• Proceedings of the KSME Conference
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• 2001.06c
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• pp.207-212
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• 2001

The virtual reality technology has been developed as the computer and computer graphic technology are progressed. However it has still the limits of the use because of it costs a great for system construction. A virtual reality technology is the best application example to reduce time and cost of development in engineering. Actually, VR(Virtual reality) technology has given engineers the ability to design, test and evaluate engineering systems in a virtual environment. The objective of this paper is to construct the arm mounted display VR system by using 3 channel spherical screen and to show its capabilities of an engineering system development. This paper describes the development of arm mounted display VR system with 3 channel spherical screen system and the generation of 3 channel graphic modules. The arm mounted display VR system provides a highly economical efficiency because of it uses a popular computer system as a graphic server.

• The Korean Journal of Nuclear Medicine
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• v.34 no.1
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• pp.82-93
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• 2000

Purpose: We characterized the signals obtained from the components of a small gamma camera using Nal(Tl)-position sensitive photomultiplier tube (PSPMT) and optimized the parameters employed in the modules of the system. Materials and Methods: The small gamma camera system consists of a Nal(Tl) crystal ($60{\times}60{\times}6mm^3$) coupled with a Hamamatsu R3941 PSPMT, a resister chain circuit, preamplifiers, nuclear instrument modules (NIMs), an analog to digital converter and a personal computer for control and display. The PSPMT was read out using a resistive charge division circuit which multiplexes the 34 cross wire anode channels into 4 signals (X+, X-, Y+, Y -). Those signals were individually amplified by four preamplifiers and then, shaped and amplified by amplifiers. The signals were discriminated and digitized via triggering signal and used to localize the position of an event by applying the Anger logic. The gamma camera control and image display was performed by a program implemented using a graphic software. Results: The characteristics of signal and the parameters employed in each module of the system were presented. The intrinsic sensitivity of the system was approximately $8{\times}10^3$ counts/sec/${\mu}Ci$. The intrinsic energy resolution of the system was 18% FWHM at 140 keV. The spatial resolution obtained using a line-slit mask and $^{99m}Tc$ point source were, respectively, 2.2 and 2.3 mm FWHM in X and Y directions. Breast phantom containing $2{\sim}7mm$ diameter spheres was successfully imaged with a parallel hole collimator. The image displayed accurate size and activity distribution over the imaging field of view Conclusion: We proposed a simple method for development of a small gamma camera and presented the characteristics of the signals from the system and the optimized parameters used in the modules of the small gamma camera.