• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.1
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• pp.91-98
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• 2008

Purpose: Radio-isotopes (RI) use has been steadily developing due to industrial and technical development in the modern medical society. Particularly, popularization of domestic cyclotrons dramatically enable hospitals to produce and use diagnostic radio-isotopes. Generally, only specific facilities such as hospitals, research institutes, nuclear power plants and universities can use radio-isotopes, they are also responsible for ventilation system. The strength of radioactivity in the air is strongly regulated and controlled by korea atomic energy law in Korea Institue of Nuclear Safety (KINS), so that air radioactivity exposure can lead to environmental pollution surrounding places. In this study, we'd like to find out the investigation and the present condition of the controlled ventilation system in domestic hospitals by an emission standard from KINS, and try to reach an agreement about how to use the ventilation system. Result: Definition of filters, features and structures of pre-filters, hepa-filters, charcol filters, filter exchange procedures and precautions are explained. RI deflation concentration and filter exchange cycle have been presented as a standard prescribed in the rules of KINS. The Radiation Control Management System (RCMS) introduced by Seoul National University Bundang Hospital linking to digital pressure gauge with computer controller in another medical facilities were described in details. Conclusions: The system of medical facilities using RI has been remarkably developing in 21 century. Especially, radiation safety control system has also been grown rapidly into the subdivision, specialization, advanced technology along with international technical improvement. However, As far as current RI ventilation system is concerned, it has nothing better than doing in the past. Preferentially, to reinforce this, more sophisticated system with strict periodic filter exchange and exhaust air control guidance should be introduced by applying brilliant domestic information technology for RCMS and digital gauge method. From personal point of view as a radiation safety manager, I have provide with present problems and improvements. Futhermore, more improved guidance should be conducted.

• Journal of the Korean Society of Radiology
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• v.5 no.5
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• pp.231-235
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• 2011

Radium is rock or soil of crust or uranium of building materials and thorium after radioactivity collapse process are created colorless and odorless inert gas that accrue well in sealed space like mine or basement. It inflow to lung circulate respiratory organ and caused lung cancer because of deposition of lung or bronchial tubes. Radium sheath of medical institution treat person's life is possible big danger to professional regarding radioactivity who has much amount exposed radioactivity and weaker immune patient. so we do this test. Using measuring instrument at test is real time radium measuring instrument, Professional Continuous Radon monitor, and measuring places are basement first floor and second floor of two hospitals and measure from 10 a.m to 3 p.m. Measurement result of Professional Continuous Radon monitor is minimum 14.8 Bq/$m^3$ to maximum 70.3 Bq/$m^3$ and show domestic baseline below 148 Bq/$m^3$, effective dose-rate is minimum 0.296 mSv to maximum 1.406 mSv that show 2.4 mSv, 10~58.3% level, exposed radiation amount from nature radiation one year.

• Journal of Radiation Protection and Research
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• v.26 no.2
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• pp.93-99
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• 2001

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 $30{\mu}g/g$ to $3{\mu}g/g$. This study established the voxel Monte Carlo calculation system and suggested the feasibility of precise dose calculation in therapeutic radiology.

• Journal of the Korean Society of Radiology
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• v.4 no.4
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• pp.5-10
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• 2010

The $Ca_2SiO_4$ phosphors doped by La with 0.1 wt%, 0.3 wt%, 0.5 wt%, and 1.0 wt% concentration were prepared by sintering at $1000^{\circ}C$ for 90 minutes in N2 atmosphere. The phosphors were ground in powdered form and were grouped in $100{\mu}m$ size, then the samples had been exposed to low energy X-ray and UV light. The TL glow curves were measured by heating the phosphors at $10^{\circ}C/s$ rate. There was no significantly meaningful correlation between the TL intensity and the doping level. The intensities of the TL peak measured from X-ray irradiated samples doped with 0.1 wt% were relatively strong. The activation energy and the frequency factor were 0.434 ~ 0.516 eV and 0.5 ~ 0.56, respectively. The intensities of the TL peak measured from UV irradiated samples doped with 0.3 wt% were relatively strong. The activation energy and frequency factor were 0.415 ~ 0.477 eV and 0.5 ~ 0.53, respectively. The TL process were found to be the 2nd order for both X-ray and UV irradiation. The TL intensity was increased linearly with the increase of the radiation dose. In summary, the $Ca_2SiO_4 phosphors developed in this study showed good TL characteristics at low energy X-ray and UV light. We believe they will be used as TLDs in near future for personal and environmental radiation detection dosimetry.

• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.46-53
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• 2018

This study was conducted to determine which greenhouse provided good environmental conditions for strawberry production, and performed better at conserving energy. Temperature, RH, VPD, $CO_2$, solar radiation, yield, and fuel consumption were the parameters analyzed. The temperatures of both greenhouses were well controlled in order to provide optimal day and night temperatures for strawberry production. The air inflated double layer greenhouse had higher RH values (more than 90% at night), which led to higher disease occurrence, in comparison to the conventional double layer greenhouse. Furthermore, the air inflated double layer greenhouse had lower VPD values than the conventional double layer greenhouse. Therefore, better RH and VPD were observed in the conventional double layer greenhouse. Higher $CO_2$ concentration was observed in the air inflated double layer greenhouse while the conventional double layer greenhouse ventilated better than the air inflated greenhouse, because of its side ventilators. Moreover, higher solar radiation in the conventional double layer greenhouse resulted in higher yield, in comparison to the air inflated double layer greenhouse. Thus, we can conclude that the conventional double layer greenhouse provided a better environment for crop growth, in comparison to the air inflated double layer greenhouse. Regarding fuel consumption, the air inflated double layer greenhouse had lower fuel consumption than the conventional double layer greenhouse. Therefore, from an energy consumption point of view, we can conclude that the air inflated double layer greenhouse performed better than the conventional double layer greenhouse.

• Journal of Mushroom
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• v.15 no.4
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• pp.264-268
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• 2017

In the 21st century, information and communication technology (ICT) worldwide presents a new vision for agriculture. Time and place, as well as the high-tech industry, to overcome barriers to the fusion of the so-called "smart agriculture," are changing the agricultural landscape. Core container production in precision agriculture for mushroom cultivation, optimal temperature, humidity, irradiation, self-regulation of factors such as carbon dioxide, and environment for mushroom cultivation were adopted. Lentinula edodes (shiitake) is an edible mushroom native to East Asia, cultivated and consumed in many Asian countries. It is considered to be medicinal in certain practices of traditional medicine. We used different controlled light sources (Blue-Red-White-combined LED, blue LED, red LED, and fluorescent light) with different LED radiation intensities (1.5, 10.5, and $20.5{\mu}mol/m^2s$ for LEDs) to compare growth and development. Mushrooms were treated with light in a 12-hour-on/12-hour-off cycle, and maintained in a controlled room at $19{\sim}21^{\circ}C$, with 80~90% humidity, and an atmospheric $CO_2$ concentration of 1,000 ppm for 30 days. Growth and development differed with the LED source color and LED radiation intensity. Growth and development were the highest at $10.5{\mu}mol/m^2s$ of blue LED light. After harvesting the fruit bodies, we measured their weight and length, thickness of pileus and stipe, chromaticity, and hardness. The $10.5{\mu}mol/m^2s$ blue-LED-irradiated group showed the best harvest results with an average individual weight of 39.82 g and length of 64.03 mm, pileus thickness of 30.85 mm and pileus length of 43.22 mm, and stipe thickness of 16.96 mm with fine chromaticity and hardness. These results showed that blue LED light at $10.5{\mu}mol/m^2s$ s exerted the best effect on the growth and development of L. edodes (shiitake) mushroom in the ICT-system container-type environment.

• Journal of Yeungnam Medical Science
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• v.4 no.1
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• pp.25-32
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• 1987

The object of this study was to determine the difference of radiation effect in different fractional doses and to establish optimal fractionation schedule on the whole-abdominal X-ray irradiation. Total 160 mice were irradiated with 150 KVP, 15 mA orthovoltage x-ray machine and two different fractionation (100 cGy/Fr. and 200 cGy/Fr.) were used. Body weight, hemoglobin and WBC count with differential count were analyzed according to the same amount of total dose, same field size and two different fractionation schedules. The result of this study were summarized as follows: There was no significant difference in body weight and hemoglobin concentration by sex or fractional dose. Leukopenic change was prominent in the 3,000 cGy irradiation group and the proportion of decrease was remarkable in the 200 cGy/Fr, group than 100 cGy/Fr, group. Progressive decrease of lymphocyte count and reciprocal increase of neutrophil count were noted as dose increment. The effect of the fractional does on WBC count and proportion of lymphocyte were significant. This suggests that judicious selection of fractional dose may be important in clinical radiotherapeutic practice.

• Applied Biological Chemistry
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• v.28 no.1
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• pp.28-35
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• 1985

Potato tubers treated at $4^{\circ}C$ for 4 weeks were irradiated with a dose of 0.12 kGy from $^{60}Co$ source and stored at $20^{\circ}C,\;70{\sim}90%$ humidity for 5 weeks. Changes of ${\alpha}-amylase$, peroxidase, indole acetic acid oxidase, indole acetic acid synthesizing enzyme activities were determined. In addition, treatment of gibberellin or indole acetic acid to tubers irradiated were carried out to examine reversal of sprout-inhibition of tubers irradiated. Results are as follows; 1. Irradiation by ${\gamma}-ray$ at 0. 12 kGy dose inactivated easily the enzyme activities in vitro. $D_{37}$ values obtained were 0.94, 0.36 kGy for ${\alpha}-amylase$ and peroxidase, respectively 2. Complete inhibition of the toter sprouting was resulted by the irradiation of tubers with a dose of 0.12 kGy. 3. The indole acetic acid oxidase activity increased 2 times immediately after irradiation. Meanwhile, indole acetic acid synthesizing activity decreased about $50{\sim}75%$ for 5-week storage in irradiated potatoes, whereas the activity increased about 3.5 times along with sprouting in non-irradiated tubers. 4. In morphological aspects, deformed buds with necrosis in the meristmatic tissue were developed in irradiated tubers. Treatment of gibberellin or indole acetic acid at the concentration of 100 or 20 ppm to the irradiated tubers reversed the sprout-inhibition partially. Nevertheless, the deformed buds remained without change.

• Journal of Radiation Protection and Research
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• v.23 no.4
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• pp.219-227
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• 1998

A solution containing $^{85}Sr$, $^{103}Ru$ and $^{134}Cs$ was applied to Chinese cabbage in a greenhouse via foliar spraying at 5 different times during its growth. Interception of the applied activity by plant showed no difference among radionuclides and increased with decreasing time interval between application and harvest. The maximum interception factor observed was 0.87. Percentages of the intercepted activity remaining in the whole leaves at harvest varied $16{\sim}58%$ for $^{85}Sr$, $15{\sim}73%$ for $^{103}Ru$ and $33{\sim}64%$ for $^{134}Cs$, with application time and those for the inner leaves (without 6 outmost leaves) varied $2{\sim}35%$, $0.4{\sim}46%$ and $14{\sim}40%$, respectively. It was demonstrated that rain plays an important role in weathering loss of the activity. Tying the upper end of the plant prior to the last application lowered interception and remaining activity in the inner leaves by factors of $3{\sim}4$. Present results can be referred to in predicting the radionuclide concentration in Chinese cabbage and deciding counter-measures at the time of an accidental release from the nuclear installation.

• Journal of Radiation Protection and Research
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• v.32 no.1
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• pp.1-8
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• 2007

A model for radiological dose assessment in an urban environment, METRO-K has been developed. Characteristics of the model are as follows ; 1) mathematical structures are simple (i.e. simplified input parameters) and easy to understand due to get the results by analytical methods using experimental and empirical data, 2) complex urban environment can easily be made up using only 5 types of basic surfaces, 3) various remediation measures can be applied to different surfaces by evaluating the exposure doses contributing from each contamination surface. Exposure doses contributing from each contamination surface at a particular location of a receptor were evaluated using the data library of kerma values as a function of gamma energy and contamination surface. A kerma data library was prepared fur 7 representative types of Korean urban buildings by extending those data given for 4 representative types of European urban buildings. Initial input data are daily radionuclide concentration in air and precipitation, and fraction of chemical type. Final outputs are absorbed dose rate in air contributing from the basic surfaces as a function of time following a radionuclide deposition, and exposure dose rate contributing from various surfaces constituting the urban environment at a particular location of a receptor. As the result of a contaminative scenario for an apartment built-up area, exposure dose rates show a distinct difference for surrounding environment as well as locations of a receptor.