The purpose of this study was to measure the radiation exposure to operator and patient during cardiac electrophysiology study, radiofrequency catheter ablation and cardiac device implantation procedures and to calculate the allowable number of cases per year. We carried out 9 electrophysiology studies, 40 radiofrequency catheter ablation and 11 cardiac device implantation procedures. To measure occupational radiation dose and dose–area product (DAP), 13 photoluminescence glass dosimeters were placed at eyes (inside and outside lead glass), thyroids (inside and outside thyroid collar), chest (inside and outside lead apron), wrists, genital of the operator (inside lead apron), and 6 of photoluminescence glass dosimeters were placed at eyes, thyroids, chest and genital of the patient. Exposure time and DAP values were 11.7 ± 11.8 min and 23.2 ± 26.2 Gy cm2 for electrophysiology study; 36.5 ± 42.1 min and 822.4 ± 125.5 Gy cm2 for radiofrequency catheter ablation; 16.2 ± 9.3 min and 27.8 ± 16.5 Gy cm2 for cardiac device implantation procedure, prospectively. 4591 electrophysiology studies can be conducted within the occupational exposure limit for the eyes (150 mSv), and 658-electrophysiology studies with radiofrequency catheter ablation can be carried out within the occupational exposure limit for the hands (500 mSv). 1654 cardiac device implantation procedure can be conducted within the occupational exposure limit for the eyes (150 mSv). The amounts of the operator and patient's radiation exposure were comparatively small. So, electrophysiology study, radio frequency catheter ablation and cardiac device implantation procedures are safe when performed with modern equipment and optimized protective radiation protect equipment.
Oxygen vacancy clustering in SrTiO 3-δ thin films has been investigated by electrical transport and photoemission spectroscopy. We deposited SrTiO 3-δ thin films on LaAlO3(001) substrate at reducing oxygen ambients. The carrier density did not increase with decreasing the ambient oxygen pressure. Photoemission study shows multi valence state of Ti ion including Ti +2 which localized state. Those results are explained by electron localization via oxygen vacancy clustering.
Recently, risk management in product development processes has been regarded as an important issue in many manufacturers. Although many different approaches have been suggested to deal with various risks frequently occurred in business level such as cost related fields, there have been few studies for managing various risks in plant level. This paper suggests a new risk management framework (RMF) for managing risks in product development processes. The RMF presents risk factors along with their degrees and shows the proper activities to respond to those risks on the basis of operations, processes and departments under concurrent engineering environment. Also, this framework adapts a network model to determine the optimized paths for establish a successful product development process. In this paper, we focus on the structure or architecture defending systematically various risks.
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