various areas of medicine and in other applications. However, no similar technique exists for dental applications. In this study, we propose a dual-energy technique for dental diagnoses based on voltage-switching. Materials and Methods: The method presented in this study allowed different groups of materials to be classified based on atomic number, thereby enabling two-dimensional images to be colorized. Computer simulations showed the feasibility of this approach. Using a number of different samples with typical biologic and synthetic dental materials, the technique was applied to radiographs acquired with a commercially available dental X-ray unit. Results: This technique provided a novel visual representation of the intraoral environment in three colors, and is of diagnostic value when compared to state-of-the-art grayscale images, since the oral cavity often contains multiple permanent foreign materials. Conclusion: This work developed a technique for two-dimensional dual-energy imaging in the context of dental applications and showed its feasibility with a commercial dental X-ray unit in simulation and experimental studies.

• 대한방사선기술학회지:방사선기술과학
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• 제41권4호
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• pp.289-295
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• 2018

When using a mobile X-ray unit, primary radiation creates medical images and secondary radiation scatters in many directions, which reduces image quality and causes exposure to patients, care givers and medical personnel. The purpose of this study was to develop a radiation shielding system for effectively shielding secondary radiation and evaluate its effectiveness. Using a mobile X-ray unit, spatial dose according to presence of human equivalent phantom and spatial dose using the developed shielding device were measured, and the phantom at 80 cm equidistance from center of X-ray was compared with spatial dose according to use of a shield. Measurements were taken at intervals of 10 cm every $30^{\circ}$ from the head direction($-90^{\circ}$) to the body direction($+90^{\circ}$). In the spatial dose measurement with and without the phantom, when the human equivalent Phantom was used, the spatial dose was increased by 40% in all directions from 40 cm to 100 cm from the central X-ray, and about 88% of the space dose was reduced when using the developed shields with the phantom. The equidistance dose at 80 cm from the central X-ray was increased by 39% from $5.1{\pm}0.26{\mu}Gy$ to $7.1{\pm}0.15{\mu}Gy$ when the human equivalent phantom was used, and when phantom was used and shielding was used, the spatial dose was reduced by about 90% from $7.1{\pm}0.15{\mu}Gy$ to $0.7{\pm}0.07{\mu}Gy$. The spatial dose of natural radiation was measured to be about $0.2{\pm}0.04{\mu}Gy$ when using the developed shielding with Phantom at a distance of 1 m or more. It is expected that by using the developed shielding system, it will be possible to effectively reduce secondary radiation dose received in all directions and to ensure safe imaging.

• 대한임상독성학회지
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• 제11권2호
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• pp.101-105
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• 2013

Purpose: This study was conducted in order to determine the relationship between the number of portable X-rays and the radiation exposure dose for emergency medical service providers working in the emergency department (ED). Methods: A prospective study was conducted from February 15, 2013 to May 15, 2013 in the ED in an urban hospital. Six residents, seven emergency medical technicians (EMT), and 24 nurses were enrolled. They wore a personal radiation dosimeter on their upper chest while working in the ED, and they stayed away from the portable X-ray unit at a distance of at least 1.8 m when the X-ray beam was generated. Results: The total number of portable x-rays was 2089. The average total radiation exposure dose of emergency medical service providers was $0.504{\pm}0.037$ mSv, and it was highest in the EMT group, 0.85(0.58-1.08) mSv. The average of the total number of portable X-rays was highest in the doctor group, 728.5(657.25-809). The relationship between the number of portable X-rays and the radiation exposure dose was not statistically significant(-0.186, p=0.269). Conclusion: Under the condition of staying away from the portable X-ray unit at a distance of least 1.8 m, the relationship between the number of portable X-rays and the radiation exposure dose was not statistically significant.

• International Journal of Concrete Structures and Materials
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• 제5권2호
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• pp.113-117
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• 2011

The purpose of this work is the comparative study for grinding of two cement clinkers. X-ray fluorescence, physical and granulometric tests and optical microscopy were used to characterize the clinkers. Also grinding tests were carried out for ten samples to determine the parameters influencing grindability of its clinkers. The results of calculation of the energies of grinding according to the law developed by Von Rittinger and the study of the microstructure of the two clinkers shows good agreements. Indeed, frequent clusters of belite which indicate a lack of uniformity and fineness have an effect on lowering the grindability. The obtained analyses and the results enabled us to interpret the granulometry and the microstructure of clinker to control quality and resistance.