• 한국의학물리학회지:의학물리
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• 제32권2호
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• pp.50-58
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• 2021

Purpose: In this study, we investigated the relationship between the noise characteristics and the number of projected images in tomosynthesis using a digital phantom. Methods: The digital phantom consisted of a columnar phantom in the center of the image and a spherical phantom with a diameter of 80 pixels. A virtual scan was performed, and 128 projected images (Tomo_w/o) of the phantoms were obtained. The image noise according to the Poisson distribution was added to the projected images (Tomo_×1). Furthermore, another projected image with additional noise was prepared (Tomo_×1/2). For each dataset, we created datasets with 64 (half) and 32 (quarter) projections by removing the even-numbered images twice from the 128 (fully) projected images. Tomosynthesis images were reconstructed by filtered back projection (FBP). The modulation transfer function (MTF) was estimated using the sphere method, and the noise power spectrum (NPS) was estimated using the two-dimensional Fourier transform method. Results: The MTFs did not change between datasets, and the NPSs improved as the number of projected images increased. The noise characteristics of the Tomo_×1_half images were the same as those of the Tomo_×1/2_full. Conclusions: To achieve a reduction in the patient dose in tomosynthesis acquisition, we recommend reducing the number of projected images rather than reducing the dose per projection.

• Journal of Medicine and Life Science
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• 제20권2호
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• pp.89-93
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• 2023

We present three cases of patients with breast cancer and psoriasis who received radiotherapy following breast-conserving surgery. One patient developed an extensive flare-up of psoriasis during chemotherapy. After discontinuing chemotherapy, she received conventional radiotherapy to the ipsilateral whole breast, axillary, and supraclavicular lymph nodes with 50.4 Gy in 28 fractions and boosted with 10 Gy in five fractions to the tumor bed. Two patients received hypofractionated whole-breast radiotherapy at a total dose of 40.05-42.4 Gy in 15-16 fractions. In all three cases, there was no flare-up of psoriatic events at least 6 months after the completion of radiotherapy. We hypothesized that there is a close relationship between psoriatic events and the extent of trauma rather than the daily dose of the fraction. Therefore, we confirmed that the effect of radiotherapy on psoriatic events is minimal if the radiation field size does not exceed that of the whole breast.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4096-4101
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• 2023

Radon is a radioactive gas produced from the uranium-238 series. Radon gas affects public health and is the second cause of lung cancer. The study samples were collected from one area of the city of Jazan, southwest of the Kingdom of Saudi Arabia. The influence of engineering and physical parameters on the emanation coefficient of gas and other gas parameters was studied. Parameters for radon were measured using a CR-39 Solid-State Nuclear Track Detector (SSNTD) through a sealed emission container. The results showed that the emanation coefficient was affected directly by the change in the grain size of the soil. All parameters of measured radon gas have the same behavior as the emanation coefficient. The relationship between particle size and emanation coefficient showed a good correlation. The values of the emanation coefficient were inversely affected by the mass of the sample, and the rest of the parameters showed an inverse behavior. The results showed that increasing the volume of the container increases the accumulation of radon sons on the wall of the container, which increases the emission factor. The rest of the parameters of radon gas showed an inverse behavior with increasing container size. The results concluded that changing the engineering and physical parameters has a significant impact on both the emanation coefficient and all radon parameters. The emanation coefficient affects the values of the radiation dose of an alpha particle.

• Journal of Yeungnam Medical Science
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• 제6권2호
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• pp.121-125
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• 1989

1986년 4월부터 1988년 12월까지 영남대학병원 치료 방사선과에 폐암으로 확진후 등록된 환자중 기관지정 검사상 지도 폐쇄의 소견이 있으며 흉부 X-선 사진상 현저한 폐음영이 있었던 환자 21명에 대한 방사선 치료 성적은 다음과 같다. 1. 71.4%의 환자(15/21)에서 임상 증상의 호전을 보였다. 2. 소세포성 암환자는 30GY/10 fractions의 선량에서도 100%의 증상 호전 및 흉부 X-선상 소견의 호전을 보였다. 3. 비소세포성 암환자에서 50GY이상 조사군 이 45GY이하 조사군 보다 우수한 성적을 보였다. 4. 병변의 위치와 무기폐의 호전정도는 무관하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제4권1호
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• pp.25-31
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• 2000

ATP-sensitive potassium channels ($K_{ATP}$ channels) play an important role in insulin secretion from pancreatic beta cells. We have investigated the effect of propofol on $K_{ATP}$ channels in cultured single pancreatic beta cells of rats. Channel activity was recorded from membrane patches using the patch-clamp technique. In the inside-out configuration bath-applied propofol inhibited the $K_{ATP}$ channel activities in a dose-dependent manner. The half-maximal inhibition dose (ED50) was $48.6{\pm}8.4\;{\mu}M$ and the Hill coefficient was $0.73{\pm}0.11.$ Single channel conductance calculated from the slope of the relationship between single channel current and pipette potential $(+20{\sim}+100\;mV)$ was not significantly altered by propofol $(control:\;60.0{\pm}2.7\;pS,\;0.1\;mM\;propofol:\;58.7{\pm}3.5\;pS).$ However, mean closed time was surely increased. Above results indicate that propofol blocks the $K_{ATP}$ channels in the pancreatic beta cells in the range of its blood concentrations during anesthesia, suggesting a possible effect on insulin secretion and blood glucose level.

• 한국환경성돌연변이발암원학회지
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• 제22권3호
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• pp.187-198
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• 2002

Chlorpyrifos is an organophosphate insecticide and one of the most commonly and widely used insecticide. However, a little known about the dermal risk of chlorpyrifos on human being. Therefore, this study was conducted for the dermal risk assessment after exposure to chlorpyrifos in Korean farmers. First, skin irritation by chlorpyrifos (10 mg/$\textrm{cm}^2$, 50 mg/$\textrm{cm}^2$, 100 mg/$\textrm{cm}^2$, 250 mg/$\textrm{cm}^2$ in acetone) was determined in rabbits for 5 days considering the usage of chlorpyrifos short term highly exposure. The index of skin irritation by chlorpyrifos was increased in each dose and length of exposure dependent manners. Next, using benchmark dose (BMD$_{5}$) approach, the dose-response relationship was assessed to calculate the reference dose (RfD). The value of RfD was 2.84 $\mu\textrm{g}$/kg/day from 142.16 $\mu\textrm{g}$/kg/day BMD5 value divided uncertainty factor 50. Finally, we assessed human dermal risk of chlorpyrifos with exposure level and RfD. Skin absorbed levels were assumed with several exposure scenarios encounting the circumstances of exposure that application method, protection equipment and cloth, exposure time and exposure frequency during chlorpyrifos spraying. By the comparison of skin absorbed dose with the reference dose, it was identified that risk values (risk index) to skin chlorpyrifos exposure were 0.958 from the point of above results and it was recommended that the occurrence of hazard effect (skin irritation toxicity) of chlorpyrifos would not be expected. Risk index was smaller than 1 in the case of spraying vehicle mounted application, 1hour exposure time and wearing protective cloth exposure. Whereas, risk index was above 1 in the case of hand-held application, 2hour exposure time and wearing common cloth. Comparing two kinds of application method, total risk index of the hand held application (1.67) was higher than vehicle mounted (0.27). Therefore, chlorpyrifos skin exposure was mainly affected by application equipment and applied form. The results of risk assessment on the human dermal toxicity of chlorpyrifos should be required to control in keeping safety rules, skin surface area available for contact, spraying time ,and spraying frequency.y.

• Radiation Oncology Journal
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• 제10권2호
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• pp.237-245
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• 1992

1979년부터 1986년까지 자궁경부암으로 진단되어 외부방사선 및 강내 방사선 치료를 함께 받은 550명의 환자를 대상으로 직장 합병증과 방사선량에 대한 후향적 분석을 시행하였다. 전체 환자550명 중 468명은 근치적 목적으로 방사선 치료를 받았으며, 82명은 수술후에 추가적인 방사선 치료를 받았다. 이들 82명 중 43명은 수술절제연 양성으로, 31명은 원발질환의 재발로, 8명은 stump cancer로 방사선 치료를 받았다. Grade 2와 3를 포함하는 직장 합병증의 발생률은 5년에 $6.7였다. 합병증이 생긴 환자군의 직장에 조사된 방사선량은 $7424{\pm}834$ cGy이었으며, 이는 합병증이 발생하지 않은 환자군의 $6946{\pm}717$ cGy보다 많았고 통계학적 유의성이 있었다(p<0.05) 직장합병증의 정도에 따른 방사선량의 차이는 통계학적 유의성이 없었다(p>0.05). 전체 합병증의 발생률은 직장에 조사된 방사선량에 따라 증가하였는데, 6,500 cGy 이하에서는 5년 합병증 발생률이 15.6이었으며 8,000 cGy 이 상 조사된 환자군에서는 71.2이었다. 직장 합병증에 영향을 줄 수 있는 요인들을 Cox의 방법에 의해 다변량분석한 결과 당뇨가 있는 경우 합병증 발생률이 증가하였으며, 강내 방사선치료는 한번 시행한 경우보다 두번 시행한 환자군에서 합병증 발생률이 더 적었다. 또한 자궁의 후방만곡은 ovoid의 크기와 함께 분석된 경우에 통계적으로 중요한 의미를 나타내었고, ovoid의 크기는 이번 분석에서 합병증 발생에 가장 중요한 인자로 나타났다. 직장에 조사된 방사선량도 중요한 요소로서 방사선량이 많아질수록 합병증 발생률은 증가하였다(p<0.05). TDF와 CRE단위로 분석하였으며 선량과 합병증의 관계는 cGy 단위의 결과와 같았다.

• 융합정보논문지
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• 제8권2호
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• pp.219-225
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• 2018

본 연구의 목적은 개방형 정보 혁신을 기술 흡수형 혁신과 기술 활용형 혁신으로 나누어 전략적 제휴 요인과 통합하여 수출성과에 미치는 영향을 분석하는데 있다. 본 연구는 구조방정식모형의 PLS(Partial Least Square)를 사용하여 개방형정보 혁신과 전략적 제휴, 수출성과의 관계에서 조직문화의 조절효과를 설정한 6개의 가설을 201개 표본으로 실증분석 했다. 분석 결과 개방형 정보 혁신 중 기술 흡수형 혁신은 전략적 제휴에 영향을 미치지 못했다. 반면 기술활용형 혁신은 전략적 제휴에 긍정적 영향을 주었다. 전략적 제휴는 또한 수출성과에 긍정적 영향이 있는 것으로 나타났다. 조절효과 분석 결과 조직문화와 기술 흡수형 혁신의 상호작용은 전략적 제휴에 긍정적 영향을 주었다. 또한, 조직문화와 기술 활용형 혁신의 조절효과도 전략적 제휴에 유의한 영향을 보였다. 그러나 조직문화와 전략적 제휴의 조절효과는 수출성과에 영향을 미치지 못하였다. 본 연구는 조직문화의 조절효과를 분석한 점에서 기여도가 있다. 향후에는 개방형 정보 혁신과 외부요인의 통합분석이 필요하다.

• 대한예방한의학회지
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• 제5권1호
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• pp.31-40
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• 2001

Legal permissible limit of herbal drugs metal level in Korea is define 'less 30.0ppm in total(except mineral drugs)' including Pb Hg Cd As Cr Ni etc. This limit has a lot of problems in several factors, that is, not divide hazard and essential elements, not consider high and low toxic effect in each metal, not calculate dose-response relationship and average health behavior in Korean etc. As a that result, It has strong limits and weakness in the basic toxicology and Oriental medicine. To improve and correct these factors, We need to several new approach as like below. It must be radical study following problems in short and middle-long period in the future, toxic metal and essential element must be divide to basic toxicology and also be diverse toxic effect. But mineral drugs that included a amount of severe toxic metals is being used as active prescription drug until now. If toxic, safety and side-effect of metals will be considered, mineral drugs must prohibit instantly or use at least after examined toxic effect. But one of the most important things about herbal drugs contamination, all people and department (government, farmer and trader, oriental medicine doctors and association) will be participate cooperative and collection for preventive or the least contamination in herbal drugs.

• 한국물환경학회지
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• 제26권6호
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• pp.1028-1033
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• 2010

Wastewater reuse for agricultural irrigation needs treatment and control of pathogens to minimize risks to human health and the environment. In order to evaluate the water quality of UV-treated reclaimed water, this study focused on the relationship between micro-pathogens and particulate matters. MS2 was selected as an index organism because it has similar characteristics to human enteric virus and strong resistance to UV disinfection. The turbidity and suspended solid (SS) were selected for test parameters. In this study, it was performed with different UV doses (30 and $60mJ/cm^2$) for estimation of the MS2 inactivation rate using collimated beam batch experiments in the laboratory. The experiment results by turbidity or SS concentration presented that the increased concentration of them lowered MS2 inactivation. At the turbidity (below 4.27 NTU) and SS (below 1.47 mg/L) of the low level range, the inactivation of 60 UV dose is higher than 30 UV dose. However, at the turbidity and SS of the high level, the increasing UV dose did not show apparent increasing the MS2 inactivation. In quantitative microbial risk assessment (QMRA), it can confirm the trend that $P_D$ and turbidity concentrations have positive correlationship at the low concentration, which was also observed in SS. The QMRA can be helpful in communication with public for safe wastewater reuse and be recommended.