• 대한방사선기술학회지:방사선기술과학
• /
• 제35권4호
• /
• pp.309-314
• /
• 2012

Digital Radiography(DR) 시스템은 임상현장에서 아날로그 시스템을 대체하고 널리 이용되고 있다. DR을 이용하여 얻어진 X선 영상의 해상력을 결정짓는 요소에는 이용되는 검출기의 고유 해상력, 피사체의 대조도 및 특성, X선 선질, X선원의 산란, DR 검출기의 성능, X선 변환효율 및 초점의 크기, 피사체의 움직임 등이 있다. DR 검출기를 구성하는 요소에는 X선 포획 요소, 커플링 요소, 정보수집 요소가 있는데 이들은 시스템의 성능에 영향을 미치며, 그 성능은 해상력으로 평가된다. 의료영상 시스템의 해상력은 촬영대상물의 조직 간의 해부학적 영상을 구분하는 능력을 나타낸다. 해상력 평가를 위해 Modulation Transfer Function(MTF)이 보편적으로 이용되고, MTF는 입력 공간주파수 성분에 대한 출력 공간주파수 성분의 비를 나타내는데, 수학적으로 MTF는 Point Spread Function(PSF) 입력에 대한 시스템의 주파수 응답이며 Edge Phantom을 이용한 결과 영상에서 추출된 Line Spread Function(LSF)을 Fourier Transform하면 얻을 수 있다. 일반적으로 임상현장에서 의료영상시스템의 이용 및 관리의 책임은 방사선사가 맡고 있지만, MTF를 측정하기 위해서는 공학적, 수학적 기초 및 C, Fortran, Matlab등의 프로그램 작성 능력이 필요하기 때문에 비 공학도는 정확한 측정이 불가능하다. 의료영상 시스템의 성능 관리 및 최상의 상태를 유지하기 위해 시스템의 성능평가가 이뤄져야 하는데, 이를 위해 본 연구에서는 비공학도가 해상력 성능평가를 할수 있도록 ImageJ 및 Excel을 이용하여 해상력 평가를 할 수 있도록 방법을 제시하고, 제안된 방법을 이용해 계산된 결과와 프로그래밍을 이용해 계산된 결과의 비교를 통해 본 논문에서 제시하는 방법의 유용성을 확인하였다.

• 대한핵의학회지
• /
• 제26권2호
• /
• pp.265-273
• /
• 1992

Rest gated blood pool scan (Rest GBP scan) and dipyridamole $^{99m}Tc-MIBI$ SPECT were Performed in 34 patients with or suspected coronary artery disease. Both studies were performed within $2\sim32$ days (mean 8.1 days). A significant correlation was present between left ventricular ejection fraction (r= -0.7356, p<0.001) and peak ejection rate and peak filling rate in rest GBP scan and perfusion defect in MIBI SPECT. And there were acceptable correlations (0.05$26.2{\pm}10.8%$, severe hypokinesia, akinesia or dyskinesia in 16 regions: $78.2{\pm}23.7$, p<0.001). These data indicate there is a significant coupling between the degree of myocardial perfusion and the myocardial functional change in coronary artery disease.

• Journal of Information Technology Applications and Management
• /
• 제28권3호
• /
• pp.59-75
• /
• 2021

This study aims to establish a foundation for autonomous driving on campus and communication of abundant university information in the HCI environment in a VR environment where college freshmen can freely travel around campus facilities. The purpose of this study is to develop a three-dimensional VR-style campus tour system to establish a media environment to provide abundant university information guidance services to freshmen in non-face-to-face situations. This study designed a three-dimensional virtual reality campus tour system to solve the problem of discontinuity in which VR360 filming space does not lead to space like reality, and to solve many problems of expertise in VR technology by constructing an integrated production environment of tour system. We aim to solve the problem of inefficiency, which requires a large amount of momentum in virtual space, by constructing a GUI that utilizes the motion of the field of view focus. The campus environment was designed as a three-dimensional virtual reality using a three-dimensional graphic design. In non-face-to-face situations, college freshmen freely transformed the HMD VR device, smartphone, FPS operation mode of the gyroscope sensor. The design elements of the three-dimensional virtual reality campus tour system were classified as ①Visualization of factual experiences, ②Continuity of space movement, ③Operation, automatic operation mode, ④Natural landscape animation, ⑤Animation according to wind direction, ⑥Actual space movement mode, ⑦Informatization of spatial understanding, ⑧GUI by experience environment, ⑨Text GUI by building, ⑩VR360, 3D360 Studio Environment, ⑪Three-dimensional virtual space coupling block module, ⑫3D360-3D Virtual Space Transmedia Zone, ⑬Transformable GUI(VR Device Dual Viewer-Gyro Sensor Full Viewer-FPS Operation Viewer) and an integrated production environment was established with each element. It is launched online (http://vautu.com/u1) by constructing a GUI for free driving mode and college information screens to adapt to college life for freshmen, and designing an environment that can be used simultaneously by current media such as PCs, Android, and iPads. Therefore, it conducted user research, held a development presentation, a forum on excellence in university innovation support projects, and applied it as a system on the website of a particular university. College freshmen will be able to experience university information directly from the web and app to the virtual reality campus environment.