• 대한방사선방어학회:학술대회논문집
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• 2011.11a
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• pp.208-209
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• 2011

• Journal of radiological science and technology
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• v.42 no.6
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• pp.455-460
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• 2019

This study compared the radiation transmission and image quality of polymethylmethacrylate (PMMA), polycarbonate (PC), and carbon, which are common components of the compression plates currently used during breast imaging. In addition to measuring the transmitted dose and the intensity without the use of a compression paddle, the four different compression paddles were evaluated according to the material and thickness of each paddle. Radiation transmittance, maximum intensity, and plot profile type w ere all evaluated for each material, and for each factor evaluated the follow ing order w as noted, from best to w orst: carbon 4 mm, PMMA 3 mm, PMMA 4 mm, and PC 4 mm. It is necessary to study a variety of materials and thicknesses in order to find the optimal combination of material and thickness, because not only does the material have a large influence in reducing the radiation exposure during mammography, but the thickness of the compression plate also has a great influence.

• Journal of radiological science and technology
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• v.41 no.5
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• pp.457-462
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• 2018

The purpose of this study was to compare image quality of indirect digital radiography (IDR) system using the International Electro-technical Commission standard (IEC 62220-1), and to suggest the analysis of noise power spectrum (NPS) which were applied to IEC 62220-1 in medical imaging. In this study, Pixium 4600 (Trixell, France) which is indirect flat panel detector (FPD) was used. The size of image receptor (IR) is $7{\times}17$ inch (matrix $3001{\times}3001$) which performed 14bit processing and pixel pitch is $143{\mu}m$. In IEC standard, NPS evaluation were applied to RQA3, RQA5, RQA7 and RQA9. Because of different radiation quality, each region of interesting (ROI) were compared. The results of NPS indicated up to $3.5mm^{-1}$ including low Nyquist frequency. RQA5 indicated the lowest NPS and the others indicated higher NPS results relatively. NPS result of ROI a38 was higher than ROI a92 and this result indicated that there are more noise in left (cathode) than right (anode). This study were to evaluate NPS by using different radiation quality and setting the each ROI, and to suggest the quantitative methods of measuring NPS.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.237-240
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• 2002

Knowing the dose distribution in a tissue is as important as being able to measure exposure or absorbed dose in radiotherapy. Since the Dry Imager spread, the wet type automatic processor is no longer used. Furthermore, the waste fluid after film development process brings about a serious problem for prevention of pollution. Therefore, we have developed a measurement method for the dose distribution (CR dosimetry) in the phantom based on the imaging plate (IP) of the computed radiography (CR). The IP was applied for the dose measurement as a dosimeter instead of the film used for film dosimetry. The data from the irradiated IP were processed by a personal computer with 10 bits and were depicted as absorbed dose distributions in the phantom. The image of the dose distribution was obtained from the CR system using the DICOM form. The CR dosimetry is an application of CR system currently employed in medical examinations to dosimetry in radiotherapy. A dose distribution can be easily shown by the Dose Distribution Depiction System we developed this time. Moreover, the measurement method is simpler and a result is obtained more quickly compared with film dosimetry.

• Progress in Medical Physics
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• v.31 no.2
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• pp.20-28
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• 2020

Purpose: The objective of this study is to perform Postal dosimetry audits for medical linear accelerators in radiation therapy institutions using glass dosimeters and Gafchromic film reading systems and postal dosimetry audit procedures, and to evaluate radiation therapy doses and mechanical accuracy in medical institutions. Methods: Photon output measured and analyzed using a standard phantom for measuring photon output dose using a glass dosimeter for medical linear accelerators. Mechanical accuracy was measured and analyzed using software for film measurement. Results: Measurement and analysis of photon beam output dose using a standard phantom glass dosimeter for photon beam output dose measurement was completed. All tolerance doses were within 5%. Mechanical accuracy measurement and analysis using a standard phantom for verifying the mechanical accuracy of linear accelerator (LINAC) using a Gafchromic film were completed, and all results were shown within tolerances (2 mm or less). Conclusions: In this study, Postal dosimetry audits were performed on the output dose and mechanical accuracy of photon beams (207 beams) for 106 LINACs from 48 institutions. As a result of corrective action and re-execution, it was confirmed that all engines met the acceptable standard within 2 mm in the linear accelerator.

• Journal of Radiation Protection and Research
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• v.32 no.4
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• pp.134-139
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• 2007

In order to find out the Radioprotective effect of algin-oligosaccharide(AOS), this study, with a mouse of which whole frame irradiated by 3 Gy radiation once, measured caspase-3 and caspase-9 amid cell signaling connected to apoptosis in order to observe cell activation. In Caspase-3 and Caspase-9 test for observing cell activation, both of Caspase-3 and Caspase-9 showed highly increased O.D. value in the irradiation control group, while the whole groups treated with algin-oligosaccharide before or after irradiation indicated lower O.D. value than the irradiation control group, especially showed big difference in 7 day's treatment group of before irradiation (P<0.001). It confirmed that Caspase generation was restrained in AOS treatment group. Consequently, this study inquired into the fact that algin-oligosaccharide with superior antioxidant activity performed radiation protection by inducing restraint of Caspase generation and confirmed that natural product with less chemical toxicity was able to be applied as radioprotector.

• Journal of radiological science and technology
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• v.41 no.5
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• pp.445-450
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• 2018

We aim to evaluate safety of radiation by measuring leakage dose and patient(phantom) incident dose of ZEN-PX II dental portable equipment developed by G company. Measurement for leakage dose of equipment is conducted on the top, at the bottom, on the left, on the right and at the back. Dose measurement incident on the subject with the area dosimeter when using the phantom and measurement the leakage dose of equipment when using the phantom are evaluated. Comparing the right with the highest leakage dose as a 0 cm, 25 cm, 50 cm, 75 cm and 100 cm dose measurement at the measurement height of 100 cm, 64.2 uR was reduced to 47.3 uR in the senser mode 0.32sec. Even in film mode it was measured at 414.4 uR and about 27% lower at 162.6 uR. As the result of this study, when the irradiation time is 2 sec the right side dose is 290.5 uR and sensor mode is 0.32 sec the right side dose is 64.2 uR.

• Journal of radiological science and technology
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• v.43 no.1
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• pp.15-21
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• 2020

This study was purpose to evaluation of Modulation Transfer Function in Measurements by using the International electrotechnical commission standard(IEC 62220-1) which were edge device each angle by using edge method. In this study was Aero(Konica, Japan) image receptor which is a indirect Flat panel detector(FPD) was used. The size of matrix 1994 × 2430 (14"× 17" inch) which performed 12 bit processing and pixel pitch is 175 ㎛. The results of shown as MTF measurements at IEC standard. The amount of data seemed reasonable and at an MTF value of 0.1 the spatial frequencies were 2.56 cycles/mm at an angle of 2.4°. MTF value of 0.5 the spatial frequencies were 1.32 cycles/mm at an angle of 2.4°. This study were to evaluate MTF by setting each angle 2.0°~2.8° degrees the most effective optimal edge angle and to suggest the quantitative methods of measuring by using IEC.

• Progress in Medical Physics
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• v.24 no.3
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• pp.140-144
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• 2013

In this research, the glass dosimeter was calibrated to measure the standard absorbed dose of the Cs-137 irradiator and absorbed dose in a biological sample. Absorbed dose in water for Cs-137 gamma ray was determined by the IAEA TRS-277 protocol. The PTW-TM30013 ion chamber and the PTW-TM41023 water phantom were utilized for measuring absorbed dose and the value was compared with the reading from DoseAce GD-302M glass dosimeter from Asahi Techno Glass Corporation for its calibration. The uncertainty of measurement ($1{\sigma}$) of the calibrated glass dosimeter was 2.7% and this result would be applied to improve the accuracy in measurement of absorbed dose in a biological sample.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.2
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• pp.171-178
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• 2014

After the expiration of operating license of a plant, all infrastructures within the plant must be safely dismantled to the point that it no longer requires measures for radiation protection. Despite the fact that Kori 1 and Wolsong 1 are close to the expiration of their operating license, sufficient technologies for radiological characterization, decontamination and dismantling is still under development. The purpose of this study is to develop one of methods for radiological inventory assessment on measuring object by using direct measure of large component with In-Situ measurement technique. Radiological inventory was assessed by analyzing nuclide using portable gamma spectroscopy without dismantling reactor head, and the result of direct measurement was supplemented by performing indirect measurement. Radiochemical analysis were performed on surface contamination samples as well. During the study, radiological inventory of reactor vessel calculated expanding the result. Based on the result and the radioactivity variation of each radionuclides time frame for decommissioning can be decided. Thus, it is expected that during the decommissioning of plants, the result of this study will contribute to the reduction of radiation exposure to workers.