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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Radiation Protection and Research
Journal Basic Information
Journal DOI :
Korean Association for Radiation Protection
Editor in Chief :
Volume & Issues
Volume 26, Issue 4 - Dec 2001
Volume 26, Issue 3 - Sep 2001
Volume 26, Issue 2 - Jun 2001
Volume 26, Issue 1 - Mar 2001
Selecting the target year
Corrections of Self-Absorption Effect Using the Monte Carlo Method in the Radioactivity Analysis of Environmental Samples
Seo, Bum-Kyoung ; Lee, Dae-Won ; Lee, Kil-Yong ; Yoon, Yoon-Yeol ; Yang, Tae-Keun ;
Journal of Radiation Protection and Research, volume 26, issue 2, 2001, Pages 51~58
In the low level radioactivity measurement, such as environmental radioactivity, there were used commonly cylindrical and Marinelli type beakers by means of measurement container. If there are differences in the matrix density or sample height between standard source and sample, it must be determined full energy peak efficiency considering self absorption effect. In this paper, we compared measured efficiency with calculated full energy peak efficiencies in the HPGe detector using the Monte Carlo method. For cylindrical container, we calculated the variation of the efficiency with sample height. Also, we calculated the variation of the detection efficiency with apparent density in the cylindrical and Marinelli container. It was seen that it need to be corrected for self absorption in the energy range of below 1000keV. Also, in order to verify the validity of calculation, we compared the calculated value with reference value using NIST SRM 4353 reference soil.
Determination of Tumor Boundaries on CT Images Using Unsupervised Clustering Algorithm
Lee, Kyung-Hoo ; Ji, Young-Hoon ; Lee, Dong-Han ; Yoo, Seoung-Yul ; Cho, Chul-Koo ; Kim, Mi-Sook ; Yoo, Hyung-Jun ; Kwon, Soo-Il ; Chun, Jun-Chul ;
Journal of Radiation Protection and Research, volume 26, issue 2, 2001, Pages 59~66
It is a hot issue to determine the spatial location and shape of tumor boundary in fractionated stereotactic radiotherapy (FSRT). We could get consecutive transaxial plane images from the phantom (paraffin) and 4 patients with brain tumor using helical computed tomography(HCT). K-means classification algorithm was adjusted to change raw data pixel value in CT images into classified average pixel value. The classified images consists of 5 regions that ate tumor region (TR), normal region (NR), combination region (CR), uncommitted region (UR) and artifact region (AR). The major concern was how to separate the normal region from tumor region in the combination area. Relative average deviation analysis was adjusted to alter average pixel values of 5 regions into 2 regions of normal and tumor region to define maximum point among average deviation pixel values. And then we drawn gross tumor volume (GTV) boundary by connecting maximum points in images using semi-automatic contour method by IDL(Interactive Data Language) program. The error limit of the ROI boundary in homogeneous phantom is estimated within
. In case of 4 patients, we could confirm that the tumor lesions described by physician and the lesions described automatically by the K-mean classification algorithm and relative average deviation analyses were similar. These methods can make uncertain boundary between normal and tumor region into clear boundary. Therefore it will be useful in the CT images-based treatment planning especially to use above procedure apply prescribed method when CT images intermittently fail to visualize tumor volume comparing to MRI images.
Design of Neutron Shielder for Reducing Background of Low Level Gamma Ray Spectrometer
Kim, Tae-Wook ; Park, Jong-Mook ; Park, Jong-Gil ; Shin, Sang-Woon ; Jun, Jae-Shik ;
Journal of Radiation Protection and Research, volume 26, issue 2, 2001, Pages 67~71
In order to shield the neutrons affecting the background of Low Level Gamma Ray Spectrometer, a neutron shielder was designed. The method used in this study for neutron shielding was the deceleration of fast neutrons by high density polyethylene(HDPE) and the absorption of those slowing-down neutrons by
. The calculation results of neutron Interaction in HDPE using Monte Carlo simulation code MCNP4B showed that the thermal-neutron flux was maximum at 10 cm thickness of HDPE. The results also showed that 95% of the thermal neutrons were absorbed by 2 mm thickness of
absorber Consisted of 30 w%
and 70 w% polymer. The results of the Monte Carlo calculation were in good agreement with the experimental value obtained by a neutron shielding apparatus designed for this purpose.
Determination of the exposure conversion coefficient for 3" X 3" NaI spectrum
Lee, M.S. ;
Journal of Radiation Protection and Research, volume 26, issue 2, 2001, Pages 73~78
In order to find the exposure conversion coefficients for 3"X3" NaI spectrum, we measured the exposure rates with the pressurized ion chamber at 29 different areas in the range of
, and also measured the gamma spectra with 3"X3" and 4"X4" NaI detectors, simultaneously. The exposure conversion coefficient of the total energy method was determined using the linear relation between the measured exposure rate and the gamma spectrum energy. In order to find the exposure conversion coefficients of the energy band method, we applied the exposure conversion coefficients recommended by NCRP to the 4"X4" NaI spectra, and calculated the exposure rates due to
series respectively. Using the linearly proportional relation between the obtained
series exposure rate and peak area of 2614 keV that represents the
series, we obtained the exposure conversion coefficients for
series. We also determined the conversion coefficients for
using a similar method.
Quantitative Exposure Assessment of Indoor Radon Released from Groundwater
Yu, Dong-Han ; Kim, Sang-Joon ;
Journal of Radiation Protection and Research, volume 26, issue 2, 2001, Pages 79~86
This study presents the quantitative exposure assessment of indoor radon released from groundwater. Most of the Indoor radon comes directly from soil beneath the basement or foundation. Recently, radon in groundwater releases to indoor air whenever the water is used and contributes to the total inhalation risk from indoor air. This study first develops a mathematical model to describe the transfer and distribution of radon released from groundwater in a house. Then, daily human exposures through inhalation or such radon are estimated with the model for an male adult based on two sets of exposure scenarios. The results obtained from the study would help increase the understanding of risk assessment issues associated with the indoor radon released from groundwater.
A Study on the Determination of Radionuclide Concentrations in Animal Feedstuffs for Use Following a Nuclear Emergency
Hwang, Won-Tae ; Kim, Eun-Han ; Suh, Kyung-Suk ; Choi, Young-Gil ; Han, Moon-Hee ;
Journal of Radiation Protection and Research, volume 26, issue 2, 2001, Pages 87~91
The optimized derived intervention levels for animal products were evaluated based on cost-benefit analysis. From these results, the radionuclide concentrations in animal feedstuffs for use were derived. It was shown that radionuclide concentrations in animal feedstuffs for use depend strongly on animal products, radionuclides and feeding period (period from the starting time to be led with contaminated feedstuffs to production time of animal products). In case of feedstuffs contaminated with long-lived radionuclides (
), the feedstuffs with lower contamination should be supplied to animals with increase of feeding period due to the bioaccumulation of radionuclides. While, in case of feedstuffs contaminated with short-lived radionuclides (
), the feeding of higher contaminated feedstuffs was possible with increase of feeding period due to radionuclide decay. It was shown that
concentration in animal feedstuffs lot use was lower than
concentration. It is primarily, due to the higher feed-animal product transfer factor of
Construction of voxel head phantom and application to BNCT dose calculation
Lee, Choon-Sik ; Lee, Choon-Ik ; Lee, Jai-Ki ;
Journal of Radiation Protection and Research, volume 26, issue 2, 2001, Pages 93~99
Voxel head phantom for overcoming the limitation of mathematical phantom in depleting anatomical details was constructed and example dose calculation for BNCT was performed. The repeated structure algorithm of the general purpose Monte Carlo code, MCNP4B was applied for yokel Monte Carlo calculation. Simple binary yokel phantom and combinatorial geometry phantom composed of two materials were constructed for validating the voxel Monte Carlo calculation system. The tomographic images of VHP man provided by NLM(National Library of Medicine) were segmented and indexed to construct yokel head phantom. Comparison of doses for broad parallel gamma and neutron beams in AP and PA directions showed decrease of brain dose due to the attenuation of neutron in eye balls in case of yokel head phantom. The spherical tumor volume with diameter, 5cm was defined in the center of brain for BNCT dose calculation in which accurate 3 dimensional dose calculation is essential. As a result of BNCT dose calculation for downward neutron beam of 10keV and 40keV, the tumor dose is about doubled when boron concentration ratio between the tumor to the normal tissue is
. This study established the voxel Monte Carlo calculation system and suggested the feasibility of precise dose calculation in therapeutic radiology.
Relationship between the DNA content of human chromosome and their contribution to radiation-induced chromosome aberration analysed by fluorescence in situ hybridization(FISH)
Chung, Hai-Won ; Kim, Su-Young ; Ha, Sung-Whan ; Kim, Tae-Hwan ; Cho, Chul-Koo ;
Journal of Radiation Protection and Research, volume 26, issue 2, 2001, Pages 101~111
To study the relationship between the DNA content of human chromosomes and their involvement in radiation-induced structural chromosome aberrations, the frequencies of translocations and dicentrics induced in human lymphocytes after in vitro exposure to 2Gy of x-tay were analysed by fluorescence in situ hybridization(FISH). Single whole chromosome probes(WCP), specific for chromosomes 1, 2, 4, 7, 8, 9, and 21 and triple combination of probes tot chromosome 1, 2 & 4 were used separately. A significant deviation of the frequency of symmetrical translocation and dicentrics from a DNA-proportional distribution was observed. Chromosomes 2, 7, 8, 9 and 21 were less frequently involved in the formation of symmetrical translocations and dicentrics than expected, whereas chromosomes 1 and 4 were more frequently involved. Chromosome 2 and 4 showed a higher frequency of acentric fragments. When triple combination probe for chromosome 1, 2 & 4 was used, no differences were found between the observed and expected frequency of exchange type aberrations. The results showed that the frequency of radiation-induced chromosome aberrations was not proportional to DNA contents, suggesting the difference in the susceptibility to specific aberrations among individual chromosomes. The results also indicated that the FISH technique with combination of probes for chromosome 1, 2 & 4 was useful for radiation biodosimetry.
Calculation of Man-made Radiation Exposure Rate from NaI Spectrum
Lee, M.S. ;
Journal of Radiation Protection and Research, volume 26, issue 2, 2001, Pages 113~117
The energy band method for NaI spectrum calculates only the exposure rate due to natural radiation because it calculates exposure rate using energy spectrum of
. However, the total energy method includes in its calculation the exposure rate due to man-made radiation because it uses the energy spectrum of
. Therefore, the resulting difference of extracting the exposure rate calculated by the energy band method from the exposure rate calculated by the total energy method is apparently the exposure rate due to man-made radiation. In this study, we measured the NaI spectrum during the period of significant changes of the exposure rate in the area without a man-made radiation. As the results, we found the exposure rates calculated by those two methods are equal within the statistical variation of
. Consequently, if the difference between the exposure rates calculated by the two methods exists, it may be due to the man-made radiation exposure rate.
Investigation of the Safety and Technical Criteria for HLW Disposal in Other Countries
Choi, Jong-Won ; Kwon, San-Gi ; Ko, Won-Il ; Kang, Chul-Hyung ;
Journal of Radiation Protection and Research, volume 26, issue 2, 2001, Pages 119~132
This paper provides the basic technical and safety criteria to guide establishing the reference HLW geological repository system that has been developing based on the recommendations from the international organizations such as IAEA and ICRP as well as the comparison of the regulations of several leading countries in HLW disposal. The proposed criteria and guidelines were categorized by the basic principles and general criteria for the radiological safety and the functional criteria of the repository system components. They would be useful for the development of the national regulations and criteria for HLW disposal in the future. They, of course, will be revised based on the deep geological investigation in Korean Peninsular which will be implemented in the future.