• Journal of Radiation Protection and Research
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• 제41권3호
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• pp.229-236
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• 2016

Background: In order to manage the patient exposure dose in X-ray diagnosis, it is preferred to evaluate the entrance skin dose; although there are some evaluations about entrance skin dose, a small number of report has been published for direct measurement of patient. We think that a small-type optically stimulated luminescence (OSL) dosimeter, named nanoDot, can achieve a direct measurement. For evaluations, the corrections of angular and energy dependences play an important role. In this study, we aimed to evaluate the angular and the energy dependences of nanoDot. Materials and Methods: We used commercially available X-ray diagnostic equipment. For angular dependence measurement, a relative response of every 15 degrees of nanoDot was measured in 40-140 kV X-ray. And for energy dependence measurement, mono-energetic characteristic X-rays were generated using several materials by irradiating the diagnostic X-rays, and the nanoDot was irradiated by the characteristic X-rays. We evaluated the measured response in an energy range of 8.1-75.5 keV. In addition, we performed Monte-Carlo simulation to compare experimental results. Results and Discussion: The experimental results were in good agreement with those of Monte-Carlo simulation. The angular dependence of nanoDot was almost steady with the response of 0 degrees except for 90 and 270 degrees. Furthermore, we found that difference of the response of nanoDot, where the nanoDot was irradiated from the randomly set directions, was estimated to be at most 5%. On the other hand, the response of nanoDot varies with the energy of incident X-rays; slightly increased to 20 keV and gradually decreased to 80 keV. These results are valuable to perform the precise evaluation of entrance skin dose with nanoDot in X-ray diagnosis. Conclusion: The influence of angular dependence and energy dependence in X-ray diagnosis is not so large, and the nanoDot OSL dosimeter is considered to be suitable dosimeter for direct measurement of entrance surface dose of patient.

• Journal of Radiation Protection and Research
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• 제34권1호
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• pp.31-36
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• 2009

일부지역의 병원에 설치, 운영되고 있는 진단용 X선 발생장치틀 의원, 병원, 종합병원별로 관 전압, 관 전류/량, 조사기간, 조사선량 성능을 평가하여 측정방법과 기술을 배우고 중요성을 알리고자 한다. 진단용 X선발생장치를 그룹별로 10대씩 총 30대에 대하여 관전류/량, 조사시간측정기를 사용하여, 백분율평균오차로 평가하였고 그에 따른 조사선량의 재현성은 변동계수를 계산하여 평가하였다. 진단용 X선 발생장치 30대 중 부적합한 장치는 관전압정확도 시험에서 5대(16.7%), 관전류정확도시험에서 3대(10,0%), 관전류량정확도 시험에서는 4대(13.3%), 조사시간정확도 시험에서는 5대(16.7%), 조사선량의 재현성 시험에서는 7대(23.3%)로 조사되었다. 진단용 X선 발생장치를 관리규정에 의거하여 성능검사 결과에 의해 성능관리의 심각성을 알 수 있었고, 이에 주기적으로 실시하여야 함은 물론 안전하게 관리함으로써 환자 및 방사선관계종사자에 대하여 방사선으로 인한 방사선 피폭경감, 화질영상관리, 재촬영 감소 둥에 의해 환자에게 양질의 의료서비스를 제공하게 될 것이다. 따라서 정기적인 성능검사가 필요하다고 사료된다.

• 대한방사선기술학회지:방사선기술과학
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• 제16권1호
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• pp.101-106
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• 1993

In order to assure safety of both patient and operator, and to provide uniform quality radiographs, it is necessary to perform periodic calibration of diagnostic X-ray equipment. A basic parameter of diagnostic equipment's and its image sharpness is the size(and shape the energy distribution) of the focal spot as viewed along the central X-ray beam. This size determines the resolution possible with the equipment and also determines the heat characteristics of an anode. A fine focus tube gives high resolution but causes high local heating of target. In past, the pin-hole and star pattern image measurement for evaluation of resolution have been widely used, but it produced blurring and inaccuracy of image. So newly inverted Ug-meter has advantage in more convenient measurement method and less out-put bias than other image measurement. The authors intended to compare measured focal size between Ug-meter and focal spot test tool, changed state from setting to now of units.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.426-426
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• 2009

Diagnostic X-ray system is general and basic medical equipment to be used in mostly medical organizations, but being bombed of radioactivity is a big weak point when irradiates a X-ray to the human body so that ICRP restricted the radiation exposure tolerance of the human body. In order to reduce being bombed, the many research and development is now advanced. A lots of diagnostic X-ray machines have currently used due to the increase of occurrence efficiency of X-ray and precisely the output control by using the inverter which is a high speed switching semiconductors. For getting the confidence of the X-ray machine, the same radiation occurrence, same evaluation, and same irradiation condition are necessary when evaluates X-ray irradiation. It is the most important part for the accuracy of the test result and the patient safety. This paper has produced the high voltage occurrence system of full-wave rectification method by using the LC resonance inverter, and evaluated the irradiation reproducibility in order to use it in diagnosis of the patient.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.330-332
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• 1997

The absorption coefficient of contrast media was measured region of diagnostic X-ray. Relative values of absorption coefficient was found the largest peak in the range of $60{\sim}70kVp$ for sodium sulfate and 60kVp for iodine. Increasing the thickness of contrast media and patient, the values of absorption coefficient was rising.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.379-382
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• 2002

Lately, intensifying screen of the $CaWO_4$ is used to medical treatment and diagnosis of the image. In this paper, we investigated transmission fraction and mass attenuation coefficient of $CaWO_4$ screen about diagnostic x-ray of low energy using MCNP 4C code. Experimentally, for 0.9 mm-$CaWO_4$ screen, the absorbable rate of diagnostic x-ray is more than 95%. according to kVp, the experimental value of mass attenuation coefficient is in a1most agreement with an corrected estimate value of MCNP and the deviation of experimental values is less than ${\pm}7%$. Using the MCNP code through this paper, we can make an estimate of signal and design for construction of the CaWO4/a-Se based digital x-ray image detector and make a good use of the foundation data for development of other materials.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2010년도 춘계학술대회
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• pp.231-237
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• 2010

The purpose of this study was to investigate the actual conditions of radiation safety supervision in animal clinics using quality assurance (QA) and quality control (QC) of diagnostic X-ray units. The surveys for QA/QC, equipment condition, and safety supervision were carried out in 18 animal clinics randomly. The QA/QC included reproducibility of dose exposure, kVp, mAs, collimator accuracy test, collimator luminance test, X-ray view box luminance test, grounding system equipment test and external leakage current test. As a result, 44.44% of reproducibility of dose exposure was proper, 81. 25% of kVp test was good, and 100% of mAs test was appropriate. Also, 66.66% of collimator accuracy test was proper, 61.11% of collimator luminance test was good, 53.13% of X-ray view box luminance test was suitable. In addition, only 5.55% of grounding system equipment and ground resistance was proper, 63.64% of external leakage current test was appropriate in grounding system equipment test.

• 대한방사선기술학회지:방사선기술과학
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• 제42권5호
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• pp.365-371
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• 2019

We have developed and applied a diagnostic Multi-Leaf Collimator (MLC) to optimized the X-ray field in medical imaging and the usefulness evaluated through the fusion of infrared image and X-ray image acquired by infrared camera. The hand and skull radiography with multi-leaf collimator(MLC) showed significant area dose reductions of 22.9% and 31.3% compared to ARC and leakage dose was compliant with KS A 4732. Also scattering doses of 50 cm and 100 cm showed a significant decrease to confirm the usefulness of MLC. It was confirmed that the fusion of infrared images with an adjustable degree of transparency was possible in the X-ray images. Therefore, fusion of anatomical information with physiological convergence is expected to contribute and improvement of diagnostic ability. In addition, the feasibility of convergence X-ray imaging and DITI devices and the possibility of driving MLC with infrared images were confirmed.

• 대한방사선기술학회지:방사선기술과학
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• 제22권1호
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• pp.73-78
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• 1999

The purposes of this study are to analyze the realities after enforcements of safety control regulations for diagnostic X-ray equipments and to suggest means for an improvement of low radiation safety control. A questionnaire survey for medical radiologic technologists was carried out to determine enforcement effects of the safety control regulations. The results of analysis from the survey are as follows. That is, most of the respondents realized the importance of the radiation safety control system, but about a half of them revealed that the regulations were not well observed in accordance with their purposes. Only 43.9% of the respondents took an active part in quality control and safety control of radiation. And respondents responsibility, sex, age, and knowledge for safety control were important indicators for observations of the regulations. Trainings for the safety control regulations are needed to ensure safety control and proper usage of diagnostic X-ray equipments. And management of organizations using diagnostic X-ray equipments have to understand and stress the importance of radiation safety control system.

• 대한방사선기술학회지:방사선기술과학
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• 제18권2호
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• pp.61-73
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• 1995

For the managements of the diagnostic X-ray equipments, the authors examined the output of single phase rectification assembly, Three phase rectification assembly and serial radiographic appartus, and got the following conclusions. 1. When the tube voltages in X-ray control panels ware compared to the measured values on the kVp pulse meter, only little differences were detected in all the X-ray equipments. And most of the equipments were all well managed within the internationally permitted limits, excepting the 12.02 % error at 120 kVp in three phase rectifying assembly. 2. As for the X-ray qualities affecting the X-ray images, the serial radiographic apparatus showed excellence, while the single phase rectification assembly were somewhat inferior to the others only maining the internationally recommended limits. 3. The tube voltage ranges where the X-ray output showed excellence were $100{\sim}200\;mA$ in serial radiographic apparatus, $200{\sim}350\;mA$ in three phase rectification assembly and $350{\sim}400\;mA$ in single phase rectification assembly respectively. 4. In the repeatability test of the X-ray equipments, CVs were in the range of $0.0029{\sim}0.049$, which is within the HEW or KS standards. Consequently all the equipments are thought to be well-manage. 5. This study on characteristics and output of the X-ray equipments was accomplished within a limited short time. Long-time researches on the function managements for the X-ray equipments should be followed along with the periodical checking the output for reduction of X-ray exposures to the patients or radio-technologists, and for maintanance and prediction of trouble of the equipments.