• International Journal of Contents
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• 제9권2호
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• pp.66-69
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• 2013

In the U.S., performance assessment on the Automatic Exposure Control system (AEC) is managed according to the Mammography Quality Standards Act (MQSA). However, The AEC is not available in the performance assessment conducted in Korea. Also, there is no study made on the performance of the automatic exposure control system for mammography in Korea. For this reason, this study examined the performance of the automatic exposure control system for mammography that was clinically used in the Incheon area. Result showed that the difference of the mean optical density was 0.79 ~ 2.81. This implies that some devices caused unnecessary x-ray exposure to patients. Furthermore, only 61.5% of the entire experimental device was shown to be satisfactory in terms of change in mean optical density. Moreover, in terms of the subject's thickness, change in radiographic density was shown to be severe among lower X-ray tube voltage while there was severe density change in X-ray image depending on X-ray tube voltage among the subjects with more thickness. Therefore, it is suggested to provide performance management on the AEC for mammography.

• 대한방사선기술학회지:방사선기술과학
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• 제47권1호
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• pp.13-19
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• 2024

Control of scattered radiation is one of very important factors in the use of medical radiation. In general X-ray exam, the causes, measurement methods, and the kind of detectors of scattered rays within the radiation area are diverse. In this study, the dose of scattered ray was measured by changing the thickness of the polycarbonate phantom and the tube voltage. As a result of measurement of scattered radiation, the results show that the scattered dose significantly(p<.05) increased with growing of thickness of phantom in the tube voltage 40, 50 and 60 kVp(F(p)<.05, R²>64%). As tube voltage increased at all phantom thicknesses, the scattered dose also significantly(p<.05) increased(F(p)<.05, R²>69%). In cases where a significant correlation was shown, the coefficient of determination of more than 60% was shown in regression analysis. The results of this study can be used as data on scattered radiation dose according to the tube voltage and the object thickness in general X-ray imaging exam.

• 한국방사선학회논문지
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• 제6권1호
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• pp.39-45
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• 2012

기존 구내 치근단 촬영용 장치는 환자 피폭선량, 촬영시 고통 등의 문제점을 지니고 있다. 본 연구에서는 이러한 문제점을 해결하기 위한 신개념의 삽입형 초소형 X선 시스템의 가능성을 검증하였다. 먼저 초소형 X선 튜브에 사용될 콜리메이터와 필터를 설계하기 위하여 Geant4를 이용하여 최적의 콜리메이터 두께와 필터 두께를 결정하였으며 CdTe 검출기와 PX4 모듈을 이용하여 결정된 두께에서의 X선 스펙트럼을 확인하였다. 또한 기존 상용화된 치근단 촬영장치와 XOFT사의 초소형 X선 튜브를 이용하여 제작된 치아 팬텀에 대한 영상을 획득하였다. 그 결과 제안된 신개념의 삽입형 초소형 X선 시스템은 기존 시스템과 유사한 영상의 질을 나타내었다. 이는 향후 치근단 촬영용 장치를 비롯하여 다양한 응용부위에 활용할 수 있음을 나타낸다.

• 대한방사선기술학회지:방사선기술과학
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• 제3권1호
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• pp.43-48
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• 1980

An experimental study was carried out to make a comparison between tube voltage and density of barium sulphate in the stomach radiography. The results were summarized as follows: 1. The percentage of density on concentrations of barium sulphate as contrast media could not show in differences with changes of voltages applied X-ray tube. 2. The changes of density visualized on X-ray film mainly depend upon with thickness of stomach filled barium sulphate than the ratio of barium sulphite and plain water volume. 3. The lesions positioned in upper part within stomach exhibited their best discrimination performanance with depth in the low tube voltage, followed in order by the middle part and lower part. However, the discrimination performanance at the high tension radiography uniformly visualized over X-ray film without density in change.

• 한국방사선학회논문지
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• 제12권3호
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• pp.289-295
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• 2018

대부분의 진단용 방사선 장치는 엑스선을 사용하며, 엑스선은 다양한 에너지를 갖는 스펙트럼을 갖는다. 진단 영상에서 엑스선의 정량적 및 정성적 분석은 선량을 줄이면서 영상 화질을 유지하는데 필수적이다. 본 연구의 목적은 진단 영상에 사용되는 엑스선 스펙트럼을 몬테칼로 시뮬레이션으로 측정하는 것이다. 다양한 엑스선 에너지 스펙트럼이 몬테칼로 시뮬레이션으로 측정되었다. 이 스펙트럼들은 다항식을 보간 한 양극 텅스텐 모델에 의해 계산된 결과와 비교하였다. 엑스선 관전압은 50, 60, 80, 100, 110 kV 였다. 검출기로는 카드뮴 텔루라이드와 비정질 셀레늄 물질을 사용하였다. 엑스선 에너지 스펙트럼의 시뮬레이션 결과는 참조 결과와 일치하였고, NRMSD 값은 최소 1.1%에서 최대 5.7%를 보였다. 시뮬레이션 결과에 의하면 진단 영상을 획득할 때 적절한 관전압의 선택을 가능하게 할 것이다. 또한, 영상 획득 전 환자에 전달되는 선량을 예측하는데 기여할 것이다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 추계학술대회
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• pp.764-765
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• 2010

인체의 진단에 사용되는 의료용 X선 기기는 비 침습적인 방법으로 인체 내부의 진단이 가능하여 의료기관에서 진단에 매우 큰 비중을 차지하고 있다. X선의 발생에 가장 중요한 고전압 발생장치는 기존 변압기 식이 주로 사용되었으나 크고 무거우며 직류 고전압의 리플이 커서 발생효율이 낮다. 이러한 단점을 보완하기 위해 인버터를 사용하여 입력전원의 주파수를 고주파하는 인버터 방식의 고전압 발생장치가 주로 사용되고 있다. 본 연구에서는 펄스폭 변조 방식을 적용하여 관전압과 관전류의 동작을 제어 하였으며, 오실로 스코프를 이용하여 동작 결과를 확인하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2005년도 제29회 학술발표회 초록집
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• pp.93-93
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• 2005

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.418-421
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• 2002

Fundamental study on quasi-monochromatic parallel radiography using a polycapillary plate and a plane-focus x-ray tube is described. The x-ray generator consists of a negative high-voltage power supply, a filament (hot cathode) power supply, and an x-ray tube. The negative high-voltage is applied to the cathode electrode, and the transmission type target (anode) is connected to the ground potential. The maximum voltage and current of the power supply were -100 kV (peak value) and 3.0 mA, respectively. In this experiment, the tube voltage was regulated from 20 to 25 kV, and the tube current was regulated by the filament temperature and ranged from 1.0 to 3.0 mA. The exposure time is controlled in order to obtain optimum film density, and the focal spot diameter was about 10 mm. The polycapillary plate is J5022-21 made by Hamamatsu Photonics Inc., and the outside and effective diameters are 87 and 77 mm, respectively. The thickness and the hole diameter of the polycapillary are 1.0 mm and 25 ${\mu}$m, respectively. The x-rays from the tube are formed into parallel beam by the polycapillary, and the radiogram is taken using an industrial x-ray film of Fuji IX 100 without using a screen. In the measurement of image resolution, we employed three brass spacers of 2, 30, and 60 mm in height. By the test chart, the resolution fell according to increases in the spacer height without using a polycapillary. In contrast, the resolution slightly fell with corresponding increases in the height by the polycapillary. In angiography, fine blood vessels of about 100 ${\mu}$m are clearly visible.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.319-321
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• 2004

The average glandular dose (AGD) is determined by the breast entrance skin exposure, x-ray tube target material, beam quality (half-value layer), breast thickness, and breast composition. Almost breast cancer always arises in glandular breast tissue. As a result, the average radiation absorbed dose to glandular tissue is the preferred measure of the radiation risk associated with mammography. If the normalized average glandular dose is known, the average glandular dose can be computed from the product of the normalized average glandular dose and breast entrance skin exposure. In this study, AGD was calculated by the breast thickness and various x-ray energy (HVL) in 50% glandular 50% adipose breast by Mo.-Rh. assembly. AGD is 84 mrad in compressed 5 cm breast. These results show that as increasing the breast thickness, dose also increases. But as increasing the x-ray tube voltage, dose decreases because of high penetrating ratio through the object. But high tube voltage is reducing the subject contrast. From this result, we have to consider the trade-off between subject contrast of image and dose to the patient and choose proper x-ray energy range.

• 한국정밀공학회지
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• 제32권4호
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• pp.387-394
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• 2015

We analyze heat generation as well as temperature distribution induced by accelerated electron impact on a target in a closed x-ray tube. For the sake of accuracy, we use Monte carlo analysis. This method gives accurate energy deposit in a medium with additional information such as secondary and backscattered electron as well as their paths. A Tungsten coated layer is divided by small rectangular cell which accumulate energy loss of primary electron beam. The cells and their accumulated energy datum are used for the input of finite element analysis. The Maximum temperature rising and temperature distribution were analyzed by transient heat analysis. Some temperature parameters such as target size and coating thickness were varied to investigate temperature sensitivity. Temperatures were compared each other to find primary variable that affect temperature rising on the x-ray target. The results will be helpful in development highresolution x-ray tube and related industries.