• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.491-496
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• 2003

In Korea, the dose limits to the public were reduced according to ICRP-60 recommendations. The secondary quantities, Effluent Concentration Limits (ECLs) were derived and enacted to Korean Atomic Laws based on ICRP-60 recommendations. The Korea atomic laws require assurance that radioactive materials within gaseous effluents do not exceed dose limits and ECLs. This simply means that any effluent that would possibly contain radioactivity must be monitored. There are various methods to monitor the radioactivity of effluent monitor to satisfy the dose limits and the ECLs for gaseous effluents. The many factors (safety margin) should be considered in determining of the setpoint of effluent monitor, following these limits. In this study, we studied the determination method of alarm setpoint for gaseous effluent Radiation Monitoring Systems using dose factors considered the main pathway of radionuclides to compare the preceding determination method of alarm setpoint for gaseous effluent RMSs using dose assessment program considered all the practicable pathways of radionuclides.

• Journal of the Korean Society of Radiology
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• v.16 no.6
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• pp.719-725
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• 2022

This study aimed to measure, quantitatively evaluate, and set the criteria for the minimum lead(Pb) shield thickness per level of clinically applied electron beam energy. The lead shield thickness per electron beam energy was measured using the primary field 95% reduction based on the open field at the depth of maximum dose (d_max) and depth from the surface as the reference depth of tissue dose(10 mm). The measured values were 1.906 mmPb and 1.992 mmPb at the d_max and 10 mm, respectively, regarding the lead shield thickness for 6 MeV electron beam; 2.746 mmPb and 3.743 mmPb for 9 MeV electron beam, 3.718 mmPb and 6.093 mmPb for 12 MeV electron beam, 7.300 mmPb and 15.270 mmPb for 16 MeV electron beam, and 16.825 mmPb and 25.090 mmPb for 20 MeV electron beam. Consequently, a thicker lead shield was required if the measurement was at 10 mm. The required lead shield thickness was also higher than that of the theoretical formula for electron beams of ≥ 16 MeV.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.187-188
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• 2011

저 에너지 방사선검사 시 부득이하게 방사선 노출을 받게 되는 방사선 작업종사자나 환자의 보호자가 위치와 거리에 따른 방사선 피폭 선량의 감소 방안을 알아보고자 한다. Ion chamber mode 2026c, Reader기 20X6-1800을 사용하여 구강내 검사와 구강외 검사의 각각 검사실과 조정실에서의 관전압의 변화, 관전류와 조사시간의 변화, 조사방향의 변화에 따라 선량을 측정하였다. 그 결과 검사실 안에서는 최고선량이 평균 $702.8{\mu}R$으로 측정 되었으며, 조정실 안에서 측정하였을 경우 $20{\mu}R$이하의 낮은 선량을 보였으며, 후방검사보다 측방검사가 낮은 선량으로 나타났다. 방사선검사 시 위치와 거리에 따른 조사선량을 비교 분석하여, 적절한 거리 확보와 조사되는 중심방사선을 기준으로 측방($90{\sim}135^{\circ}$)에 위치함으로써 방사선 방어에 도움을 줄 것이며, 차폐문을 이용하여 방사선 피폭으로부터 감소 효과를 볼 수 있을 것이다.

• Radiation Oncology Journal
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• v.23 no.3
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• pp.176-185
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• 2005

Purpose: Film dosimetry as a part of patient specific intensity modulated radiation therapy quality assurance (IMRT QA) was peformed to develop a new optimization method of film isocenter offset and to then suggest new quantitative criteria for film dosimetry. Materials and Methods: Film dosimetry was peformed on 14 IMRT patients with head and neck cancers. An optimization method for obtaining the local minimum was developed to adjust for the error in the film isocenter offset, which is the largest part of the systemic errors. Results: The adjust value of the film isocenter offset under optimization was 1 mm in 12 patients, while only two patients showed 2 mm translation. The means of absolute average dose difference before and after optimization were 2.36 and $1.56\%$, respectively, and the mean ratios over a $5\%$ tolerance were 9.67 and $2.88\%$. After optimization, the differences in the dose decreased dramatically. A low dose range cutoff (L-Cutoff) has been suggested for clinical application. New quantitative criteria of a ratio of over a $5\%$, but less than $10\%$ tolerance, and for an absolute average dose difference less than $3\%$ have been suggested for the verification of film dosimetry. Conclusion: The new optimization method was effective in adjusting for the film dosimetry error, and the newly quantitative criteria suggested in this research are believed to be sufficiently accurate and clinically useful.

• Journal of radiological science and technology
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• v.40 no.3
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• pp.393-400
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• 2017

The purpose of this study is to suggest a method to reduce the dose by Analyzing the dose area product (DAP) and image quality according to the change of tube current using NEMA Phantom. The spatial resolution and low contrast resolution were used as evaluation criteria in addition to signal to noise ratio (SNR) and contrast to noise ratio (CNR), which are important image quality parameters of intervention. Tube voltage was fixed at 80 kVp and the amount of tube current was changed to 20, 30, 40, and 50 mAs, and the dose area product and image quality were compared and analyzed. As a result, the dose area product increased from $1066mGycm^2$ to $6160mGycm^2$ to 6 times as the condition increased, while the spatial resolution and low contrast resolution were higher than 20 mAs and 30 mAs, Spatial resolution and low contrast resolution were observed below the evaluation criteria. In addition, the SNR and CNR increased up to 30 mAs, slightly increased at 40 mAs, but not significantly different from the previous one, and decreased at 50 mAs. As a result, the exposure dose significantly increased due to overexposure of the test conditions and the image quality deteriorated in all areas of spatial resolution, low contrast resolution, SNR and CNR.

• Journal of Radiation Protection and Research
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• v.39 no.4
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• pp.159-167
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• 2014

In Korea, July 2012, the law as called 'Act on Safety Control of Radioactive Rays Around Living Environment' was implemented to control the consumer product containing Naturally Occurring Radioactive Material (NORM), but, there are no appropriate database and effective dose calculation system. The aim of this study was to develop evaluation technique of the exposure dose with the use of the consumer products containing NORM and to understand the characteristics of the exposed dose according to the radiation type and energy. For the evaluate of exposure dose, the ICRP reference phantom was simulated by the MCNPX code based on Monte Carlo method, and the minimum, medium, maximum energy of alphas, betas, gammas from the representative NORM of Uranium decay series were used as the source term in the simulation. The annual effective doses were calculated by the exposure scenario of the consumer product usage time and position. Short range of the alpha and beta rays are mostly delivered the dose to the skin. On the other hand, the gamma rays mostly delivered the similar dose to all of the organs. The results of the annual effective dose with $1Bq{\cdot}g^{-1}$ radioactive stone-bed and 10% radioactive concentration were employed with the usage time of 7 hours 50 minute per day, the maximum annual effective dose of alphas, betas, gammas were calculated 0.0222, 0.0836, $0.0101mSv{\cdot}y^{-1}$, respectively.

• Journal of Radiation Protection and Research
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• v.21 no.4
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• pp.255-262
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• 1996

This paper describes the results of intercomparison measurements of KAERI reference photon and beta radiation fields between the KAERI and the PNNL(Pacific Northwest National Laboratory), recently performed at KAERI radiation calibration and dosimetry laboratory on the basis of the ANSI N13.11 criteria for personal dosimeter performance test. Each laboratory used her own radiation detectors or measurement devices traceable to her national primary standard in measuring the exposure rates for photon fields, the absorbed dose rates for beta radiation fields. The agreements in reference radiation measurements between two laboratories were found to be less than ${\pm}2.0%$ for photon fields, ${\pm}1.0%$ for beta radiation fields. Therefore, it could be concluded that KAERI reference radiation fields comply well with the international standard and thus can further serve as a national basis for the researches and developments in radiation protection dosimetry in Korea.

• Journal of Radiation Protection and Research
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• v.17 no.2
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• pp.1-13
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• 1992

The purpose of this study is to develop an algorithm of TLD dose evaluation to meet all requirements stated in ANSI N13. 11-1983. It made the PB-3 TLD of Teledyne Isotopes an object of the development. Personal dosimetry performance testings of the development algorithm have been performed twice through the Atlan-Tech, INC. in accordance with the criteria of testing described in ANSI N13. 11-1983. As ,a result, it is assured that the developed algorithm has complied with all requirements stated in ANSI N13. 11-1983.

• Journal of the Korea Convergence Society
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• v.8 no.8
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• pp.147-154
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• 2017

The purpose of this study is to calculate and compare administered activities(MBq) and effective dose(mSv) of the various pediatric dose formulas of pediatric nuclear medicine and to provide base data for the criteria of the optimal administered activities. This study compares dosages and effective doses of 5 types of pediatric dose formulas(Clark rule, Area rule, Webster rule, Young rule, Solomon(Fried) rule) based on the dosage for adults of 2 types of radiopharmaceuticals($^{99m}Tc$-MDP, $^{99m}Tc$-Pertechnetate). The administered activities in adults, which is the criteria for calculating the Pediatric administered activities, used the value from the 'Nuclear Medicine' written by J-G Jeong & M-Ch Lee. and the administered activities by the radioactivity per effective dose(mSv/MBq) of the radiopharmaceuticals for calculating the effective dose used the value from ICRP 80 and the UNSCEAR 2008 Report. As a result of the study, the output of Young rule is the lowest, and its difference between other formulas is from minimum 1.7 times to maximum 3,4 times. The difference between administered activities of $^{99m}Tc$-MDP is maximum 309.9MBq and the effective dose is 3.76mSv. $^{99m}Tc$-Pertechnetate showed the figure at the maximum 154.9MBq and the effective dose has a difference of 5.50mSv. Since the pediatric dose formulas differ not only in administered activities but also in effective doses, the optimal administered activities have to be developed for optimization of medical radiation.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.2
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• pp.119-125
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• 2006

Purpose: To measure the dose for dose optimization at the reference point (A, B) and the critical organ with multi Purpose brachytherapy phantom (MPBP). For this wort the MPBP was custom made, and designed to reconstruct the treatment applicator using multi function applicator (MFA) in the same way as the treatment of patient. Materials and Methods: Dose measurements were made at the reference points (A, B) and the bladder with thermoluminescence dosimeter (TLD) for four patients with tandem and ovoid of uterine cervix cancer using the phantom. In Phantom, Total 20 times of the measurements were made with 5 times a patient. Results: The results of TLD measurements in MPBP phantom showed the relative error ranging from -3.2% to 3.8% at A point, and -1.4% to 4% at B point and 1.3% to 7.15% at the bladder of reference point. Conclusion: The reproducibility of dose measurement under the same condition as the treatment could be achieved using the custom-made MFA in phantom and the dose at the reference point (A, B) and bladder could be analyzed accurately. The measured dose acquired in MPBP can apply for the dose optimization.