• Journal of Radiation Protection and Research
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• 제46권1호
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• pp.14-23
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• 2021

Background: For radiological protection and control, the International Commission on Radiological Protection (ICRP) provides the nominal risk coefficients related to radiation exposure, which can be extrapolated using the excess relative risk and excess absolute risk obtained from the Life Span Study of atomic bomb survivors in Hiroshima and Nagasaki with the dose and dose-rate effectiveness factor (DDREF). Materials and Methods: Since it is impossible to directly estimate the radiation risk at doses less than approximately 100 mSv only from epidemiological knowledge and data, support from radiation biology is absolutely imperative, and thus, several national and international bodies have advocated the importance of bridging knowledge between biology and epidemiology. Because of the accident at the Tokyo Electric Power Company (TEPCO)'s Fukushima Daiichi Nuclear Power Station in 2011, the exposure of the public to radiation has become a major concern and it was considered that the estimation of radiation risk should be more realistic to cope with the prevailing radiation exposure situation. Results and Discussion: To discuss the issues from wide aspects related to radiological protection, and to realize bridging knowledge between biology and epidemiology, we have established a research group to develop low-dose and low-dose-rate radiation risk estimation methodology, with the permission of the Japan Health Physics Society. Conclusion: The aim of the research group was to clarify the current situation and issues related to the risk estimation of low-dose and low-dose-rate radiation exposure from the viewpoints of different research fields, such as epidemiology, biology, modeling, and dosimetry, to identify a future strategy and roadmap to elucidate a more realistic estimation of risk against low-dose and low-dose-rate radiation exposure.

• 한국의학물리학회지:의학물리
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• 제28권1호
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• pp.27-32
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• 2017

We investigated the effect of a commercial iterative reconstruction technique (iDose, Philips) on the image quality and the dose calculation for the treatment plan. Using the electron density phantom, the 3D CT images with five different protocols (50, 100, 200, 350 and 400 mAs) were obtained. Additionally, the acquired data was reconstructed using the iDose with level 5. A lung phantom was used to acquire the 4D CT with the default protocol as a reference and the low dose (one third of the default protocol) 4D CT using the iDose for the spine and lung plans. When applying the iDose at the same mAs, the mean HU value was changed up to 85 HU. Although the 1 SD was increased with reducing the CT dose, it was decreased up to 4 HU due to the use of iDose. When using the low dose 4D CT with iDose, the dose change relative to the reference was less than 0.5% for the target and OARs in the spine plan. It was also less than 1.1% in the lung plan. Therefore, our results suggests that this dose reduction technique is applicable to the 4D CT image acquisition for the radiation treatment planning.

• Journal of Korean Neurosurgical Society
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• 제54권6호
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• pp.461-466
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• 2013

Objective : Although curcumin has a protective effect on bone remodeling, appropriate therapeutic concentrations of curcumin are not well known as therapeutic drugs for osteoporosis. The purpose of this study was to compare the bone sparing effect of treatment of low-dose and high-dose curcumin after ovariectomy in rats. Methods : Forty female Sprague-Dawley rats underwent either a sham operation (the sham group) or bilateral ovariectomy (OVX). The ovariectomized animals were randomly distributed among three groups; untreated OVX group, low-dose (10 mg/kg) curcumin administered group, and high-dose (50 mg/kg) curcumin group. At 4 and 8 weeks after surgery, serum biochemical markers of bone turnover were analyzed. Bone histomorphometric parameters of the 4th lumbar vertebrae were determined by micro-computed tomography (CT). In addition, mechanical strength was determined by a three-point bending test. Results : High-dose curcumin group showed significantly lower osteocalcin, alkaline phosphatase, and the telopeptide fragment of type I collagen C-terminus concentration at 4 and 8 weeks compared with the untreated OVX group as well as low-dose curcumin group. In the analyses of micro-CT scans of 4th lumbar vertebrae, the high-dose curcumin treated group showed a significant increase in bone mineral densities (p=0.028) and cortical bone mineral densities (p=0.036) compared with the low-dose curcumin treated group. Only high-dose curcumin treated group had a significant increase of mechanical strength compared with the untreated OVX group (p=0.015). Conclusion : The present study results demonstrat that a high-dose curcumin has therapeutic advantages over a low-dose curcumin of an antiresorptive effect on bone remodeling and improving bone mechanical strength.

• Asian Pacific Journal of Cancer Prevention
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• 제14권7호
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• pp.4121-4126
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• 2013

Objective: Low dose radiation may stimulate the growth and development of animals, increase life span, enhance fertility, and downgrade the incidence of tumor occurrence.The aim of this study was to investigate the antitumor effect and hormesis in an erythrocyte system induced by low-dose radiation. Methods: Kunming strain male mice were subcutaneously implanted with S180 sarcoma cells in the right inguen as an experimental in situ animal model. Six hours before implantation, the mice were given 75mGy whole body X-ray radiation. Tumor growth was observed 5 days later, and the tumor volume was calculated every other day. Fifteen days later, all mice were killed to measure the tumor weight, and to observe necrotic areas and tumor-infiltration-lymphoreticular cells (TILs). At the same time, erythrocyte immune function and the level of 2,3-diphosphoglyceric acid (2,3-DPG) were determined. Immunohistochemical staining was used to detect the expression of EPO and VEGFR of tumor tissues. Results: The mice pre-exposed to low dose radiation had a lower tumor formation rate than those without low dose radiation (P < 0.05). The tumor growth slowed down significantly in mice pre-exposed to low dose radiation; the average tumor weight in mice pre-exposed to low dose radiation was lighter too (P < 0.05). The tumor necrosis areas were larger and TILs were more in the radiation group than those of the group without radiation. The erythrocyte immune function, the level of 2,3-DPG in the low dose radiation group were higher than those of the group without radiation (P < 0.05). After irradiation the expression of EPO of tumor tissues in LDR group decreased with time. LDR-24h, LDR-48h and LDR-72h groups were all statistically significantly different from sham-irradiation group. The expression of VEGFR also decreased, and LDR-24h group was the lowest (P < 0.05). Conclusion: Low dose radiation could markedly increase the anti-tumor ability of the organism and improve the erythrocyte immune function and the ability of carrying $O_2$. Low-dose total body irradiation, within a certain period of time, can decrease the expression of hypoxia factor EPO and VEGFR, which may improve the situation of tumor hypoxia and radiosensitivity of tumor itself.

• 한국콘텐츠학회논문지
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• 제14권1호
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• pp.356-363
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• 2014

소아 CT 촬영시 피폭선량을 저감시킬 수 있는 조건을 찾기 위하여 pediatric phantom을 이용하여 소아 방사선량을 비교 분석하였다. 관전류변동제어(tube current modulation:TCM) 방식과 low dose CT protocol(LDCTP)에 따라 소아 검사를 시행하였으며, 검사는 brain, chest, abdomen-pelvis 부위를 전산화 단층촬영 장치를 이용한 3개의 검사 프로토콜을 사용하였다. 거의 모든 MDCT 장치는 volume CT dose index(CTDIvol), dose length product(DLP)와 유효선량 평가 결과를 기록, 보관하고 있으며, 이러한 정보들은 환자들의 방사선 노출 및 위험도를 평가하는 데 필수적이다. 방사선 노출 위험도를 감소시키기 위해서 적정화 및 정당화 원칙을 반드시 준수해야 한다. 관전압(kV)에 따른 TCM 방식을 사용하였을 경우 kV가 낮아질수록 유효선량이 낮아지는 경향을 나타내었으며, low dose CT protocol을 사용한 경우가 유효선량이 상대적으로 더 적은 것을 알 수 있었다. 또한 평균 유효선량은 brain, chest, abdomen-pelvis CT의 결과가 독일의 reference dose 보다 각각 47%, 13.8%, 25.7%로 더 낮게 나타났고. 영국의 reference dose와 비교해도 55.7%, 10.2%, 43.6%에 불과했다. 결론적으로 선량 감소를 위해 주의할 것은 body-weight based tube current adaption을 포함한 TCM, 그리고 LDCTP 등 모든 선량 감소 방안을 이용하여야 한다.

• 대한방사성의약품학회지
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• 제7권1호
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• pp.50-55
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• 2021

Low-dose radiotherapy has been known to have anti-inflammatory activity and been used for treatment of pneumonia together with anti-serum and sulfanilamide. However, it rapidly discontinued after the development of various antibiotics showing outstanding effect. Recently, it was re-considered to treat COVID-19 which has very limited treatment such as remdesivir and dexamethasone. So, several studies of COVID-19 therapy using low-dose radiation were reported very recently. They showed that low-dose radiation of 0.5~1.5 Gy were useful for decreasing the oxygen consumption and hospitalization period of COVID-19 patients without adverse reaction. Radiopharmaceuticals such as [⁹⁹mTc]Tc-macroaggregated albumin (MAA) also might be used for low-dose radiotherapy. Administration of vitamin D having anti-inflammatory effect would also be helpful for therapy with synergistic effect.

• 한국산업융합학회 논문집
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• 제15권3호
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• pp.71-77
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• 2012

This study gives the optimal reaction conditions, reaction mechanisms, reaction rates leaded from the oxidation of phenol by electron beam accelerator and ozone used for recent water treatment. It gives the new possibility of water treatment process to effectively manage industrial sewage containing toxic organic compounds and biological refractory materials. The high decomposition of phenol was observed at the low dose rate, but at this low dose rate, the reaction time was lengthened. So we must find out the optimal dose rate to promote high oxidation of reactants. The reason why the TOC value of aqueous solution wasn't decreased at the low dose was that there were a lot of low molecular organic acids as an intermediates such as formic acid or glyoxalic acid. In order to use both electron beam accelerator and biological treatment for high concentration refractory organic compounds, biological treatment is needed when low molecular organic compounds exist abundantly in sewage. In this experiment, the condition of making a lot of organic acids is from 5 kGy into 20 kGy dose. Decomposition rate of phenol by electron beam accelerator was first order reaction up to 300ppm phenol solution on the basic of TOC value and also showed first order reaction by using both air and ozone as an oxidants.

• 약학회지
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• 제50권2호
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• pp.84-92
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• 2006

The present study investigated an effect of arsenic trioxide on the urethane-induced lung carcinogenesis in mice. To understand its carcinogenesis, we examined proliferating cell nuclear antigen (PCNA), apoptotic index as well as cell cycle-related proteins (cyclin D1, p21, and p27). Urethane was injected intraperitoneally in ICR mice, and then they were sacrificed at 5, 15, or 25 weeks following treatment of arsenic trioxide. Arsenic trioxide was given with tap water at a concentration of 1 mg/l (low-dose) and 5mg/1 (high-dose) for 25 weeks. During the carcinogenesis, sequential histological changes from hyperplasia to adenomas, and ultimately to overt carcinomas were noted. The development of hyperplasias, adenomas, and carcinomas in the lung were slightly increased by the treatment of low-dose arsenic trioxide. However, there is no correlation between dose and tumor multiplicity. The administration of low-dose arsenic trioxide, significantly increased the tumor size. The proliferative index observed on 5 weeks after significantly increased. Cyclin D1 and p21 protein, cell cycle related proteins, were more significantly increased in hyperplasia and adenoma in low dose arsenic treated group than urethane alone group. The p27 protein expression did not show any significantly changes with arsenic treated or untreated group. Low dose exposure to arsenic trioxide resulted in increased expression of cyclin D1 and p21 protein. The present results indicate that low-dose treatment of arsenic trioxide, but not high dose of it, partly modulate the cellular proliferation, cyclin D1, and p21 protein expression, and that this effect may contribute to accelerated development of lung adenocarcinomas in urethane-induced mice.

• 대한의생명과학회지
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• 제25권1호
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• pp.83-91
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• 2019

This study was undertaken to investigate the therapeutic effect of Angelica acutiloba on allergic dermatitis, which Angelica acutiloba is traditionally known to have antiinflammatory effects. Sprague-Dawley (SD) rats were divided into five groups: normal control group, experimental allergic dermatitis group (vehicle group), low dose of Angelica acutiloba extract (low-dose group), high dose of Angelica acutiloba extract (high-dose group), and antihistamine treated group with experimental dermatitis (antihistamine group). Total leukocyte, neutrophil, lymphocyte, monocyte and eosinophil counts were significantly higher in the vehicle group than in the control group, but these variables were significantly lower in the low- and high-dose groups than in the vehicle group. The platelet/lymphocyte ratio in the red blood cell index was significantly lower in the low- and high-dose groups than in the vehicle group. Low and high doses of the Angelica acutiloba extract did not have toxic effects on liver and kidney. Serum NO, iNOS and levels were highest in the vehicle group but significantly lower in the low- and high-dose groups, especially in the high-dose group. The results of this study suggested that the Angelica acutiloba extract had the effect of alleviating or treating the experimental allergic dermatitis, and it was concluded that the high dose was more effective.

• 대한예방한의학회지
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• 제20권1호
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• pp.145-159
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• 2016

Objectives : The aim was to investigate the characteristics of low dose effect and non monotonic dose responses(NMDRs) and to predict the influence it might have on the health and medicine, traditional Korean medicine. Methods : By investigating recently published major literatures related to low dose effect and NMDRs, the definition, mechanism, major related fields, and the influence on public health and medicine has been categorized and summarized. Results : Although there are still heated debates about the definition of low dose, it implies the biological responses in environmental exposure level and the NDMDRs means the nonlinear relationship between the dose-response in the slope sign change. Also, it implies the new form of the curve showing a U, reverse U shape, and the slop sign constantly changing showing various forms. This mechanism is because the two acceptor shows opposing effects to toxic materials and the affinity is different along with the numerical value that increase and decrease being different. These characteristics generally appear in endocrine disrupters such as bisphenol A, agricultural pesticides, metal, and radiation. The research field in the public health and medical treatment is obesity, problems in metabolism, growth hormone treatment, climacteric treatment, breast cancer, intake of Korean traditional medicine for pregnancy, menopause and phytoestrogen. Conclusions : As a result of discussing implications, NMDRs is a particular effect in low dose and heated debates surround this response, research is being conducted surrounding the field of obesity, problems in metabolism, growth hormone treatment, climacteric treatment, breast cancer, intake of Korean traditional medicine for pregnancy, menopause, and phytoestrogen. More research and interest in needed as it can have a massive influence in the public health and medicine.