• Asian Pacific Journal of Cancer Prevention
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• 제16권11호
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• pp.4543-4548
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• 2015

Background: To investigate the effects of ASMase mediated endothelial cell apoptosis in multiple hypofractionated irradiations in CT26 tumor bearing mice. Materials and Methods: Thirty-five CT26 tumor bearing mice were subjected to single ionizing radiation (IR) of 0, 3, 6, 9, 12, 15, 18 Gy. Eight hours after IR, the mice were sacrificed and tumor tissues were used for CD31 immunohistochemistry staining, TUNEL and CD31 double staining, ASMase activity assay. Then 6 and 12 Gy were chosen for multiple hypofractionated IR experiments according to the above results. Each time after IR, 5 mice were sacrificed and assayed as above. Results: The ASMase activities were increased significantly after a single IR of 12 Gy or higher which was accompanied with remarkable increased endothelial cell apoptosis and decreased MVD. For 6 Gy which was not high enough to trigger ASMase activation, after 2 or more times of IR, the ASMase activities were significantly increased accompanied with remarkable increased endothelial cell apoptosis and decreased MVD. While for 12 Gy, after 2 or more times of IR, the ASMase activities and endothelial cell apoptosis rates were maintained without remarkable increase; however, the MVD was significantly decreased. What's more, the cancer cell apoptosis rates were significantly increased after multiple IR for both 6 Gy and 12 Gy. Conclusions: ASMase mediated endothelial cell apoptosis may play an important role in the process of multiple hypofractionated IR for CT26 colorectal carcinoma.

• Nuclear Engineering and Technology
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• 제52권7호
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• pp.1511-1516
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• 2020

The Korea Research Institute of Standards and Science (KRISS) established a new standard of the absorbed dose to water in LINAC X-ray beams. To confirm the equivalence of the new standard with other national metrology institutes (NMIs), a bilateral comparison study of the absorbed dose to water in high energy X-ray beams was performed between the KRISS and the National Metrology Institute of Japan (NMIJ). The comparison was made in-directly. Three transfer chambers were calibrated in the high energy X-ray beams by both laboratories and the calibration coefficients were compared. The average ratios of the calibration coefficients of the three transfer chambers obtained by the KRISS to those obtained by the NMIJ were 1.004, 1.006, 1.006, 1.007 for 6, 10, 15 and 18 MV X-ray beams, respectively. The calibration coefficients obtained at the KRISS were higher than those at the NMIJ but they were in good agreement within the expanded uncertainty of 1.0% (k = 2). The results of this study will be used as the evidence for the KRISS standard being comparable with those of other NMIs, temporarily, in the interim period up to finalizing a key comparison study, BIPM.RI(I)-K6 managed by the Consultative Committee for Ionizing Radiation.

• 한국전자파학회논문지
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• 제28권12호
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• pp.954-963
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• 2017

본 연구에서는 공진형 무선전력전송시스템에 의해 발생되는 자기장과 전기장 강도 및 이에 의한 인체 내부 전자파 비흡수율(Specific Absorption Rate: SAR) 분포를 분석하였다. 연구에서 사용된 동작주파수는 ISM 대역에 해당하는 6.78 MHz이다. 실제 시스템을 제작하고, 시스템의 송신측에 공급되는 가용 전력을 1 W로 제한하여 전기장 및 자기장 분포를 측정하고, 동일한 규격으로 시뮬레이션한 결과와 비교하였다. 피부, 지방, 근육의 순으로 조직층이 구성된 단순인체모델을 이용하여, WPT 시스템으로부터의 거리에 따른 인체 내부의 유도 전류밀도와 SAR 분포를 구하였다. 측정과 시뮬레이션을 통해 얻어진 전자파 노출 정도를 ICNIRP(International Commission on Non-Ionizing Radiation Protection)의 국제 권고기준과 비교하여 분석하였다.

• 한국방사선학회논문지
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• 제6권2호
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• pp.115-120
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• 2012

레이저 기술의 발전과 더불어 다양한 의료영역에서 레이저가 사용되고 있으며 그로 인한 위험성도 증가하고 있다. 레이저를 안전하게 사용하기 위해서는 레이저의 안전에 관한 지식을 가지고 관리할 수 있는 사람이 지정될 필요가 있다. 이에 따라 많은 나라에서 레이저안전관리자 체제를 운영하고 있다. 의료레이저안전관리자는 레이저의 안전사용과 관련하여 교육과 훈련 등의 권한과 책임을 가진다. 본 연구에서는 의료레이저안전관리자의 미국의 운영현황을 살펴보고 의료레이저안전관리자의 역할과 국내 도입 방안을 살펴보았다.

• Molecules and Cells
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• 제25권2호
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• pp.305-311
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• 2008

After successful clinical application, arginine deiminase (ADI) has been proposed to be a new cancer therapeutic. In the present study, we examined the effect of ADI in combination with ionizing radiation (IR) on MCF-7 cell growth and clonogenic cell death. Cell growth was inhibited by IR in a dose-dependent manner and ADI enhanced the radiosensitivity. ADI itself did not suppress the growth of MCF-7 cells due to the high level of expression of argininosuccinate synthetase (ASS), which convert citrulline, a product of arginine degradation by ADI, to arginine. Previously, it was suggested that ammonia, another product of arginine degradation by ADI, is the main cause of the growth inhibition of irradiated hepatoma cells contaminated with ADI-expressing mycoplasma [van Rijn et al. (2003)]. However, we found that ammonia is not the only factor that enhances radiosensitivity, as enhancement was also observed in the absence of ammonia. In order to identify the enhancing effect, levels of ASS and proteins related to the cell cycle were examined. ASS was unchanged by ADI plus IR, but p21 (a CDK inhibitor) was upregulated and c-Myc downregulated. These findings indicate that changes in the expressions of cell cycle proteins are involved in the enhancement of radiosensitivity by ADI. We suggest that ADI is a potential adjunct to cancer therapy.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.5553-5565
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• 2013

Plants play important roles in human life not only as suppliers of oxygen but also as a fundamental resource to sustain the human race on this earthly plane. Plants also play a major role in our nutrition by converting energy from the sun during photosynthesis. In addition, plants have been used extensively in traditional medicine since time immemorial. Information in the biomedical literature has indicated that many natural herbs have been investigated for their efficacy against lethal irradiation. Pharmacological studies by various groups of investigators have shown that natural herbs possess significant radioprotective activity. In view of the immense medicinal importance of natural product based radioprotective agents, this review aims at compiling all currently available information on radioprotective agents from medicinal plants and herbs, especially the evaluation methods and mechanisms of action. In this review we particularly emphasize on ethnomedicinal uses, botany, phytochemistry, mechanisms of action and toxicology. We also describe modern techniques for evaluating herbal samples as radioprotective agents. The usage of herbal remedies for combating lethal irradiation is a green anti-irradiation approach for the betterment of human beings without high cost, side effects and toxicity.

• Asian Pacific Journal of Cancer Prevention
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• 제13권5호
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• pp.1957-1962
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• 2012

Bladder cancer is a common malignancy worldwide. Despite the increased use of cisplatin-based combination therapy, the outcomes for patients with advanced disease remain poor. Recently, altered activation of the PI3K/Akt/mTOR pathway has been associated with reduced patient survival and advanced stage of bladder cancer, making its upstream or downstream components attractive targets for therapeutic intervention. In the present study, we showed that treatment with DTCM-glutaramide, a piperidine that targets PDK1, results in reduced proliferation, diminished cell migration and G1 arrest in 5637 and T24 bladder carcinoma cells. Conversely, no apoptosis, necrosis or autophagy were detected after treatment, suggesting that reduced cell numbers in vitro are a result of diminished proliferation rather than cell death. Furthermore previous exposure to 10 ${\mu}g/ml$ DTCM-glutarimide sensitized both cell lines to ionizing radiation. Although more studies are needed to corroborate our findings, our results indicate that PDK1 may be useful as a therapeutic target to prevent progression and abnormal tissue dissemination of urothelial carcinomas.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제11권2호
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• pp.11-18
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• 1989

최근의 악관절(TMJ) 방사선학적 진단에 있어 많은 발전과 진단방법이 고안돼어 왔다. 또한 새로운 외과적 술식의 발달로 인하여 악관절내장증(Internal Derangement)의 보다 정확한 진단을 요하게 되었다. 가장 새로운 진단방법으로 핵자기공명촬영법(Magnetic Resonance Imaging:MRI)이 악관절내장증 진단 평가하는데 사용되어지고 있다. 핵자기공명촬영법은 surface coil을 이용하여 관절원판(meniscus)의 비정상적 변화를 효과적으로 진달할 수 있으며, 지금까지 이용되어오던 악관절조영술(arthrography)이나 컴퓨터 단층촬영법(C-T scan)의 단점인, 관절내 조영제 주입이나 방사선 노출둥의 문제점을 배제할 수 있다. 본 연구는 악관절 핵자기공명촬영을 한 92명(184 joints)중 천공(perforation)으로 진단된 31 명 (39 joints)를 대상으로 하였으며, 핵자기공명촬영법의 취약점으로 지적되고 있는 악관절원판 천공 진단의 정확도를 측정하기 위하여 가역적 조사를 통해, 악관절원판 천공으로 진단되어 수술받은 15명(20 joints)에서 65%(13 joints)의 정확성을 확인하였다. 또한 핵자기공명촬영법을 통한 악관절원판 진단의 정확도를 높이기 위하여 condyle head의 퇴행성 변화, articular eminence의 변화, condyle spurring, bone to bone contact등의 경조직 변화와 meniscus의 discontinuity, meniscal deformity, loss of joint space, alternated bilaminar zone 등이 악관절원판 천공진단의 중요한 findings 임을 증명 하였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제15권3호
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• pp.189-197
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• 1993

Tempormandibular Joint pain and dysfunction is a common and important clinical problem. With the recent advances in imaging technology, radiologists have made major contribution to the understanding of TMJ disease. The MRI has several advantages over the conventional imaging methods. It is possible to obtain surprisingly precise images of internal hard and soft tissues with MRI. It is not invasive without ionizing radiation. The abnormal disk position has been thought as the cause of TMJ internal derangement. But there are few methods to relate disk position to TMJ internal derangement quantatively. The object of our study is to determine the amount of anterior displacement fo articular disk in symptomatic patients related each symptoms. Using the method of Dr. Drace, we studied the 38 joints of 22 persons with susceptable TMJ internal derangement. 1. In determining the anterior displacement of TMJ articular disk, the junction between the posterior band and bilaminar zone was useful. 2. The mean anterior displacement of disk in reduction group and without reduction group were $51.0^{\circ}C$ and $81.1^{\circ}C$ respectively. The difference was significant. 3. In the mean anterior displacement of disk, the pain without clicking group showed $84.8^{\circ}C$ and the clicking and pain group $70.8^{\circ}C$, the clicking group respectively.

• 대한방사성의약품학회지
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• 제1권1호
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• pp.23-30
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• 2015

Radioisotopes emitting low-range highly ionizing radiation such as ${\beta}$-particles are of increasing significance in internal radiotherapy. Among the ${\beta}$-particle emitting radioisotopes, $^{67}Cu$ is an attractive radioisotope for various nuclear medicine applications due to its medium energy ${\beta}$-particle, gamma emissions, and 61.83-hour half-life, which can also be used with $^{64}Cu$ for PET imaging. The production and application of the ${\beta}$-emitting radioisotope $^{67}Cu$ for therapeutic radiopharmaceutical are outlined, and different production routes are discussed. A survey of copper chelators used for antibody labeling is provided. It has been produced via proton, alpha, neutron, and gamma irradiations followed by solvent extraction, ion exchange, electrodeposition. Clinical studies using $^{67}Cu$-labelled antibodies in lymphoma, colon carcinoma and bladder cancer patients are reviewed. Widespread use of this isotope for clinical studies and preliminary treatments has been limited by unreliable supplies, cost, and difficulty in obtaining therapeutic quantities.