An Assessment of the Radiation Dose from Radiography with the Change in Air Gap

Byeong Ju Ahn(안병주) 한국방사선학회 2016 한국방사선학회 논문지 Vol.10 No.6

본 연구에서는 공극 기법의 고관전압 촬영에서 격자를 사용한 것과 같은 화질을 유지하면서 선량을 줄이는 방안을 제안하고자 하였다. 실험은 초점과 수용체와의 거리 180 cm에서 공극을 10 cm, 15 cm, 20cm, 25 cm, 30 cm으로 하였으며 각각의 공극 거리에서 관전류를 15 mAs로 고정하고 관전압은 80 KvP,85 kVp, 90 kVp, 95 kVp, 100 kVp로 하여 촬영을 하였다. 전통적인 방법인 격자를 사용하였을 때 촬영은 초점과 수용체와의 거리 180 cm에서 15 mAs, 107 kVp로 하였다. 실험결과 격자를 사용하여 촬영하였을때 표면선량은 0.130 R로 나타났고 공극을 20 cm로 하였을 때의 표면선량은 0.124 R로 나타났으며 두 영 상 간의 PSNR은 10.65 [dB]로 나타났다. 결론적으로 표면선량이 적으면서 산란선을 제거하여 격자를 사용하였을 때와 유사한 화질을 유지할 수 있는 공극의 거리는 20 cm로 나타났다. 연구의 결과는 공극을 이용한 방사선촬영에서 표면선량을 제거할 수 있는 지표로 사용할 수 있을 것으로 사료된다. 결론적으로 표면선량이 적으면서 산란선을 제거하여 격자를 사용하였을 때와 유사한 화질을 유지할 수 있는 공극의 거리는 20 cm로 나타났다. 연구의 결과는 공극을 이용한 방사선촬영에서 표면선량을 절감할 수 있는 지표로사용할 수 있을 것으로 사료된다. This study aims to propose a method for reducing radiation dose in high-voltage radiography using air gap technique while maintaining the same image quality as when using grids. For an experiment, air gaps were set at 10 cm, 15 cm, 20 cm, 25 cm, and 30 cm with a focus-receptor distance of 180 cm; with each air gap distance, tube current was set at 15 mAs, and tube voltage was set at 80 kVp, 85 kVp, 90 kVp, 95 kVp and 100 kVp. Then, radiographs were taken. In a situation of employing a conventional method of using grids, radiographs were taken at 15 mAs and 107 kVp with a focus-receptor distance of 180 cm. According to the results of the experiment, the surface radiation dose from radiography using grids was 0.130 R; the surface radiation dose at a 20cm air gap was 0.124 R; PSNR between these two images was 10.65 [dB]. In conclusion, the air gap distance, which could maintain the image quality similar to that of a case where scattered radiation was removed and grids were used with a small surface radiation dose, was 20 cm. The result of this study is thought to be used as an indicator to remove surface radiation dose in radiography using air gap.

공극(氣隙) 변화에 따른 방사선촬영 선량평가

안병주 ( Byeong Ju Ahn ) 한국방사선학회 2016 한국방사선학회 논문지 Vol.10 No.6

본 연구에서는 공극 기법의 고관전압 촬영에서 격자를 사용한 것과 같은 화질을 유지하면서 선량을 줄이는 방안을 제안하고자 하였다. 실험은 초점과 수용체와의 거리 180 cm에서 공극을 10 cm, 15 cm, 20 cm, 25 cm, 30 cm으로 하였으며 각각의 공극 거리에서 관전류를 15 mAs로 고정하고 관전압은 80 KvP, 85 kVp, 90 kVp, 95 kVp, 100 kVp로 하여 촬영을 하였다. 전통적인 방법인 격자를 사용하였을 때 촬영은 초점과 수용체와의 거리 180 cm에서 15 mAs, 107 kVp로 하였다. 실험결과 격자를 사용하여 촬영하였을 때 표면선량은 0.130 R로 나타났고 공극을 20 cm로 하였을 때의 표면선량은 0.124 R로 나타났으며 두 영상 간의 PSNR은 10.65 [dB]로 나타났다. 결론적으로 표면선량이 적으면서 산란선을 제거하여 격자를 사용하였을 때와 유사한 화질을 유지할 수 있는 공극의 거리는 20 cm로 나타났다. 연구의 결과는 공극을 이용한 방사선촬영에서 표면선량을 제거할 수 있는 지표로 사용할 수 있을 것으로 사료된다. 결론적으로 표면선량이 적으면서 산란선을 제거하여 격자를 사용하였을 때와 유사한 화질을 유지할 수 있는 공극의 거리는 20 cm로 나타났다. 연구의 결과는 공극을 이용한 방사선촬영에서 표면선량을 절감할 수 있는 지표로 사용할 수 있을 것으로 사료된다. This study aims to propose a method for reducing radiation dose in high-voltage radiography using air gap technique while maintaining the same image quality as when using grids. For an experiment, air gaps were set at 10 cm, 15 cm, 20 cm, 25 cm, and 30 cm with a focus-receptor distance of 180 cm; with each air gap distance, tube current was set at 15 mAs, and tube voltage was set at 80 kVp, 85 kVp, 90 kVp, 95 kVp and 100 kVp. Then, radiographs were taken. In a situation of employing a conventional method of using grids, radiographs were taken at 15 mAs and 107 kVp with a focus-receptor distance of 180 cm. According to the results of the experiment, the surface radiation dose from radiography using grids was 0.130 R; the surface radiation dose at a 20cm air gap was 0.124 R; PSNR between these two images was 10.65 [dB]. In conclusion, the air gap distance, which could maintain the image quality similar to that of a case where scattered radiation was removed and grids were used with a small surface radiation dose, was 20 cm. The result of this study is thought to be used as an indicator to remove surface radiation dose in radiography using air gap.

설문조사방법을 사용한 국내 공공발주 건설사업관리 프로젝트의 성과측정

유병기(Yoo Byeong-Gi),안병주(Ahn Byung-Ju),김재준(Kim Jae-Jun) 대한건축학회 2008 大韓建築學會論文集 : 構造系 Vol.24 No.10

The modern construction projects have become larger, more complicated and specialized than before. In these projects, the risks on delay, over budget and poor quality exist. However, the traditional construction delivery system is not likely to cope with the problem due to the ambiguous responsibility for managing time, cost and quality over the project life-cycle. Construction Management (CM) is an efficient delivery system for managing the problem. Since enactment of CM in 1996, CM market in Korea has shown increase by growing the amount of orders received. Experts are forecasting that the CM market will increase to a market of 2 trillion Korean Won in 2015. Despite the superficial growth of market, according to a report of investigation, CM is at its naive stage yet in Korea. Therefore, it is significant to measure performance of CM projects, for growth of CM market in Korea, which were over and are come to an end shortly. The objective of this study is to measure performance of 29 sample CM projects that are selected from public construction projects in Korea. And this study shows a direction for domestic CM activation, based on analysis results of the performance measurement.

제주 해녀춤의 사회적 기능과 예술적 특성 연구

김은희(Eun Hui Kim),안병주(Byeong Ju Ahn) 한국사회체육학회 2011 한국사회체육학회지 Vol.0 No.43

Art called dance has formed a form called folk dance as mankind itself has racial characteristics of being adjusted to society according to being accumulated the historically living experience under the close relationship with realistic situation. Haenyeo(female diver) dance in Jeju Island was created by living itself, and has been performed out of the special bracket called Haenyeo in the middle of its life, and can be said to be folk dance peculiar to us, whose dancing goal is closely related to real life. In order for Haenyeo dance to be restored and recreated as modern folk dance, there will be necessity for examining social functions and artistic characteristics of dance, and for seeking for historical appropriateness in restoration and recreation of Haenyeo dance. Accordingly, this study aimed to closely examine social functions and artistic characteristics of Haenyeo dance in Jeju Island, and came to reach the following conclusions. First, the social functions in a traditional sense were indicated to be ritual function, community-based function, playing function, function of conflict solution and deity, and communication function. Second, the social functions in a modern sense include the function as festival, community-based function, function of performance art, and function of loving tradition and promoting local patriotism. Third, as for artistic characteristics, it shows social and cultural unicity in Jeju Island, thereby being dance in a realism-based form available for feeling the past and the present of female diver. Also, it was mixed with dance, song, theatrical element, and play, thereby having been characterized by dance movement with strong simplicity and repetition and by instrumental dance. Fourth, accompaniment music is expressing attractive and rich dance movement in line with folksy Jeju ballad of Jeju Island. Even clothes and dance implements are composed of the real image and form in female divers. A reason for necessity of continuously restoring and recreating Haenyeo dance today can be said to be accredited to these social functions and artistic characteristics.