• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1999년도 춘계학술대회
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• pp.53-61
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• 1999

Radiation therapy has been used for the cancer treatment and radiation synovectomy$\^$1-3)/. There are two kinds of radiation therapy; the external radiation therapy and the internal radiation therapy. Hitherto, the external radiation therapy has been widely used, but for the lack of its selectivity it requires strong radiation dose and causes the irritation and damage of the normal tissue or organ. Therefore many researchers give their interests to the internal radiation therapy in which the radioactive materials are injected directly into the target organ or tissue. Many ${\beta}$-emitting radionuclides have been studied for the application of the internal radiation theraily. Among them, Holmium-166 has the many beneficial physical characteristics for the internal radiation therapy such as appropriate half life (26.8hr), high ${\beta}$ energy (max. 1.85 MeV(51%), 1.77 MeV (48%), mean 0.67MeV), and low ${\gamma}$ energy (0.081MeV) easily detected by ${\gamma}$-camera. In the internal radiation therapy, the administered radioactive materials should be retained in the target long enough to increase the therapeutic effects and avoid the damage in the normal tissue or organ. For this purpose, radionuclides are used as complex form with carriers. Carriers should have a high affinity with radionuclides in vivo and in vitro, so the complex can be evenly distributed in the lesion but can not be leaked out from the lesion.

• 치과방사선
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• 제25권2호
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• pp.309-318
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• 1995

In head and neck region, the critical organ and tissue doses were determined, and the risks were estimated from lateral, posteroanterial and basilar cephalometric radiography. For each cephalometric radiography, 31 TLDs were placed in selected sites(18 internal and 13 external sites) in a tissue-equivalent phantom and exposed, then read-out in the TLD reader. The results were as follows: 1. From lateral cephalometric radiography, the highest effective dose recorded was that delivered to the salivary gland(3.6pSv) and the next highest dose was that received by the bone marrow(3pSv). 2. From posteroanterial cephalometric radiography, the highest effective dose recorded was that delivered to the salivary gland(2pSv) and the next highest dose was that received by the bone marrow(1.8pSv). 3. From basilar cephalometric radiography, the highest effective dose recorded was that delivered to the thyroid gland(31A p Sv) and the next highest dose was that received by the salivary gland(13.3 p Sv). 4. The probabilities of stochastic effect from lateral, posteroanterial and basilar cephalometric radiography were $0.72{\times}10^{-6}$, $0.49{\times}10^{-6}$ and $3.51{\times}10^{-6}$, respectively

• Journal of Preventive Medicine and Public Health
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• 제26권2호
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• pp.231-250
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• 1993

Thirty five male Sprague-Dawley rats were treated with cadmium chloride solution ranging from 0.2 to 3.2mg $CdCl_2/kg$ by intravenous single injection. At 48 hours after administration of cadmium, total cadmium, MT bound cadmium and histopathologic finding in liver, kidney, lung, heart, testis, metallothionein in liver, kidney and total cadmium in bleed were examined. Tissue cadmium concentration was highest in liver, followed by in kidney, heart, lung and testis. Cadmium bound to rnetallothionein (MT-Cd) and ratio of MT-Cd to total cadmium were increased in liver and kidney dependently of cadmium exposure dose, but not significantly changed in other organs. On histopathologic finding, the most susceptible organ was heart in considering cadmium exposed dose, but testis in considering cadmium concentration. Blood cadmium concentration was increased with dose-dependent pattern, and significantly correlated with tissue cadmium concentration, so that we may estimate tissue cadmium concentration by measurement of blood cadmium concentration. Metallothionein in liver and kidney was increased with dose-dependent pattern, higher in liver than in kidney, and was significantly correlated with tissue cadmium concentration. However, metallothionein induction efficiency of tissue cadmium(${\mu}g\;MT/{\mu}g\;Cd$) was eater in liver than in kidney, and reverse to tissue concentration or exposed dose of cadmium.

• 대한방사선기술학회지:방사선기술과학
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• 제38권1호
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• pp.17-21
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• 2015

소아백혈병의 치료방법 인 조혈모세포이식법의 전처치 방법으로서 항암제와 함께 대표적으로 사용되고 있는 전신방사선조사에 대하여 치료를 시행하기 전 정량적인 인체장기에 대한 선량을 평가하고자 하였다. 모의실험 프로그램 MCNPX를 사용하여 가상의 공간에서 소아용 모의피폭체를 대상으로 조직보상체의 재질을 변화시켜 실험을 진행하였다. 그 결과 첫째, 평균피부선량은 조직보상체의 재질에 따라 Plexiglass는 74.60 mGy/min, Al은 73.96 mGy/min, Cu는 72.26 mGy/min, Pb의 경우 67.90 mGy/min을 보였다. 둘째, 심부선량은 조직보상체 재질에 상관없이 갑상선, 생식선, 소화기계, 머리, 폐, 신장의 순으로 높게 나타났다. 끝으로 조직보상체와 환자와의 거리는 50 cm 이격시켰을 때가 이상적인 것으로 분석되었다. 본 연구결과를 토대로 할 때, 조직보상체 Al, Cu, Pb은 현재 사용되고 있는 Plexiglass 재질을 대체할 수 있을 것으로 판단된다.

• Journal of Chest Surgery
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• 제51권5호
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• pp.328-332
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• 2018

Background: Extracorporeal life support (ECLS) can be applied in brain-dead donors for organ perfusion before donation, thereby expanding the donor pool. The aim of this study was to examine the benefits and early clinical outcomes of ECLS for organ preservation. Methods: Between June 2012 and April 2017, 9 patients received ECLS with therapeutic intent or for organ preservation. The following data were collected: demographics, purpose and duration of ECLS, cause of death, dose of vasoactive drugs, and need for temporary dialysis before organ retrieval. The early clinical outcomes of recipients were studied, as well as survival and graft function at 1 month. Results: ECLS was initiated for extracorporeal cardiopulmonary resuscitation in 5 patients. The other patients needed ECLS due to hemodynamic deterioration during the assessment of brain death. We successfully retrieved 18 kidneys, 7 livers, and 1 heart from 9 donors. All organs were transplanted and none were discarded. Only 1 case of delayed kidney graft function was noted, and all 26 recipients were discharged without any significant complications. Conclusion: The benefits of protecting the vital organs of donors is significant, and ECLS for organ preservation can be widely used in the transplantation field.

• 대한디지털의료영상학회논문지
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• 제14권2호
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• pp.23-31
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• 2012

There are AEC mode and fix mode to exposure when the whole spine antero-posterior radiography is done by using DR equipment. This study compared the utility of fix mode to AEC mode, by evaluating organ dose and effective dose and by examining the quality of radiographic image. GE DEFINIUM 8000 and ART-200X Rando Phantom manufactured by Flukebiometical were used for this study. The Rando phantom was set in front of wall detector of X-rays equipment. AEC mode was set at 80kVp and Fix mode was set at 80kVp, 25mAs, 32mAs, 40mAs, and 50mAs. Whole spine AP image were aquired by combining C, T-L and L-S spine images obtained through 3 exposures. When obtaining C, T-L and L-S spine images, were checked for Air kerma (mGy) value calculated by UNFORS Xi meter attached at the phantom surface of center of radiation field. The effective and organ doses were compared by PCXMC program (PC-Based Monte Carlo Program). The quality of obtained radiographic image was evaluated visually by 3 radiologists using resolution chart. When the effective doses was calculated based on tissue weighting factor of ICRP-103, 1.278mSv was measured by AEC mode, and Fix mode measured 0.405mSv at 25mAs, 0.518mSv at 32mAs, 0.649mSv at 40mAs, and 0.810mSv at 50mAS. In addition, the organ dose measured with esposure at 25mAs by Fix mode was almost equivalent to the organ dose by AEC mode, at the esophagus, thyroid, oral mucosa, salivaly glands located at the cervical spine part, while the organ dose by Fix mode was in general lower than the organ dose by AEC mode at the other organs. When Fix mode at 32mAs, 40mAs, and 50mAs was compared to AEC mode for organ dose in 26 organs, AEC mode had higher measurement in 21 organs but not for than brain, trachea, thyroid, oral mucosa, and salivaly glands which are located at the cervical spine part. The image quality evaluated by resolution test chart was much higher with AEC mode than the quality with Fix mode at all exposure conditions. However, while the image quality of cervical spine exposured at 50mAs by Fix mode was lower than the quality of AEC mode, thoraco-lumbar spine and lumbo-sacral spine were calculated and the quality was similar to AEC mode. Scoliosis occurs mainly at thoraco-lumbar and lumbo-sacral spine, not at cervical spine. Compared to AEC mode, Using the appropriate protocol (80kVp, 50mAs) of fix mode for whole spine AP radiography was thought to be useful because the image quality of the thoraco-lumar and lumbo-sacral spine was similar on AEC mode, Also organ and effective doses can be decreased with Fix mode. Therefore, It is considered that fix mode can be used properly with AEC mode for whole spine AP radiography when considering patient's body posture.

• Radiation Oncology Journal
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• 제36권3호
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• pp.172-181
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• 2018

Successful anticancer strategies require a differential response between tumor and normal tissue (i.e., a therapeutic ratio). In fact, improving the effectiveness of a cancer therapeutic is of no clinical value in the absence of a significant increase in the differential response between tumor and normal tissue. Although radiation dose escalation with the use of intensity modulated radiation therapy has permitted the maximum tolerable dose for most locally advanced cancers, improvements in tumor control without damaging normal adjacent tissues are needed. As a means of increasing the therapeutic ratio, several new approaches are under development. Drugs targeting signal transduction pathways in cancer progression and more recently, immunotherapeutics targeting specific immune cell subsets have entered the clinic with promising early results. Radiobiological research is underway to address pressing questions as to the dose per fraction, irradiated tumor volume and time sequence of the drug administration. To exploit these exciting novel strategies, a better understanding is needed of the cellular and molecular pathways responsible for both cancer and normal tissue and organ response, including the role of radiation-induced accelerated senescence. This review will highlight the current understanding of promising biologically targeted therapies to enhance the radiation therapeutic ratio.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.86-89
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• 2002

The purpose is to develop a system to reduce the organ movement from the respiration during the 3DCRT or IMRT. This research reports the experience of utilizing personally developed system for mobile tumors. The patients clinical database was structured for 10 mobile tumors and patient setup error measurement and immobilization device effects were investigated. The RMRD system is composed of the respiratory motion reduction device utilized in prone position and abdominal strip device(ASD) utilized in the supine position, and the analysis program, which enables the analysis on patients setup reproducibility. Dose to normal tissue between patients with RMRDs and without RMRDs was analyzed by comparing the normal tissue volume, field margins and dose volume histogram(DVH) using fluoroscopy and CT images. And, reproducibility of patients setup verify by utilization of digital images. When patients breathed freely, average movement of diaphragm was 1.2 cm in prone position in contrast to 1.6 cm in supine position. In prone position, difference in diaphragm movement with and without RMRDs was 0.5 cm and 1.2 cm, respectively, showing that PTV margins could be reduced to as much as 0.7 cm. With RMRDs, volume of the irradiated normal tissue (lung, liver) reduced up to 20 % in DVH analysis. Also by obtaining the digital image, reproducibility of patients setup verify by visualization using the real-time image acquisition, leading to practical utilization of our software. Internal organ motion due to breathing can be reduced using RMRDs, which is simple and easy to use in clinical setting. It can reduce the organ motion-related PTV margin, thereby decrease volume of the irradiated normal tissue.

• 대한방사선기술학회지:방사선기술과학
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• 제43권6호
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• pp.443-451
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• 2020

This study is to evaluate absorbed dose from right lung for brachytherapy and to estimate the effects of tissue heterogeneities on dose distribution for Iridium-192 source using Monte Carlo simulation. The study employed Geant4 code as Monte Carlo simulation to calculate the dosimetry parameters. The dose distribution of Iridium-192 source in solid water equivalent phantom including aluminium plate or steel plate inserted was calculated and compared with the measured dose by the ion chamber at various distances. And the simulation was used to evaluate the dose of gamma radiation absorbed in the lung organ and other organs around it. The dose distribution embedded in right lung was calculated due to the presence of heart, thymus, spine, stomach as well as left lung. The geometry of the human body was made up of adult male MIRD type of the computational human phantom. The dosimetric characteristics obtained for aluminium plate inserted were in good agreement with experimental results within 4%. The simulation results of steel plate inserted agreed well with a maximum difference 2.75%. Target organ considered to receive a dose of 100%, the surrounding organs were left the left lung of 3.93%, heart of 10.04%, thymus of 11.19%, spine of 12.64% and stomach of 0.95%. When the statistical error is performed for the computational human phantom, the statistical error of value is under 1%.

• Nuclear Engineering and Technology
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• 제38권3호
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• pp.239-250
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• 2006

Computational anthropomorphic phantoms are computer models of human anatomy used in the calculation of radiation dose distribution in the human body upon exposure to a radiation source. Depending on the manner to represent human anatomy, they are categorized into two classes: stylized and tomographic phantoms. Stylized phantoms, which have mainly been developed at the Oak Ridge National Laboratory (ORNL), describe human anatomy by using simple mathematical equations of analytical geometry. Several improved stylized phantoms such as male and female adults, pediatric series, and enhanced organ models have been developed following the first hermaphrodite adult stylized phantom, Medical Internal Radiation Dose (MIRD)-5 phantom. Although stylized phantoms have significantly contributed to dosimetry calculation, they provide only approximations of the true anatomical features of the human body and the resulting organ dose distribution. An alternative class of computational phantom, the tomographic phantom, is based upon three-dimensional imaging techniques such as magnetic resonance (MR) imaging and computed tomography (CT). The tomographic phantoms represent the human anatomy with a large number of voxels that are assigned tissue type and organ identity. To date, a total of around 30 tomographic phantoms including male and female adults, pediatric phantoms, and even a pregnant female, have been developed and utilized for realistic radiation dosimetry calculation. They are based on MRI/CT images or sectional color photos from patients, volunteers or cadavers. Several investigators have compared tomographic phantoms with stylized phantoms, and demonstrated the superiority of tomographic phantoms in terms of realistic anatomy and dosimetry calculation. This paper summarizes the history and current status of both stylized and tomographic phantoms, including Korean computational phantoms. Advantages, limitations, and future prospects are also discussed.