• 한국방사선학회논문지
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• 제6권6호
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• pp.465-471
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• 2012

본 연구에서는 ALOKA PDM-117(X-ray 측정용 선량계)선량계를 이용하여 구내방사선 촬영기에서 발생하는 방사선에 대하여 거리의 변화에 따른 선량분포를 3차원으로 측정하였다. 구내 방사선촬영에 있어서 XCP 필름 유지기구(XCP-DS FIT)를 사용하여 영상을 얻는 경우 방사선의 선량 분포는 변할 수 있고 이것은 방사선영상과 환자피폭에 영향을 미치게 된다. 따라서 위치에 따른 선량을 표준화하여 XCP 필름 유지기구 사용 유무에 따른 선량과의 관계를 알아볼 필요성이 있다. 본 연구에서는 측정된 3차원 선량분포를 통하여 등각촬영시 얻을 수 있는 최적의 영상과 동일한 선량을 얻기 위한 조사시간과 거리와의 관계 및 선량분포의 모서리 퍼짐 현상에 대한 결과를 정량적으로 측정하였다. 거리가 증가함에 따라 중심 선량은 감소하였지만 조사통 가장자리 부분의 방사선 퍼짐은 증가하는 경향을 보였다. 이것은 XCP 필름 유지기구를 사용하는 경우에 선속 가장자리 부분에서 방사선의 선량이 퍼지는 경향을 보이기 때문이므로 환자의 병소이외의 부분에 대한 피폭에 주의를 기울여야 함을 정량적으로 확인 하였다. 본 연구의 결과는 품질 좋은 치아영상을 얻고, 환자의 피폭선량을 줄이는데 매우 유용하게 사용되어 질 수 있을 것으로 사료된다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권1호
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• pp.319-323
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• 2012

Objective: To explore the feasibility of shrinking field technique after 40 Gy radiation through 18F-FDG PET/CT during treatment for patients with stage III non-small cell lung cancer (NSCLC). Methods: In 66 consecutive patients with local-advanced NSCLC, 18F-FDG PET/CT scanning was performed prior to treatment and repeated after 40 Gy. Conventionally fractionated IMRT or CRT plans to a median total dose of 66Gy (range, 60-78Gy) were generated. The target volumes were delineated in composite images of CT and PET. Plan 1 was designed for 40 Gy to the initial planning target volume (PTV) with a subsequent 20-28 Gy-boost to the shrunken PTV. Plan 2 was delivering the same dose to the initial PTV without shrinking field. Accumulated doses of normal tissues were calculated using deformable image registration during the treatment course. Results: The median GTV and PTV reduction were 35% and 30% after 40 Gy treatment. Target volume reduction was correlated with chemotherapy and sex. In plan 2, delivering the same dose to the initial PTV could have only been achieved in 10 (15.2%) patients. Significant differences (p<0.05) were observed regarding doses to the lung, spinal cord, esophagus and heart. Conclusions: Radiotherapy adaptive to tumor shrinkage determined by repeated 18F-FDG PET/CT after 40 Gy during treatment course might be feasible to spare more normal tissues, and has the potential to allow dose escalation and increased local control.

• Asian Pacific Journal of Cancer Prevention
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• 제15권17호
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• pp.7129-7135
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• 2014

Background: In this study, we aimed to evaluate the growth inhibitory effect of the combination of ethaselen (BBSKE) and low fixed dose of selenite against A549 human non-small cell lung cancer cells in vitro. Materials and Methods: Growth inhibitory effects against A549 cells were determined by SRB assay. Combination index (CI) values were calculated based on Chou-Talalay median-effect analyses. Dose reduction index (DRI) values were applied to calculate dose reduction of selenite. Contents of free thiols and GSH were determined by DTNB assay and intracellular ROS levels by DCFH-DA fluorescence labeling. Results: Compared with BBSKE or selenite single treatment, the combined application of ethaselen and a low fixed dose of selenite shortened the onset time of sodium selenite, reduced $IC_{50}$ values, and increased the maximum inhibition rates, suggesting a possible molecular mechanism of the synergism. Obvious synergistic effects were observed after different times of combination treatment, especially after 24 h. Compared with selenite single treatment, dosage of selenite could be remarkably reduced in combination therapy to gain the same inhibitory effect on cell proliferation. Compared with BBSKE single treatment, the content of free thiols and GSH were significantly reduced and ROS levels greatly elevated in the combination group. For the combination treatment, cell viability increased as greater concentrations of GSH were added. Conclusions: All these results indicate that the combination treatment of BBSKE and selenite showed synergism to inhibit A549 cell proliferation in vitro, and also reduced the selenite dosage to mitigate its toxicity which is very meaningful for combination chemotherapy of lung cancer. The synergism was probably caused by the accelerated exhaustion of intracellular reductive substances, such as free thiols and GSH, which ultimately leads to enhanced oxidative stress and apoptosis.

• 한국식품과학회지
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• 제7권3호
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• pp.148-153
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• 1975

국내의 변질미(變質米)에서 분리, 동정된 7종의 독소생성(毒素生成)곰팡이 Aspergillus clavatus, Asp. flavus var. columnaris, Asp. fumigatus, Asp. ochraceus, Penicillium citrinum, Pen. implicatum 및 Pen. islandicum의 코발트-60 감마선에 대한 감수성(感受性)을 조사하여 다음과 같은 결과를 얻었다. 공시(共試)한 모든 곰팡이의 분생포자(分生胞子)에 대한 생존곡선(生存曲線)은 S자형을 나타냈으며 11.56 krad/min의 선량율(線量率)에서 $D_{10}$값은 $14{\sim}33$ krad, 유도선량(誘導線量)은 $12{\sim}56$ krad, 200 krad 에서의 불활성화계수(不活性化係數)는 $4.6{\sim}12.8$이었다. Asp. flavus와 Pen. islandicum분생포자(分生胞子)의 방사선(放射線) 감수성(感受性)에 미치는 선량율(線量率)의 영향을 보면 고선량율(高線量率)(11.56 krad/min)은 저선량율(低線量率)(2.67 krad/min)보다 $D_{10}$값의 감소를 가져왔다.

• 대한방사선기술학회지:방사선기술과학
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• 제44권1호
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• pp.39-46
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• 2021

This study confirmed the usefulness of the copper filter according to the mode change by comparing and analyzing the energy change according to the application of the copper filter and the change in effective dose and image quality according to the distance to the subject in the DR(Digital Radiography) system. The average energy increased when the copper filter was applied and the reduction rate by 50% of mAs was increased as the thickness of the copper filter increased according to the application of the 10 kVp rule in AEC mode. The effective dose decreased as the thickness increased when the copper filter was applied in AEC(Automatic Exposure Control) mode and manual mode according to the application of the 10 kVp rule, and the decrease rate decreased with increasing 10 kVp increments. As a result of analyzing the dicom images for AEC mode and manual mode with Image J. the PSNR(Peak Signal to Noise Ratio) values were approximate values of less than 30 dB for each mode and for each copper filter thickness. When the copper filter was applied, the average energy increased, so when the 10 kVp rule was applied, the mAs for each mode could be reduced, and the effective dose could also be reduced. However, as the distance and tube voltage increased, the reduction rate of mAs decreased, and the quality of the image was found to decrease when the copper filter was applied, but there was no difference in quality of the image when the copper filter thickness increased.

• 대한방사선기술학회지:방사선기술과학
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• 제15권1호
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• pp.79-87
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• 1992

It is a matter of common knowledge that madical radiation is most accented for of radiation is doses applied to the whole of people, and of them the radation dose by radiography diagnosis is mainly prevalent. In applying X-rays to a certain man for radiography diagnosis a radiologyist will have to have an absolute sense of mission concerning the reduction and prevention of the patient's radiation dose as the radiologyist obligation. Accordingly, the radiography conditions of the patient's chest employed 197 medical facilites were surveyed and skin dose was computated by the IPH Bit system and examined. As a result, it was shown that the average skin dose was $288\;{\mu}Sv$, its minimum value was $1600\;{\mu}Sv$, which was over 32 times its minimum value. This shows that the appropriate radiography method has not been applied at applying X-ray to the patient. It comes from the performance of X-ray equipment, the choice of auxiliary equipment materials etc. But the most important thing is to master the appropriate radiography condition, and therefore this point will have to be kept in mind.

• 한국안전학회지
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• 제8권4호
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• pp.165-174
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• 1993

For the safety assessment of the demonstration-scale incineration plant for treating the combustible radioactive wastes, radiation doses of a worker and a residential individual were estimated. The demonstration plant showed a good performance of trial-burn tests using non-radioactive tracers with resulting In high mass reduction of around 40 times and very low emmission of dusts through a stack, which promised a high decontamination factor in an order of 10$^{7}$ . Based on the result s obtained from the trial-burns in the process, the estimation of radiation dose for workers and general publics near the plant was made using dose pathway calculation theories. The parametric values for calculation were selected from design and operational results of the process and from more conservative conditions In reference data. The estimated annual doses for workers and residential indivisuals were 3.07 $\times$ 10$^{-4}$ and 4.35 X 10$^{-8}$ $\mu$Sv/y, respectively, which were high enough to operate the process when comparing with the allowable dose limit in the regulation. The dose calculation models were quite applicable with showing an excellent safety for the process.

• 한국임상수의학회지
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• 제34권1호
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• pp.18-22
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• 2017

The aim of this study was to prove that the hypothesis of half dose (HD) allergen-specific immunotherapy (ASIT) in the treatment of canine atopic dermatitis (CAD) would result in a similar success rate compared to the standard dose (SD) ASIT. Clinical signs were evaluated using a third version of the Canine Atopic Dermatitis Extent and Severity Index (CADESI-03) prior to ASIT (day 0), at the end of induction (day 43), and at three month afterwards (day 90). Of the 18 atopic dogs, 12 dogs (SD group: 6; HD group: 6) had a good - excellent response to the house dust mites-specific immunotherapy. The efficacies of ASIT were 66.6% in both groups. The grades of reduction rate CADESI-03 were not different between two groups. Therefore, half dose protocol of house dust mites-specific immunotherapy is an effective and efficient method to treat CAD.

• 인간식물환경학회지
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• 제23권2호
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• pp.171-178
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• 2020

The present study was conducted to determine the effects of electron beam irradiation on the postharvest quality of cut flowers. Cut flowers were irradiated with electron beam at 100, 200, 400, 600, 800, 1,000, and 2,000 Gy with a 10 MeV linear electron beam accelerator to evaluate their irradiation tolerance. Postharvest quality was determined by monitoring fresh weight loss, flower longevity, flower diameter, flowering rate, visual quality of flowers and leaves, and chlorophyll content. Cut flowers showed a radiation-induced damage with increasing the irradiation dose. Flower longevity and fresh weight of cut flowers decreased when the irradiation dose was increased. Flower bud opening was also inhibited in a dose-dependent manner. The effective irradiation doses for 10% reduction of postharvest quality (ED₁₀) values were 144.4, 451.6, and 841.2 Gy in the 'Medusa' lily, 'Montezuma' carnation, and 'Rosina White' eustoma, respectively. Although tolerance of cut flowers to electron beam irradiation vary according to species, cultivars, or maturity stage conditions, it is conceivable that 'Montezuma' carnation and 'Rosina White' eustoma could be tolerated and maintained overall postharvest quality up to 400 Gy, the generic irradiation dose approved by the Animal and Plant Health Inspection Service (APHIS) and the International Plant Protection Convention (IPPC) for postharvest phytosanitary treatments.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.284.3-285
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• 2002

Paraquat(methyl viologen) is a bis-quaternary ammonium compound as a wide range herbicide. which was first introduced as an oxidation-reduction indicator dye. When paraquat(fatal dose. 1-2g) was administered to men, the oxido-reduction system of cell was repeatedly acted to perpetuate the cell membrane system, Many death cases had been occurred after ingestion of paraquat around Daejon area for the last six months. (omitted)