• 한국항공운항학회지
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• 제26권2호
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• pp.91-97
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• 2018

High-energy charged particles are comprised of galactic cosmic rays and solar energetic particles which are mainly originated from the supernova explosion, active galactic nuclei, and the Sun. These primary charged particles which have sufficient energy to penetrate the Earth's magnetic field collide with the Earth's upper atmosphere, that is $N_2$ and $O_2$, and create secondary particles and ionizing radiation. The ionizing radiation can be measured at commercial flight altitude. So it is recommended to manage radiation dose of aircrew as workers under radiation environment to protect their health and safety. However, it is hard to deploy radiation measurement instrument to commercial aircrafts and monitor radiation dose continuously. So the numerical model calculation is performed to assess radiation exposure at flight altitude. In this paper, we present comparison result between measurement data recorded on several flights and estimation data calculated using model and examine the characteristics of the radiation environment in the atmosphere.

• 대한방사선방어학회:학술대회논문집
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• 대한방사선방어학회 2009년도 춘계 학술발표
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• pp.86-87
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• 2009

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• Journal of the Korean Data and Information Science Society
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• 제17권2호
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• pp.581-598
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• 2006

In many epidemiological and medical studies, a number of cancer mortalities in categorical classification may be considered as having Poisson distribution with person-years at risk depending upon time. The cancer mortalities have been evaluated by additive or multiplicative models with regard to background and excess risks based on several covariances such as sex, age at the time of bombings, time at exposure, or ionizing radiation, cigarette smoking habits, duration of smoking habits, etc. An interest herein is to examine an additive, synergistic, or antagonistic relationship between radiation exposures and cigarette smoking habits for cancer mortalities. The results revealed a highly significant antagonistic in uence for cancer mortalities from all non-hematologic findings, lung and respiratory system with negative interaction between radiation exposures and cigarette smoking amounts.

• Journal of Radiation Protection and Research
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• 제25권2호
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• pp.109-114
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• 2000

The SI unit of specific absorption rate (SAR) in W/kg in the electromagnetic (EM) field as non-ionizing radiation is exactly same as the SI unit of absorbed dose rate in Gy/s in the ionizing radiation field. The SI unit of both physical quantities can be expressed in $[m^{\cdot}s^{-3}]$. Where, the unit of absorbed dose, Gy stands for Gray. In EM biological interactions, the SAR equations are derived and the characteristics of EM field energy absorption in terms of the SAR are discussed and described on the mathematical basis.

• Clinical Endoscopy
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• 제55권1호
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• pp.22-32
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• 2022

Radiotherapy (RT) is a treatment modality that uses high-energy rays or radioactive agents to generate ionizing radiation against rapidly dividing cells. The main objective of using radiation in cancer therapy is to impair or halt the division of the tumor cells. Over the past few decades, advancements in technology, the introduction of newer methods of RT, and a better understanding of the pathophysiology of cancers have enabled physicians to deliver doses of radiation that match the exact dimensions of the tumor for greater efficacy, with minimal exposure of the surrounding tissues. However, RT has numerous complications, the most common being radiation proctitis (RP). It is characterized by damage to the rectal epithelium by secondary ionizing radiation. Based on the onset of signs and symptoms, post-radiotherapy RP can be classified as acute or chronic, each with varying levels of severity and complication rates. The treatment options available for RP are limited, with most of the data on treatment available from case reports or small studies. Here, we describe the types of RT used in modern-day medicine and radiation-mediated tissue injury. We have primarily focused on the classification, epidemiology, pathogenesis, clinical features, treatment strategies, complications, and prognosis of RP.

• Imaging Science in Dentistry
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• 제54권3호
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• pp.283-288
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• 2024

Purpose: Given the growing use of cone-beam computed tomography (CBCT) scans, this study assessed radiation exposure from these scans in the context of national guidelines and recommended dose limits. Materials and Methods: The current literature was reviewed to quantify the benefit of opportunistic diagnosis of carotid artery calcification relative to the potential risk of radiation-induced cancer. Results: The average radiation from CBCT at its largest field of view and highest resolution possible amounts to a reasonable but still low ionizing radiation exposure. This exposure is comparable to 22 days of background radiation and is notably lower than the radiation exposure from medical CT scans. According to the risk assessment analysis, the risk of stroke events involving internal and external carotid artery calcification (CAC) was 202 and 67 per 100,000 individuals, respectively. In contrast, the estimated risk of radiation-induced cancer associated with CBCT was notably lower, at 0.6 per 100,000. Conclusion: The present study advocates for a comprehensive assessment of CBCT scans encompassing the areas of the internal and external carotid arteries by a knowledgeable professional, given the potential advantages of early detection of vascular abnormalities. Dental professionals who take scans involving these areas need to be mindful of reporting these findings and refer patients to their primary care physician for further investigation.

• 한국식품과학회지
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• 제5권3호
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• pp.157-162
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• 1973

무균(無菌) 상태하에서 습윤한 여지위에 숙성(熟成)시킨 감자 괴경 박편(塊莖 薄片) $(1mm{\times}1.5cm)$을 재료로 방사선(放射線)의 작용기작(作用幾作)연구를 행하였다. Invertase, 핵산 및 호흡작용의 time courses를 결정하고 이들 세작용의 방사선(放射線)에 대한 민감도를 측정하였다. 세 작용 중 어느 것도 세포분열을 억제하는 선량에서 심하게 억제되지 않았다. $^3H-thymidine$의 incorporation 결과는 방사선(放射線)의 작용부위가 mitosis나 $G_2$ period에 존재할지도 모른다는 것을 암시한다.

• 방사선산업학회지
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• 제8권2호
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• pp.97-104
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• 2014

Postharvest diseases cause considerable losses to harvested fruits and vegetables worldwide. Fresh produce suspected of harboring postharvest disease must be treated to control any pathogens present. Although there are various treatments to control postharvest losses by pathogens, the current community is eager to take safer and more eco-friendly alternatives to help with human health and reduce environmental risks. Ionizing irradiation is a promising phytosanitary treatment that has a significant potential to control postharvest diseases in use worldwide. Although almost 19000 metric tons of sweet potatoes and various fruits are irradiated each year in six countries to control postharvest disease, irradiation continues to be a debate, with slow acceptance by industries. Irradiation alone is not effective as a fungicide, and an over dose affects the physical properties of irradiated products. A combination of irradiation with other treatments such as heating, biocontrol agents, chlorination, and nano Ag particles is to enhance their effectiveness. Challenges to the use of phytosanitary irradiation are an avoidance of irradiated postharvest and cost of the irradiation facilities, and thus consumers still need to be educated on the principles and benefits of irradiation and prepare an optimum economy of scale for commercial use. In this review, we evaluated the current phytosanitary irradiation, and combination with various other treatments to minimize the postharvest losses.

• 환경생물
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• 제28권4호
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• pp.212-217
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• 2010

각종 유전독성학적 물질로 인한 생물체내의 영향을 평가해보기 위해 E. fetida를 대상으로 본 연구를 수행하였다. 염화수은에 대한 DNA 손상을 알아보는 실험에서는 노출 시간에 상관없이 노출 농도에 비례한 유전자의 손상이 나타났다. 방사선이 지렁이의 DNA 손상에 미치는 영향을 알아본 실험에서도 역시 방사선 총 선량의 증가에 따라 DNA 손상이 증가하는 경향을 보였다. 염화수은에 48시간 동안 노출시키고 방사선을 조사한 지렁이의 세포를 comet assay하면, 수은 단독 처리군이나 방사선 단독 처리군에 비해 DNA의 손상이 유의적으로 크게 나타났다. 염화수은과 방사선 모두에 복합처리 된 지렁이의 DNA 손상치는 각각 단독 처리한 지렁이의 DNA 손상치를 합한 값보다 크게 나타나 두 요인의 상승작용이 확인되었다. 본 연구를 통해 지렁이의 세포내에서 수은과 방사선이 야기하는 DNA 손상을 측정하고, 두 인자의 복합처리에 따른 유전독성 상승효과를 관찰할 수 있었다. 이는 중금속과 방사선의 복합적인 효과를 나타낸 기존의 여러 연구결과와도 비교가 가능한 연구라고 사료되며, 향후 이를 보완하고 더 정확한 평가를 위해 지렁이 세포 내에서의 스트레스 반응 측정이나 효소 활성 실험등을 추가로 수행하여야 할 것이라고 생각된다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권16호
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• pp.7285-7290
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• 2015

Background: Although radiotherapy is one of the most effective strategies in the treatment of cancers, it is associated with short and long term side effects on normal tissues. Zataria multiflora Boiss (Laminacea) (ZM) has several biological properties such as antioxidant and anti-inflammation activities.Here we investigated cell killing effects of a hydroalcoholic Zataria multiflora extract on cell death induced by ionizing radiation in a human glioblastoma cell line (A172) and human non-malignant fibroblasts (HFFF2) in vitro. Materials and Methods: A172 and HFFF2 cells were treated with a hydroalcoholic extract of dried aerial parts of Zataria multiflora at different concentrations (25, 50, 100, 150 and $200{\mu}g/ml$) and then exposed to ionizing radiation (IR). Cell proliferation and DNA fragmentation were evaluated. Thymol content in the extract was analyzed and quantified by HPLC methods. Results: A172 cell proliferation was significantly inhibited by ZM. The percentage cell survival was $91.8{\pm}8.57$ for cells treated with $200{\mu}g/ml$ of ZM extract alone while it was $76.0{\pm}4.27$ and $66.2{\pm}8.42$ for cells treated with ZM and exposed to IR at doses of 3Gy and 6Gy, respectively. Radiation-induced apoptosis in A172 cells was significantly increased following treatment with ZM at doses of $200{\mu}g/ml$. ZM extract did not exhibit any enhanced cell killing effects and apoptosis caused by IR on HFFF2 cells. Conclusions: These data show selective radiosensitization effects of ZM in A172 cells apparently due to increased radiation-induced apoptosis.