• Restorative Dentistry and Endodontics
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• v.10 no.1
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• pp.71-83
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• 1984

The purpose of this study was to evaluate the transmission spectrum of the set calcium hydroxide dental cement (Dycal, L.D. Caulk Co. Milford, Del.) Cement was prepared for A T R spectra at a low powder-to-liquid ratio of 3.0gm/ml in order to retard the reaction and facilitate the manipulation of loading the cement into the cell. Spectra were recorded on an I R Spectrophotometer (MX-1, FT) at an agle of incidence of 55. The A T R cell was a RIIc Model TR5 with a hemisperical KRS-5 (Thallium-Bromide-Iodide). A spectrum was recorded within 3 minutes. Further spectra were recorded after 5,10,30 minutes and 1,5,24, 72 hours. The results were as follows; 1. The setting reaction between acid paste and base past would take place fastly within 10 minutes after mix, and that would be slow until 72 hours after mix. 2. In the set cements, some methyl salicylate and calcium hydroxide remained unreacted until 72 hours after mix. 3. The setting reaction and the reaction rate occuring at the surface and in the bulk cements were similar. 4. The chelates were bound together between calcium hydroxide and methyl salicylate.

• Journal of the Korean Society of Radiology
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• v.16 no.5
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• pp.513-518
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• 2022

Electron beam quality assurance (QA) should be done regularly for accurate radiation therapy. However, QA tools used in clinical practice are designed mainly for X-rays. So, a dosimeter for electron beam QA is required. Therefore, in this study, the electron beam detection performance was measured by using a thorium bromide material as an electron beam sensor. In addition, it was evaluated whether it could be applied with an electron beam QA dosimeter. Reproducibility, linearity, and dose rate dependence were evaluated at 6 MeV and 9 MeV energies. As a result of reproducibility, it showed a maximum output change of 0.92% at 6 MeV and 1.15% at 9 MeV. The linearity result evaluation and determination coefficient were presented as 0.9998. As a result of dose rate dependence evaluation, relative standard deviation 0.51% at 6 MeV and relative standard deviation 1.07% at 9 MeV were presented. The manufactured TlBr sensor shows the ability to detect radiation that meets the criteria for evaluation of reproducibility, linearity, and dose rate dependence. These results mean that the TlBr dosimeter is applicable as an electron beam QA dosimeter.