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Exposure and Toxicity Assessment of Ultrafine Particles from Nearby Traffic in Urban Air in Seoul, Korea

  • Yang, Ji-Yeon;Kim, Jin-Yong;Jang, Ji-Young;Lee, Gun-Woo;Kim, Soo-Hwan;Shin, Dong-Chun;Lim, Young-Wook
    • Environmental Analysis Health and Toxicology
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    • v.28
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    • pp.7.1-7.9
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    • 2013
  • Objectives We investigated the particle mass size distribution and chemical properties of air pollution particulate matter (PM) in the urban area and its capacity to induce cytotoxicity in human bronchial epithelial (BEAS-2B) cells. Methods To characterize the mass size distributions and chemical concentrations associated with urban PM, PM samples were collected by a 10-stage Micro-Orifice Uniform Deposit Impactor close to nearby traffic in an urban area from December 2007 to December 2009. PM samples for in vitro cytotoxicity testing were collected by a mini-volume air sampler with $PM_{10}$ and $PM_{2.5}$ inlets. Results The PM size distributions were bi-modal, peaking at 0.18 to 0.32 and 1.8 to $3.2{\mu}m$. The mass concentrations of the metals in fine particles (0.1 to $1.8{\mu}m$) accounted for 45.6 to 80.4% of the mass concentrations of metals in $PM_{10}$. The mass proportions of fine particles of the pollutants related to traffic emission, lead (80.4%), cadmium (69.0%), and chromium (63.8%) were higher than those of other metals. Iron was the dominant transition metal in the particles, accounting for 64.3% of the $PM_{10}$ mass in all the samples. We observed PM concentration-dependent cytotoxic effects on BEAS-2B cells. Conclusions We found that exposure to $PM_{2.5}$ and $PM_{10}$ from a nearby traffic area induced significant increases in protein expression of inflammatory cytokines (IL-6 and IL-8). The cell death rate and release of cytokines in response to the $PM_{2.5}$ treatment were higher than those with $PM_{10}$. The combined results support the hypothesis that ultrafine particles from vehicular sources can induce inflammatory responses related to environmental respiratory injury.

Hepatitis C Virus - Proteins, Diagnosis, Treatment and New Approaches for Vaccine Development

  • Keyvani, Hossein;Fazlalipour, Mehdi;Monavari, Seyed Hamid Reza;Mollaie, Hamid Reza
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.12
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    • pp.5917-5935
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    • 2012
  • Background: Hepatitis C virus (HCV) causes acute and chronic human hepatitis infection and as such is an important global health problem. The virus was discovered in the USA in 1989 and it is now known that three to four million people are infected every year, WHO estimating that 3 percent of the 7 billion people worldwide being chronically infected. Humans are the natural hosts of HCV and this virus can eventually lead to permanent liver damage and carcinoma. HCV is a member of the Flaviviridae family and Hepacivirus genus. The diameter of the virus is about 50-60 nm and the virion contains a single-stranded positive RNA approximately 10,000 nucleotides in length and consisting of one ORF which is encapsulated by an external lipid envelope and icosahedral capsid. HCV is a heterogeneous virus, classified into 6 genotypes and more than 50 subtypes. Because of the genome variability, nucleotide sequences of genotypes differ by approximately 31-34%, and by 20-23% among subtypes. Quasi-species of mixed virus populations provide a survival advantage for the virus to create multiple variant genomes and a high rate of generation of variants to allow rapid selection of mutants for new environmental conditions. Direct contact with infected blood and blood products, sexual relationships and availability of injectable drugs have had remarkable effects on HCV epidemiology. Hundreds of thousands of people die each year from hepatitis and liver cancer caused by HCV virus infection. Approximately 80% of patients with acute hepatitis C progress into a chronic disease state leading to serious hepatic disorders, 10-20% of which develop chronic liver cirrhosis and hepatocellular carcinoma. The incubation period of HCV is 6-8 weeks and the infection is often asymptomatic so it is very hard to detect at early stages, making early treatment very difficult. Therefore, hepatitis C is called a "silent disease". Neutralizing antibodies are produced against several HCV proteins during infection but the virus mutates to escape from antibodies. Some patients with chronic hepatitis C may have some symptoms such as fatigue, muscle aches, nausea and pain. Autoimmune and immunecomplex-mediated diseases have also been reported with chronic HCV infection.

Effect of Allopurinol on Ultrastructural Changes in Ischemia Reperfusion Injury to Skeletal Muscle of Rats After Graded Periods of Complete Ischemia (흰쥐에서 허혈시간에 따라 재관류후 나타나는 근조직의 미세구조 변화에 allopurinol이 미치는 영향)

  • Paik, Doo-Jin;Chun, Jae-Hong
    • Applied Microscopy
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    • v.25 no.3
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    • pp.51-62
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    • 1995
  • It has been well known that ischemia and reperfusion injury to skeletal muscle following an acute arterial occlusion causes significant morbidity and mortality. The skeletal muscle, which contains high energy phosphate compounds, has ischemic tolerance. During the ischemia, the ATP is catalyzed to hypoxanthine anaerobically and hypoxanthine dehydrogenase is converted to xanthine oxidase. During reperfusion, the hypoxanthine is catalyzed to xanthine by xanthine oxidase under $O_2$, presence and that results in production of cytotoxic oxygen free radicals. These cytotoxic free radicals, $O_2^-,\;H_{2}O_2,\;OH^-$, are toxic and make lesions in skeletal muscle during reperfusion. The authors perform the present study to investigate the effects of allopurinol, the inhibitor of xanthine oxidase, on reperfused ischemic skeletal muscles by observing the ultrastructural changes of the muscle fibers. A total of 48 healthy Sprague-Dawley rats weighing from 200 g to 250 g were used as experimental animals. Under urethane(3.0mg/kg., IP) anesthesia, lower abdominal incision was done and the left common iliac artery were ligated by using vascular clamp for 1, 2 and 6 hours. The left rectus femoris muscles were obtained at 6 hours after the removal of vascular clamp. In the allopurinol pretreated group, 50mg/kg of allopurinol was administered once a day for 2 days and before 2 hours of ischemia. The specimens were sliced into $1mm^3$ and prepared by routine methods for electron microscopic observations. All preparations were stained with uranyl acetate and lead citrate, and then observed with Hitachi -600 transmission electron microscope. The results were as follows: 1. In 1 hour ischemia/6 hours reperfused rectus femoris muscles of rats, decreased glycogen particles and electron density of mitochondrial matrix and dilated terminal cisternae are seen. In 2 hours ischemia/6 hours repersed rectus femoris muscles of rats, mitochondria with electron lucent matrix, irregularly dilated triad and spheromembranous bodies are observed. In 6 hours ischemia/6 hours reperfused rectus femoris muscles of rats, irregularly arranged myofibrils, and many spheromembranous bodies, fat droplets and lysosome are seen. 2. In 1 hour ischemia/6 hours reperfused rectus femoris muscles of rats pretreated with allopurinol, decreased glycogen particle and dilated cisternae of sarcoplasmic reticulum and triad are observed. In 2 hours ischemia/6 hours reperfused rectus femoris muscles of rats pretreated with allopurinol decreased electron density of mitochondrial matrix and spheromembranous bodies are seen. In 6 hours ischemia/6 hours reperfused rectus femoris muscles of rats pretreated with allopurinol, mitochondria with electron lucent matrix, spheromembranous bodies and dilated cisternae of sarcoplasmic reticulum and terminal cistern are observed. The results suggest that the allopurinol attenuates the damages of the skeletal muscles of rats during ischemia and reperfusion.

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Preparation of PZT Powders by Hydrothermal Synthesis : Effects of Starting Materials and the Agitation of Substrate on Powder Characteristics (수열합성법에 의한 PZT 분말제조 : 출발물질과 기질의 교반이 분말특성에 미치는 영향)

  • Jung, S.T.;Lee, K.J.;Seo, K.W.
    • Applied Chemistry for Engineering
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    • v.8 no.2
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    • pp.292-300
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    • 1997
  • In this study PZT powders were prepared with shapes of cubic by hydrothermal synthesis with various starting materials, and the sintering characteristics of the powders were investigated. The particle shapes were cubic regardless of starting materials, but the mean size of particles formed using $Pb(NO_3)_2$, $Ti(OC_4H_9)_4$ and $Zr(OC_4H_9)_4$ was relatively smaller than that of particles prepared from other starting materials. Agitation of the feedstock during hydrothermal reaction results in decreasing the required reaction temperature for the formation of nuclei, and in increasing the size of product particles. XRD results showed that the major phase of PZT crystal powders was a tetragonal phase at the Zr to Ti ratio of 40 to 60, or a rhombohedral phase at its ratio of 60 to 40. The density of a sintered body made from the hydrothermal powders in PbO surrounding varied with sintering temperatures and with periods of sintering time. The experimental results also showed that the optimum sintering condition was at $1150^{\circ}C$ for a 2hr sintering, and that the density of a sintered body was $7.6g/cm^3$.

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Nano-safety Management and Exposure Assessment of Nanomaterials Producing Facilities (나노물질 생산시설의 환경노출 평가와 안전관리)

  • Umh, Ha Nee;Roh, Jinkyu;Park, Junsu;Kwak, Byoung Kyu;Lee, Byung Cheon;Choi, Kyunghee;Yi, Jongheop;Kim, Younghun
    • Korean Chemical Engineering Research
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    • v.50 no.1
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    • pp.112-117
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    • 2012
  • With the development of nanotechnology, nano-consumer products have been popularized. For the past 10 years, potential risk of nanomaterials to human and environment have been raised carefully. Especially, workers, who directly handle nanomaterials in laboratories and manfacturers, will lead to direct exposure of nanomaterials. Therefore, direct exposure assessment and field monitoring of nanomaterials are required to assess and manage the nanomaterial exposure to human and environment. In this work, two nano-manufacturing companies, which had plasma and sol-gel processes, were selected to analyze the main exposure source and process with in-situ SMPS (scanning mobility particle sizer) and ex-situ TEM (transmission electron microscopy). The results showed that the colloidal nanoparticle in liquid phase was easily evaporated and monitored by SMPS. Most serious thing is that the workers does not know about the potential risk of nanomaterials, and thus they are not taking proper protection activities, such as PPE (personal protective equipment). Therefore, exposure assessment for nanomaterial handling facilities should be additionally carried out, and nano-safety management protocols are also provided.

Preliminary Study for Imaging of Therapy Region from Boron Neutron Capture Therapy (붕소 중성자 포획 치료에서 치료 영역 영상화를 위한 예비 연구)

  • Jung, Joo-Young;Yoon, Do-Kun;Han, Seong-Min;Jang, HongSeok;Suh, Tae Suk
    • Progress in Medical Physics
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    • v.25 no.3
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    • pp.151-156
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    • 2014
  • The purpose of this study was to confirm the feasibility of imaging of therapy region from the boron neutron capture therapy (BNCT) using the measurement of the prompt gamma ray depending on the neutron flux. Through the Monte Carlo simulation, we performed the verification of physical phenomena from the BNCT; (1) the effects of neutron according to the existence of boron uptake region (BUR), (2) the internal and external measurement of prompt gamma ray dose, (3) the energy spectrum by the prompt gamma ray. All simulation results were deducted using the Monte Carlo n-particle extended (MCNPX, Ver.2.6.0, Los Alamos National Laboratory, Los Alamos, NM, USA) simulation tool. The virtual water phantom, thermal neutron source, and BURs were simulated using the MCNPX. The energy of the thermal neutron source was defined as below 1 eV with 2,000,000 n/sec flux. The prompt gamma ray was measured with the direction of beam path in the water phantom. The detector material was defined as the lutetium-yttrium oxyorthosilicate (Lu0,6Y1,4Si0,5:Ce; LYSO) scintillator with lead shielding for the collimation. The BUR's height was 5 cm with the 28 frames (bin: 0.18 cm) for the dose calculation. The neutron flux was decreased dramatically at the shallow region of BUR. In addition, the dose of prompt gamma ray was confirmed at the 9 cm depth from water surface, which is the start point of the BUR. In the energy spectrum, the prompt gamma ray peak of the 478 keV was appeared clearly with full width at half maximum (FWHM) of the 41 keV (energy resolution: 8.5%). In conclusion, the therapy region can be monitored by the gamma camera and single photon emission computed tomography (SPECT) using the measurement of the prompt gamma ray during the BNCT.

The Relation between Obesity and Glomerular Filtration Rate in Children and Adolescents (소아 및 청소년에서 비만과 사구체여과율과의 관계)

  • Jung, Youngsu;Kim, Dongwoon;Lim, Inseok
    • Clinical and Experimental Pediatrics
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    • v.48 no.11
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    • pp.1219-1224
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    • 2005
  • Purpose : The prevalence of obesity in children and adolescents has been rising rapidly in Korea because of changes of diet and lifestyle. As with adults, obesity in children and adolescents can cause diabetes mellitus, hyperlipidemia, cardiovascular diseases and renal diseases. The aim of the present study is to examine the relation of obesity, glomerular filtration rate(GFR) and serum cystatin C concentration in children and adolescents. Methods : Data of 115 children and adolescents aged between 6 years and 20 years without clinical evidence of renal diseases were included in the study. From May 2004 to December 2004, blood samples were collected from children and adolescents who were seen at the Department of Pediatrics at Chungang University Yongsan Hospital. Obesity degrees and body mass indices(BMI) were measured, and GFRs were estimated from Schwartz's formula. Serum cystatin C was measured by particle enhanced nephelometric immunoassay using Behring Nephelometer II. Results : GFRs were significantly different between the obese group(BMI >95 percentile, $145.79{\pm}23.10mL/min$) and the non-obese group(BMI <95 percentile, $134.61{\pm}26.19mL/min$) divided by BMI (P=0.031). GFRs were not significantly different between the obese group(obesity degree >120 percent, $144.29{\pm}23.08mL/min$) and the non-obese group(obesity degree <120 percent, $134.54{\pm}26.57mL/min$) divided by obesity degree(P=0.051), but were significantly different between severe obese group (obesity degree >150 percent, $155.55{\pm}20.40mL/min$) and the non-obese group(P=0.004). GFRs were correlated positively with BMI($r^2=0.037$, P=0.039), but were not correlated significantly with obesity degree($r^2=0.030$, P=0.066). Serum cystatin C concentrations were not significantly different between the obese group and the non-obese group, divided by BMI as well as by obesity degree(P>0.05). Conclusion : Obesity may lead to an alteration of renal hemodynamics such as hyperfiltration, appropriate control and management for obesity is necessary.

Stellite bearings for liquid Zn-/Al-Systems with advanced chemical and physical properties by Mechanical Alloying and Standard-PM-Route

  • Zoz, H.;Benz, H.U.;Huettebraeucker, K.;Furken, L.;Ren, H.;Reichardt, R.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2000.04a
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    • pp.9-10
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    • 2000
  • An important business-field of world-wide steel-industry is the coating of thin metal-sheets with zinc, zinc-aluminum and aluminum based materials. These products mostly go into automotive industry. in particular for the car-body. into building and construction industry as well as household appliances. Due to mass-production, the processing is done in large continuously operating plants where the mostly cold-rolled metal-strip as the substrate is handled in coils up to 40 tons unwind before and rolled up again after passing the processing plant which includes cleaning, annealing, hot-dip galvanizing / aluminizing and chemical treatment. In the liquid Zn, Zn-AI, AI-Zn and AI-Si bathes a combined action of corrosion and wear under high temperature and high stress onto the transfer components (rolls) accounts for major economic losses. Most critical here are the bearing systems of these rolls operating in the liquid system. Rolls in liquid system can not be avoided as they are needed to transfer the steel-strip into and out of the crucible. Since several years, ceramic roller bearings are tested here [1.2], however, in particular due to uncontrollable Slag-impurities within the hot bath [3], slide bearings are still expected to be of a higher potential [4]. The today's state of the art is the application of slide bearings based on Stellite\ulcorneragainst Stellite which is in general a 50-60 wt% Co-matrix with incorporated Cr- and W-carbides and other composites. Indeed Stellite is used as the bearing-material as of it's chemical properties (does not go into solution), the physical properties in particular with poor lubricating properties are not satisfying at all. To increase the Sliding behavior in the bearing system, about 0.15-0.2 wt% of lead has been added into the hot-bath in the past. Due to environmental regulations. this had to be reduced dramatically_ This together with the heavily increasing production rates expressed by increased velocity of the substrate-steel-band up to 200 m/min and increased tractate power up to 10 tons in modern plants. leads to life times of the bearings of a few up to several days only. To improve this situation. the Mechanical Alloying (MA) TeChnique [5.6.7.8] is used to prOduce advanced Stellite-based bearing materials. A lubricating phase is introduced into Stellite-powder-material by MA, the composite-powder-particles are coated by High Energy Milling (HEM) in order to produce bearing-bushes of approximately 12 kg by Sintering, Liquid Phase Sintering (LPS) and Hot Isostatic Pressing (HIP). The chemical and physical behavior of samples as well as the bearing systems in the hot galvanizing / aluminizing plant are discussed. DependenCies like lubricant material and composite, LPS-binder and composite, particle shape and PM-route with respect to achievable density. (temperature--) shock-reSistibility and corrosive-wear behavior will be described. The materials are characterized by particle size analysis (laser diffraction), scanning electron microscopy and X-ray diffraction. corrosive-wear behavior is determined using a special cylinder-in-bush apparatus (CIBA) as well as field-test in real production condition. Part I of this work describes the initial testing phase where different sample materials are produced, characterized, consolidated and tested in the CIBA under a common AI-Zn-system. The results are discussed and the material-system for the large components to be produced for the field test in real production condition is decided. Outlook: Part II of this work will describe the field test in a hot-dip-galvanizing/aluminizing plant of the mechanically alloyed bearing bushes under aluminum-rich liquid metal. Alter testing, the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed. Part III of this project will describe a second initial testing phase where the won results of part 1+11 will be transferred to the AI-Si system. Part IV of this project will describe the field test in a hot-dip-aluminizing plant of the mechanically alloyed bearing bushes under aluminum liquid metal. After testing. the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed.

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Object Tracking Based on Exactly Reweighted Online Total-Error-Rate Minimization (정확히 재가중되는 온라인 전체 에러율 최소화 기반의 객체 추적)

  • JANG, Se-In;PARK, Choong-Shik
    • Journal of Intelligence and Information Systems
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    • v.25 no.4
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    • pp.53-65
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    • 2019
  • Object tracking is one of important steps to achieve video-based surveillance systems. Object tracking is considered as an essential task similar to object detection and recognition. In order to perform object tracking, various machine learning methods (e.g., least-squares, perceptron and support vector machine) can be applied for different designs of tracking systems. In general, generative methods (e.g., principal component analysis) were utilized due to its simplicity and effectiveness. However, the generative methods were only focused on modeling the target object. Due to this limitation, discriminative methods (e.g., binary classification) were adopted to distinguish the target object and the background. Among the machine learning methods for binary classification, total error rate minimization can be used as one of successful machine learning methods for binary classification. The total error rate minimization can achieve a global minimum due to a quadratic approximation to a step function while other methods (e.g., support vector machine) seek local minima using nonlinear functions (e.g., hinge loss function). Due to this quadratic approximation, the total error rate minimization could obtain appropriate properties in solving optimization problems for binary classification. However, this total error rate minimization was based on a batch mode setting. The batch mode setting can be limited to several applications under offline learning. Due to limited computing resources, offline learning could not handle large scale data sets. Compared to offline learning, online learning can update its solution without storing all training samples in learning process. Due to increment of large scale data sets, online learning becomes one of essential properties for various applications. Since object tracking needs to handle data samples in real time, online learning based total error rate minimization methods are necessary to efficiently address object tracking problems. Due to the need of the online learning, an online learning based total error rate minimization method was developed. However, an approximately reweighted technique was developed. Although the approximation technique is utilized, this online version of the total error rate minimization could achieve good performances in biometric applications. However, this method is assumed that the total error rate minimization can be asymptotically achieved when only the number of training samples is infinite. Although there is the assumption to achieve the total error rate minimization, the approximation issue can continuously accumulate learning errors according to increment of training samples. Due to this reason, the approximated online learning solution can then lead a wrong solution. The wrong solution can make significant errors when it is applied to surveillance systems. In this paper, we propose an exactly reweighted technique to recursively update the solution of the total error rate minimization in online learning manner. Compared to the approximately reweighted online total error rate minimization, an exactly reweighted online total error rate minimization is achieved. The proposed exact online learning method based on the total error rate minimization is then applied to object tracking problems. In our object tracking system, particle filtering is adopted. In particle filtering, our observation model is consisted of both generative and discriminative methods to leverage the advantages between generative and discriminative properties. In our experiments, our proposed object tracking system achieves promising performances on 8 public video sequences over competing object tracking systems. The paired t-test is also reported to evaluate its quality of the results. Our proposed online learning method can be extended under the deep learning architecture which can cover the shallow and deep networks. Moreover, online learning methods, that need the exact reweighting process, can use our proposed reweighting technique. In addition to object tracking, the proposed online learning method can be easily applied to object detection and recognition. Therefore, our proposed methods can contribute to online learning community and object tracking, detection and recognition communities.

Dosimetry of the Low Fluence Fast Neutron Beams for Boron Neutron Capture Therapy (붕소-중성자 포획치료를 위한 미세 속중성자 선량 특성 연구)

  • Lee, Dong-Han;Ji, Young-Hoon;Lee, Dong-Hoon;Park, Hyun-Joo;Lee, Suk;Lee, Kyung-Hoo;Suh, So-Heigh;Kim, Mi-Sook;Cho, Chul-Koo;Yoo, Seong-Yul;Yu, Hyung-Jun;Gwak, Ho-Shin;Rhee, Chang-Hun
    • Radiation Oncology Journal
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    • v.19 no.1
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    • pp.66-73
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    • 2001
  • Purpose : For the research of Boron Neutron Capture Therapy (BNCT), fast neutrons generated from the MC-50 cyclotron with maximum energy of 34.4 MeV in Korea Cancer Center Hospital were moderated by 70 cm paraffin and then the dose characteristics were investigated. Using these results, we hope to establish the protocol about dose measurement of epi-thermal neutron, to make a basis of dose characteristic of epi-thermal neutron emitted from nuclear reactor, and to find feasibility about accelerator-based BNCT. Method and Materials : For measuring the absorbed dose and dose distribution of fast neutron beams, we used Unidos 10005 (PTW, Germany) electrometer and IC-17 (Far West, USA), IC-18, ElC-1 ion chambers manufactured by A-150 plastic and used IC-l7M ion chamber manufactured by magnesium for gamma dose. There chambers were flushed with tissue equivalent gas and argon gas and then the flow rate was S co per minute. Using Monte Carlo N-Particle (MCNP) code, transport program in mixed field with neutron, photon, electron, two dimensional dose and energy fluence distribution was calculated and there results were compared with measured results. Results : The absorbed dose of fast neutron beams was $6.47\times10^{-3}$ cGy per 1 MU at the 4 cm depth of the water phantom, which is assumed to be effective depth for BNCT. The magnitude of gamma contamination intermingled with fast neutron beams was $65.2{\pm}0.9\%$ at the same depth. In the dose distribution according to the depth of water, the neutron dose decreased linearly and the gamma dose decreased exponentially as the depth was deepened. The factor expressed energy level, $D_{20}/D_{10}$, of the total dose was 0.718. Conclusion : Through the direct measurement using the two ion chambers, which is made different wall materials, and computer calculation of isodose distribution using MCNP simulation method, we have found the dose characteristics of low fluence fast neutron beams. If the power supply and the target material, which generate high voltage and current, will be developed and gamma contamination was reduced by lead or bismuth, we think, it may be possible to accelerator-based BNCT.

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