• Journal of the Korean Society of Safety
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• v.24 no.2
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• pp.100-104
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• 2009

In this study, the space gamma dose rates in the apartments structured with concrete were measured in accordance with construction year. In addition, the environmental radiation rates coming from the subway platforms and the road tunnels were analyzed in the equivalent dose by multiplying the absorbed dose with the radiation weighting factors. The space gamma dose rates measured in apartments were higher than those of outdoor which was $0.08{\sim}0.11uSv/h$ in the natural conditions. Especially, the older construction year is, the higher becomes space gamma dose rate. The average gamma dose rates in the subway platforms were measured. In the case of Busan and Daegu subway, the earlier the opening year is, the higher becomes dose rate. However, the dose rates of Seoul subway Lines were high overall, regardless of opening year. Seoul subway Line 6 showed the highest value of 0.21uSv/h. The gamma dose rate in road tunnels was higher than one of the outdoor and increased with opening year like as apartment. In dose rate comparison of the concrete structures with the outdoor, therefore, the space gamma dose rate of indoor is higher than one of the outdoor and the older structures have a higher dose rate.

• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.289-294
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• 2020

In order to control the quality of X-ray images and patient exposure, it is necessary to document the output dose(air absorption dose(mGy)) output from the X-ray unit from the measurement. The purpose of this study is to find an equation that can calculate the output dose from the measurement of the output dose and output factor(Of) of the X-ray Unit. The output dose and output factors of the X-beam irradiated from the X-ray unit were measured using an XR multi-detector. The output dose calculation formula was obtained by fitting the measured output dose divided by the tube current-exposure time product(mAs) and the set tube voltage with Allometric1. The final output dose calculation formula was obtained by multiplying this formula with the output factor. It is considered that the obtained final output dose calculation formula will be useful for all tube voltages, tube currents, exposure times, field sizes, and distances.

• Korean Journal of Food Science and Technology
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• v.21 no.2
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• pp.185-191
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• 1989

The combined effects of heat treatment and ${\gamma}-irradiation$ on the inactivation of major lactic acid bacteria associated with Kimchi fermentation were investigated. The radiosensitivities $(D_{10}\;values)$ of lactic acid bacteria in case of a single treatment of irradiation were 0.61 kGy in Lactobacillus brevis, 0.60 kGy in Lactobacillus plantarum, 0.50 kGy in Leuconostoc mesenteroides, 0.4 kGy in Pediococcus cerevisiae, 0.39 kGy in Streptococcus faecalis. The heat sensitization $(D_{min}\;values)$ by a single treatment of heat ranged 9.2-15.6 at $50^{\circ}C$ and 3.7-5.5 at $60^{\circ}C$. Synegistic effects were shown in the radiosensitivities of Streptococcus faecalis, Pediococcus cerevisiae, Lactobacillus plantarum, and Lactobacillus brevis by the combined treatment(Dose multiplying factors ranged $1.20{\sim}1.56$). It seems, therefore, that the combined treatment can be applied to the radiation preservation of Kimchi, minimizing the side-effects like physical changes induced by the high dose irradiation or heat treatment.

• Progress in Medical Physics
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• v.23 no.4
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• pp.303-308
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• 2012

The Geant4 based Monte Carlo code for the application of stereotactic radiosurgery was developed. The probability density function and cumulative density function to determine the incident photon energy were calculated from pre-calculated energy spectrum for the linac by multiplying the weighting factors corresponding to the energy bins. The messenger class to transfer the various MLC fields generated by the planning system was used. The rotation matrix of rotateX and rotateY were used for simulating gantry and table rotation respectively. We construct accelerator world and phantom world in the main world coordinate to rotate accelerator and phantom world independently. We used dicomHandler class object to convert from the dicom binary file to the text file which contains the matrix number, pixel size, pixel's HU, bit size, padding value and high bits order. We reconstruct this class object to work fine. We also reconstruct the PrimaryGeneratorAction class to speed up the calculation time. because of the huge calculation time we discard search process of the ThitsMap and used direct access method from the first to the last element to produce the result files.

• Journal of radiological science and technology
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• v.28 no.4
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• pp.293-299
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• 2005

In the present investigation, we analyzed the data of 1,318 patients (2,636 images) who underwent mammographic examinations and obtained the distribution of the patient age and compressed breast thickness. We measured also average glandular doses (AGD) as function of compressed breast thickness. In order to obtain the values of AGD, we measured half value layer (HVL) and tube output (mR/mAs) for each kVp and target/filter combination. Entrance surface air kerma (ESAK) was calculated from the tube output as measured for each voltage used under clinical conditions and from the tube loading (mAs). AGD per exposure were calculated by multiplying the ESAK values by the conversion factors tabulated by Dance. We obtained in this study the following conclusions. The mean value of compressed breast thickness for cranio-caudal (CC) view was 35.8mm and that for medio-lateral oblique (MLO) view was 43.3 mm. The mean value of AGD for CC view was 1.55 mGy and that for MLO view was 1.70 mGy. The AGD for MLO view was 0.15 mGy (10%) higher than that for CC view because the thickness for MLO view was on average 4.8 mm higher than that for CC view. The values of AGD increased with increasing compressed brest thickness. The increased AGD value was on average 0.34 mGy per 10 mm in the thickness ranges $10{\sim}80\;mm$, therefore differences between the AGD values of each thickness were relative large. Thus, it is considered to need limited doses for mammography with the upper end of exposure range at several different compressed brest thickness.