• Journal of Radiation Protection and Research
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• v.46 no.1
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• pp.24-31
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• 2021

Decommissioning efforts are underway at the reactor where the accident occurred, namely the damaged Tokyo Electric Power Company (TEPCO) Fukushima Daiichi Nuclear Power Plant (FDNPP). However, a large amount of groundwater flowing into the site has become contaminated with radioactive substances and is stored in tanks on site, which has hampered the decommissioning work. Although the inflow of groundwater has been greatly reduced through measures such as the construction of frost walls, approximately 170 ㎥ of water treated by the Advanced Liquid Processing System (ALPS) is being stored in tanks, each day. The tanks used to store this treated water are expected to become full by around the summer of 2022. It is not easy to get people to understand the efforts of all concerned parties, and providing clear information to these concerned parties is also a challenge. Questions have also been raised regarding whether other alternatives have been fully explored in the ALPS subcommittee. Some people have commented that the answers to the questions raised regarding the biological effects of tritium transmutation are inadequate. Some suspect that the answers are too detailed and incomprehensible, and that the respondents may be manipulating the public with some malicious intent. In any case, each possible plan presents both advantages and disadvantages, depending on the people who are involved. That makes it an ethical and vexing issue that can sway decisions, as perspectives change. While the environmental release plan is scientifically safe, it may represent a painful alternative. On the other hand, a more careful and imaginative approach to the idea of continued storage in tanks or other forms of storage may reveal some troublesome hidden disadvantages. Under these circumstances, experts must be prepared to answer people's questions in a comprehensive and robust manner.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.489-495
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• 2017

To prevent over supplying of workforce with radiologic technologist license, effort to create new jobs related to radioactive from medical field and radiation-related academia should be put first. For this, investigating present condition is required by close analysis of working force supply related to radiation. Therefore in this research, basic data useful for developing future radiation-related policy and plan is provided from analysis of present supplying condition of radiologic technologists in Korea. Results are as following. First, number of people qualified as radiologic technologists consistently increased; 15,639 more people took the license in 2014 compared with 2004, showing growth rate of 75.6%. Second, about 65.7%, most of workforce related to radiation engaged in medical area. Third, estimating supply and demand of radiologic technologists by time period of 5 years from 2015 to 2040, about 6,000 number of surplus work force was predicted around 2020. Fourth, satisfaction of graduates who majored in radiology was quite low for their first occupation. These results implicate necessity of systemic supplementation which can expand medical areas where radiologic technologists can work.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.3
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• pp.42-52
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• 2015

Since the tax-free system for overseas laborers was implemented in 1974, the tax-free limits of international air crew, overseas construction workers and crewmen of deep-sea fishing ships and ocean-going ships had been identical by 2005, but there are big differences, currently. The Ministry of Strategy and Finance pointed out the poor working environments and international competitiveness of the industries to explain the reason for the differential tax-free limit. From this perspective, the fairness of the tax-free system for overseas laborers was analyzed. This is an empirical study, based on the objective fact. The study finding showed that international air crew were working in the structural flight work environments to threaten the right of health due to jet lag and excessive exposure to high-altitude cosmic radiation. Therefore, it was analyzed there should be a proper system reform to apply the tax-free limits to international air crew which are identical to those applied to overseas construction workers and crewmen of deep-sea fishing ships and ocean-going ships, for a fair taxation.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3816-3823
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• 2022

This work analyzed the dosimetric difference between the intensity modulated radiotherapy (IMRT), partial/single/double-arc volumetric modulated arc therapy (PA/SA/DA-VMAT) techniques in treatment planning for treating more than one target of lung cancer at different isocenters. IMRT and VMAT plans at different isocenters were created systematically using a Harold heterogeneous lung phantom. The conformity index (CI), homogeneity index (HI), gradient index (GI), dose-volume histogram and mean and maximum dose of the PTV were calculated and analyzed. Furthermore, the dose-volume histogram and mean and maximum doses of the OARs such as right lung, contralateral lung and non GTV were determined from the plans. The IMRT plans showed the superior target dose coverage, higher mean and maximum values than other VMAT techniques. PA-VMAT technique shows more lung sparing and DA-VMAT increases the V_5/10/20 values of contralateral lung than other VMAT and IMRT techniques. The IMRT technique achieves highly conformal dose distribution to the target than other VMAT techniques. Comparing to the IMRT plans, the higher V_5/10/20 and mean lung dose were observed in the contralateral lung in the DA-VMAT.

• The Journal of Korean Society for Radiation Therapy
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• v.32
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• pp.17-29
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• 2020

Purpose: The purpose of this work was to investigate the dosimetric impact of mixed energy partial arc technique on prostate cancer VMAT. Materials and Methods: This study involved prostate only patients planned with 70Gy in 30 fractions to the planning target volume (PTV). Femoral heads, Bladder and Rectum were considered as oragan at risk (OARs). For this study, mixed energy partial arcs (MEPA) were generated with gantry angle set to 180°~230°, 310°~50° for 6MV arc and 130°~50°, 310°~230° for 15MV arc. Each arc set the avoidance sector which is gantry angle 230°~310°, 50°~130° at first arc and 50°~310° at second arc. After that, two plans were summed and were analyzed the dosimetry parameter of each structure such as Maximum dose, Mean dose, D2%, Homogeneity index (HI) and Conformity Index (CI) for PTV and Maximum dose, Mean dose, V70Gy, V50Gy, V30Gy, and V20Gy for OARs and Monitor Unit (MU) with 6MV 1 ARC, 6MV, 10MV, 15MV 2 ARC plan. Results: In MEPA, the maximum dose, mean dose and D2% were lower than 6MV 1 ARC plan(p<0.0005). However, the average difference of maximum dose was 0.24%, 0.39%, 0.60% (p<0.450, 0.321, 0.139) higher than 6MV, 10MV, 15MV 2 ARC plan, respectively and D2% was 0.42%, 0.49%, 0.59% (p<0.073, 0.087, 0.033) higher than compared plans. The average difference of mean dose was 0.09% lower than 10MV 2 ARC plan, but it is 0.27%, 0.12% (p<0.184, 0.521) higher than 6MV 2 ARC, 15MV 2 ARC plan, respectively. HI was 0.064±0.006 which is the lowest value (p<0.005, 0.357, 0.273, 0.801) among the all plans. For CI, there was no significant differences which were 1.12±0.038 in MEPA, 1.12±0.036, 1.11±0.024, 1.11±0.030, 1.12±0.027 in 6MV 1 ARC, 6MV, 10MV, 15MV 2 ARC, respectively. MEPA produced significantly lower rectum dose. Especially, V70Gy, V50Gy, V30Gy, V20Gy were 3.40, 16.79, 37.86, 48.09 that were lower than other plans. For bladder dose, V30Gy, V20Gy were lower than other plans. However, the mean dose of both femoral head were 9.69±2.93, 9.88±2.5 which were 2.8Gy~3.28Gy higher than other plans. The mean MU of MEPA were 19.53% lower than 6MV 1 ARC, 5.7% lower than 10MV 2 ARC respectively. Conclusion: This study for prostate radiotherapy demonstrated that a choice of MEPA VMAT has the potential to minimize doses to OARs and improve homogeneity to PTV at the expense of a moderate increase in maximum and mean dose to the femoral heads.

• The Korean Journal of Nuclear Medicine Technology
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• v.21 no.2
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• pp.13-27
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• 2017

Purpose In the procedure of domestic medical radioactive self-disposal, there are many requests of supplementation and difficulties on the screening process. In this regard, presentation of basic guideline will improve the work processing efficiency of medical institution radioactive waste. From 2015 to 2016, We reviewed and compared a supplementary requests of domestic fifteen medical institution radioactive self-disposal Plan & Procedure manual. In connection with this, we derive the details of the radioactive waste document based on the relative regulation of nuclear safety Act. The representative supplementary requests of Korea Institute of Nuclear Safety are disposal method of non-flammability radioactive waste, storage method of scheduled self-disposal waste, the legitimacy of self-disposal and pre-treatment of self-disposal, reference radioactivity of disused filter and output of storage period, attachment the evidential matter of measurement efficiency when using a gamma counter. Through establishing a medical radioactive waste guideline, we can clearly suggest a classification standard of radioactive nuclide and the type of occurrence. As a result, we can confirm the reduction of examination processing period while preparing a self-disposal document and there is no spending expenses for business agency. Also, the storage efficiency of facility will better and reduce the economic expenses. On the basis of this guideline, we will expect a contribution to the improvement of work efficiency for officials who has a working-level difficulty of radioactive waste self-disposal.

• Progress in Medical Physics
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• v.28 no.1
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• pp.11-15
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• 2017

Relative biological effectiveness (RBE) of particle beam needs to be evaluated at particle beam therapy centers before the clinical application of the particle beam. However, since RBE analysis is implemented manually, it is useful to have a tool that can easily and effectively handle the data of experiments to generate cell survival curve and to analyze RBE simultaneously. In this work, the development of a program for RBE analysis of particle beam therapy was presented. This RBE analysis program was developed to include two parts; fitting the cell survival curves to linear-quadratic model and calculating the RBE values at a certain endpoint using fitting results. This program was also developed to simultaneously compare and analyze the template results that stored experiment data with photon and particle beam irradiations. The results of the cell survival curve obtained by each irradiation can be analyzed by the user on a desired data after reading the template stored in the easy-to-use excel file. The analysis results include the cell survival curves with error range, which are appeared in the screen and the ${\alpha}$ and ${\beta}$ parameters of linear-quadratic model with 95% confidence intervals, RBE values, and $R^2$ values to evaluate goodness-of-fit of survival curves to model, which are stored in a text cvs file. This software can generate cell survival curve, fit to model, and calculate RBE all at once with raw experiment data, so it helps users to save time for data handling and to reduce the possibility of making error on analysis. As a coming plan, we will create a user-friendly graphical user interface to present the results more intuitively.

• Progress in Medical Physics
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• v.16 no.1
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• pp.24-31
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• 2005

The stereotactic radiosurgery (SRS) describes a method of delivering a high dose of radiation to a small tar-get volume in the brain, generally in a single fraction, while the dose delivered to the surrounding normal tissue should be minimized. To perform automatic plan of the SRS, a new method of multi-isocenter/shot linear accelerator (linac) and gamma knife (GK) radiosurgery treatment plan was developed, based on a physical lattice structure in target. The optimal radiosurgical plan had been constructed by many beam parameters in a linear accelerator or gamma knife-based radiation therapy. In this work, an isocenter/shot was modeled as a sphere, which is equal to the circular collimator/helmet hole size because the dimension of the 50% isodose level in the dose profile is similar to its size. In a computer-aided system, it accomplished first an automatic arrangement of multi-isocenter/shot considering two parameters such as positions and collimator/helmet sizes for each isocenter/shot. Simultaneously, an irregularly shaped target was approximated by cubic structures through computation of voxel units. The treatment planning method by the technique was evaluated as a dose distribution by dose volume histograms, dose conformity, and dose homogeneity to targets. For irregularly shaped targets, the new method performed optimal multi-isocenter packing, and it only took a few seconds in a computer-aided system. The targets were included in a more than 50% isodose curve. The dose conformity was ordinarily acceptable levels and the dose homogeneity was always less than 2.0, satisfying for various targets referred to Radiation Therapy Oncology Group (RTOG) SRS criteria. In conclusion, this approach by physical lattice structure could be a useful radiosurgical plan without restrictions in the various tumor shapes and the different modality techniques such as linac and GK for SRS.

• The Journal of Korean Society for Radiation Therapy
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• v.17 no.2
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• pp.87-94
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• 2005

Purpose : Heavy metal use when producing the block from the workshop. At this time, production of heavy metal dust and fume gives risk in human. This like heavy metal to improve seriousness through measurement and analysis. And by the quest in solution is purpose of this thesis. Materials and Methods : Organization is Inductively Coupled Plasma Atomic Emission Spectrometer, and the object is Deajeon city 4 workshops in university hospital radiation oncology (Bismuth, Lead, Tin and cadmium). Method is the ppb the pumping it does at unit, comparison analysis. And the Calculation heavy metal standard level in air through heavy metal standard level in body and blood, so Heavy metal temporary standard set. Results : Subterranean existence room air quality the administration laws appointed Lead and Cadmium's exposure recommend that it is $3{\mu}g/m^3\;and\;2{\mu}g/m^3$. And Bismuth and Tin decides $7{\mu}g/m^3\;and\;6{\mu}g/m^3$ through standard level in air heavy metal and standard level in body and blood. Heavy metal measurement level of workshops in 4 university hospital Daejeon city compares with work existence and nonexistence. On work nonexistence almost measurement level is below the recommend level. But work existence case express high level. Also consequently in composition ratio of the block is continuous with the detection ratio. Conclusion : Worker's heavy metal contamination imbrued serious for solution founds basic part. In hospital may operation on local air exhauster and periodical efficiency check, protector offer, et al. And worker have a correct understanding part of heavy metal contamination, and have continuous interest, health control. Finally, learned society sphere administer to establishment standard level and periodical measurement. And it founds basic solution plan of periodical special health checkup.

• Journal of the Korean Society of Radiology
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• v.8 no.7
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• pp.467-477
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• 2014

The purpose of this study is to offer data base for establishment of dental training x-ray generator based safety usage through surveying real radiation safety management state of radiation worker's in plan of operations that have dental training x-ray generators and use it. For it, comprehensive references were surveyed referring reports of current state of regulation technique development and domestic radiation safety evaluation and nuclear related legislation regarding radiation safety management of dental training x-ray generators. On the basis of it, questionnaires were filled in about respondent's general characteristic radiation safety manager's status current state of radiation safety management and the level of knowledge & consciousness. For the study, the survey was conducted to 224 people of radiation safety managers and university graduates training assistants and full-time professors who can treat dental training x-ray generators in education center. through this survey 95 questionnaires were used as analysis materials except the insufficient and omitted responses. As a method of analysis, the frequency and percentage were figured out with the general characteristics and safety manager's status. Chi-square test for frequency and correlation per question analysis and Pearson correlation analysis for crosslevel correlation were done with current state of radiation safety management and knowledge & consciousness level. As a result, running dental training x-ray generators was dealt with by 20's to 40's who have high education level over post undergraduate degree and major in dental hygienic. In addition, female have higher consciousness level for radiation safety management than male. It shows significal linear relation statistically(${\chi}^2$ >5, 0.1${\chi}^2$ >5, 0.3${\chi}^2$ >5, 0.3