Recently Conformity Assessment Scheme has greatly played a role in development of domestic industry. But it has limits in responding to change of environment surrounding standard. Therefore management environment has been changed, standard has been more important, and new treaties as like WTO/TBT have been appeared. In these respects this research tries to analyze the policy trends of developed countries and problems of domestic institutions. And it tries to propose seven plans to progress Conformity Assessment Scheme including improvement of domestic standard system on the basis of analytical implications.

The need for structuring an organized and systematic industrial standardization system in which to administers all standards being managed by various executive branches of the govemment is more than ever becoming important. Also as the global market conti

With the chance of entering WTO, China is promoting the rebuilding of conformity assessment system in order to conform to WTO/TBT requirement and international conformity assessment system. Firstly, this research make it clear that the importance of conformity assessment activity, and the international movement of conformity assessment activity. Secondly, this paper surveyed the development course of conformity assessment activity and it's present operating system in China. Finally, this paper concludes the problems of present conformity assessment activity and implies the improving scheme. In the meantime, it also point out the later possible research topic in this field.

With the chance of entering WTO, China is promoting the rebuilding of conformity assessment system in order to conform to WTO/TBT requirement and international conformity assessment system. Firstly, this research make it clear that the importance of confo

Along with the enlargement of WTO, issues about standardization activity are more and more become concerning object worldwide. Countries launch the work that putting the standardization in order, such as re-establishing their standardization strategy. Wit

본 연구에서는 일반 촬영 검사 부위 중 조사 조건이 가장 높은 요추 검사에서, 최적의 조사 조건에 대하여 알아보고 자 하였다. 이를 위해 통계적으로 많이 이용하고 있는 조사 조건을 기준으로 선정하였고, 선량 변화 인자를 적용한 실 험군을 선정하였으며, 환자선량 권고량을 활용하여 임상에 적합한 실험군을 선별하였다. 블라인드 테스트는 전문의 및 방사선사 10명에 의해 수행되었고, 결과 최적화된 조사 조건에서, 전후 방향 검사의 경우 2.09 mGy, 측방향 검사의 경우 4.42 mGy, 사방향 검사의 경우 3.65 mGy 만큼의 선량 저감화가 가능할 것으로 사료된다. 차후에는 환자의 상태 에 따른 조사 조건의 최적화 연구가 수행되어야 할 것으로 사료된다.

본 연구는 고해상도 디지털 X선 영상 검출기 적용을 위해 미세 Gd2O2S:Tb 형광체 분말을 저온 액상법을 이용하여 합성하였다. 제조된 형광체 분말을 이용하여 입자침전법을 이용하여 형광체 필름을 제작하여 발광특성을 조사하였다. 측정결과, Tb 첨가농도에 따른 상대적인 발광량 측정결과 5 wt%의 첨가농도에서 가장 높은 발광효율을 보였으며, 첨 가농도가 증가할수록 소광현상에 의한 발광강도가 급격히 감소하는 경향을 보였다. 또한 270 ㎛ 두께의 Gd2O2S:Tb에 서 2945 pC/cm2/mR의 발광 강도를 가졌으며, 발광 강도가 거의 포화되는 것을 관찰할 수 있었다. 끝으로 제조된 형광 체의 영상획득 성능을 평가하기 위해 상용화된 CMOS 센서를 이용하여 X선 영상을 획득하여 MTF, NPS를 측정하여 DQE 평가를 수행하였다. 측정결과, DQE(0)의 값은 37%로 다소 낮은 값을 보였다. 향후 필름 제조 공정상의 문제점 을 해결한다면, DQE를 개선할 수 있을 것으며, 고해상도 의료 방사선 영상 시스템 적용에 유용하게 적용 가능할 것으 로 판단된다.

In this study, the basic research verifying possibility of applications as radiology image sensor in Digital Radiography was performed, the radiology image sensor was fabricated using double layer technique tio decrease dark current. High efficiency material in substitution for a-Se have been studied as a direct method of imaging detector in Digital Radiography to decrease dark current by using Hetero junction already used as solar cell, semiconductor. Particle-In-Binder method is used to fabricate radiology image sensor because it has a lot of advantages such as fabrication convenient, high yield, suitability for large area sensor. But high leakage current is one of main problem in PIB method. To make up for the weak points, double layer technique is used, and it is considered that high efficient digital radiation sensor can be fabricated with easy and convenient process. In this study, electrical properties such as leakage current, sensitivity is measured to evaluate double layer radiation sensor material.