• Korean Journal of Environmental Biology
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• v.29 no.3
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• pp.236-240
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• 2011

Mercury known as quicksilver, is the most common cause of heavy metal toxicity. Toxicity caused by excessive mercury exposure is now being recognized as a widespread environmental problem and is continuing to attract a great deal of public concerns. The mercury genotoxicity could be its effect on DNA repair mechanisms, which constitute the defense system designated to protect genome integrity. The objective of this study is to confirm that mercuric chloride inhibits the repair of gamma ray-induced DNA damage. The earthworm of Eisenia fetida was chosen for this study because it is an internationally accepted model species for toxicity testing with a cosmopolitan distribution. Experiments were done to identify the levels of DNA damage and the repair kinetics in the coelomocytes of E. fetida irradiated with 20 Gy gamma rays alone or with gamma rays after 40 mg $kg^{-1}$ $HgCl_2$ treatment by means of the single cell gel electrophoresis assay. The Olive tail moments were measured during 0~96 hours after irradiation. The repair time in the animals treated with the combination of $HgCl_2$ and ionizing radiation was nearly five times longer than that in the animals treated with ionizing radiation alone. Also, E. fetida exposed to mercury showed a statistically lower repair efficiency of gamma ray-induced DNA damage. The results suggest that the mercury could even have deleterious effects on the DNA repair system. Influence of mercury on the DNA repair mechanisms has been confirmed by this study.

• Journal of the Korean Society of Radiology
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• v.14 no.4
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• pp.433-437
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• 2020

Principles of Radiation Detection and measurement include luminescence, ionization and chemical reactions. In this study, thermoluminescent properties were analyzed by exposure radiation on the glass for protective glass of smart phone. In order to analyze the thermoluminescent characteristics by radiation, 6 MV X-ray 100 cGy was irradiated to the powder annealing at 300 ℃ by grinding the tempered glass and original tempered glass. As a result of measuring the amount of thermoluminescent respectively irradiated material, the thermoluminescent increased by 3 times in the tempered glass, and when the tempered glass was grinding by powder the thermoluminescent was 2.4 times increased. Based on these results, the liquid crystal protective glass of the smart phone is evaluated as a tracer material to evaluate the radiation exposure and dose of the personal radiation monitoring.

• Proceedings of the Korean Society of Radiological Science
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• 1992.10a
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• pp.121-122
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• 1992

• Journal of the korean veterinary medical association
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• v.53 no.3
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• pp.164-166
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• 2017

• Restorative Dentistry and Endodontics
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• v.34 no.1
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• pp.61-68
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• 2009

This study was performed to assess the radiopacity of a variety of root canal sealers according to the specification concerning root canal sealers. Ten materials including Tubli-$Seal^{TM}$. Kerr Pulp Canal $Sealer^{TM}$, AH $26^{(R)}$, AH $plus^{(R)}$, AH plus $jet^{TM}$, Ad sea $1^{TM}$. $Sealer^{TM}$, $NOGENOL^{TM}$, ZOB $seal^{TM}$, $Epiphany^{TM}$ and dentin were evaluated in this study. In the first part, densitometric reading of an each step of aluminum step wedge on occlusal film was performed at different voltage and exposure time. In the second part, ten specimens were radiographed simultaneously with an aluminum step wedges on the occlusal films under decided condition. The mean radiographic density values of the materials were transformed into radiopacity expressed equivalent thickness of aluminum (mm Al). The following results were obtained. 1. Among the various conditions, the appropriate voltage and exposure time that meet the requirement density was 60 kVp at 0.2 s 2. All of the materials had greater radiopacity than 3 mm Al requirement of ANSI/ADA specification No. 57 (2000) and ISO No. 6876 (2001) standards. 3. The radiopacity of materials increased as thickness of materials increased. 4. The mm Al value of each specimen at 1mm in thickness has a significant difference in the statistics. It suggests that root canal sealers have a sufficient radiopacity that meet the requirement.

• Journal of radiological science and technology
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• v.44 no.6
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• pp.599-605
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• 2021

The International Electrotechnical Commission (IEC) 62494-1 has defined the exposure index (EI) that have a proportional relationship with the dose incident on the image receptor, and target exposure index (EI_T), deviation index (DI). In this study, an appropriate EI_T for skull radiography was established through the diagnostic reference level (DRL) and changes in DI were confirmed. Entrance surface dose (ESD) and EI were obtained using the computed radiography system displayed the EI as per IEC on console and skull phantom by experiment based on the national average exposure conditions announced in 2012 and 2019. And appropriate EI_T was established by applying the DRL in 2012 and 2019. As a results, the EI_T is changed according to the change in the DRL, and the exposure condition that becomes the ideal DI according to the change in the EI_T also has a difference of about 1.41 times. DRL is recommended to optimize the patient dose, however it is difficult to measure in real time at medical institutions whereas EI and DI are displayed on the console at the same time as exposure. When the EI_T is set based on the DRL and the DI is closed to an ideal value, it is useful as a patient dose management tool. Therefore, when the EI_T is periodically managed along with the revision of the DRLs, the patient dose can be optimized through the EI, EI_T and DI.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.463-464
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• 2003

현대인들은 다양한 전자기기 휴대폰, 컴퓨터, 전자레인지로부터 발생하는 전자파에 뇌를 노출시키고 있다. 전자기기의 전자파는 뇌에 중대한 손상을 가져올 수 있으며, 조기 노화를 초래할 수 있다고 경고하고 있다. 전자파의 실질적인 위험은 뇌가 열을 받는 것이 아니라 비열방사선이라고 널리는 강도가 낮은 방사선이라고 한다. 휴대폰, 컴퓨터의 모니터에서 발생되는 전자파에 장시간 노출로 인한 각종 전자파 유해가 생기고 여러 가지 신경 계통에 대한 장해가 증가하고 있다. 전자파가 인체에 미치는 영향에 대한 많은 연구가 이루어지고 있으나 서로 상반되는 연구결과가 많이 나타나고 있다. (중략)

• Proceedings of the Korean Society of Disaster Information Conference
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• 2023.11a
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• pp.224-225
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• 2023

방사능재난 시 주민의 방사선 피폭을 최소화하기 위하여 대피 및 소개가 신속하게 이루어져야 한다. 주민이 휴대용 방사선 계측기를 통하여 방사능 오염 발생을 감지해 사전에 신속히 대피할 수 있다면, 방사능재난 대응에 기여할 수 있을 것으로 사료된다. 본 논문에서는 방사능재난 시 주민이 사용하기 용이한 방사선 계측기를 제시하고, 향후 보완하여야 하는 사항에 대해 검토하였다.

• Journal of radiological science and technology
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• v.33 no.4
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• pp.355-362
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• 2010

This study determines a range of CT parameter values in Brain CT which are minimizing patient absorption dose without compromising the image quality and optimal exposure condition. We measured dose and image noise using conventional CT parameters in Brain CT. In additon, we evaluated dose, SNR and PSNR of head phantom images while changing kVp and rotation time. In this study, effectiveness of dose that was achieved from dose reproducible experiments in conventional head CT condition is determined by changing kVp and rotation time. Dose and PSNR is related to low dose-high resolution condition. In conclusion, we suggest that using proposed conditions is effective for imaging to compare with conditions proposed by the manufacturer.

• Journal of Digital Contents Society
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• v.13 no.3
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• pp.421-429
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• 2012

Lately, the number of interventional radiology is increased by the extension of procedure in medical radiation, and radiation exposure may be appeared differently by interventional radiologists, it is caused increase of radiation dose for radiation worker, patient, and radiologists. This study has done a comparative analysis characteristic of radiation exposure for five radiologists who executed interventional cardiology for 303 patients in S university hospital of Gyeong-Buk from Nov. 1, 2011 to Jan. 31, 2011. The average exposure time of five radiologists was 697.95sec. The average of cumulative DAP(exp) for patients was $52,730mGycm^2$ and the average of total DAP for patients was $104,875.14mGycm^2$. The average of frames for image was 855.52 frames in acquired images, and the average of frames for images was 802.2 frames in exposure images. They were statistically significant differences (p<0.05). Exposure time, cumulative DAP(fluro), cumulative DAP(exp), total DAP, acquired image, and exposure image were high correlation except cumulative DAP(exp), and acquired runs in x-ray exposure characteristics of machine. Exposure time was a great influence on radiologist. It signified that the more exposure time lead to the more radiation dose for radiologist. Radiation dose is related to ability, experience, difficulty, and precision of procedures in interventional procedure. The number of angiography and exposure time is difficult to control by radiologists. Therefore, it is in need of reasonable system which was evaluated the real dose of medical teams in interventional proceedings. We think that self education and training are required to reduce radiation dose for radiologists and radiation workers.