• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.5
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• pp.802-808
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• 1994

The purpose of this paper is to describe an application of plasma polymerized thin film as an electron beam resist. Plasma polymerized thin film was prepared using an interelectrode capacitively coupled gas-flow-type reactor, and chosen methylmethacrylate(MMA)and methylmethacrylate-tetrameth-yltin(MMA-TMT) as a monomer. This thin films were also delineated by the electron-beam apparatus with an acceleration voltage of 30kV and an expose dose ranging from 20 to 900$\mu$C/cmS02T. The delineated pattern in the resist was developed with the same reactor which is used for polymerization using an argon as etching gas. The growth rate and etching rate of the thin film is increased with increasing of discharge power. Thin films by plasma polymerization show polymerization rate of 30~45($\pm$3) A/min, and etching rate of 440($\pm$30) A/min during Ar plasma etching at discharge power of 100W. In apparently lower than that of conventional PMMA, but the plasma-etching rate of PP(MMA-TMT) was higher than that of PPMMA.

• The Journal of Korean Society for Radiation Therapy
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• v.23 no.2
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• pp.91-96
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• 2011

Purpose: The aim of study is to expose a more uniform dose depending on the relationship between a body mass index in patients who underwent radiation therapy and an acquired dosimetric information by using a thermoluminescent dosimeter. Materials and Methods: Since 2006 to August 2011 we investigated 28 people who underwent radiation therapy were enrolled in AMC. Each patient was measured on the head, neck, chest, abdomen, pelvis, thigh, knee joint, and ankle joint using the thermoluminescent dosimeter. The measurement value of each points compared with the prescribed center point, abdominal point, and dose measurements of points on which to base the abdomen and the patient's body mass index (BMI) were compared with reference point, abdomen dose. Results: 28 patients on prescribed dose in the abdomen by which the center point, an average dose was $100.6{\pm}5.5%$, and the other seven measuring points with the average maximum difference among the head, neck, chest, pelvic, thigh, knee, and ankle were $92.8{\pm}4.2%$, $97.6{\pm}6.2%$, $96.4{\pm}5.5%$, $102.6{\pm}5.3%$, $103.4{\pm}7.9%$, $95.8{\pm}5.9%$, $96.1{\pm}5.5%$. The relationship of abdominal point dose and the patient's body mass index (BMI) was analyzed a scatter plot, and the result of linear relationship analysis by regression method, the regression of the dose (y) was -1.009 BMI (x) plus 123.3 and coefficient of determination ($R^2$) was represented 0.697. Conclusion: The total body irradiation treatment process was evaluated the dose deviation and then the prescribed dose by which the average abdominal dose was satisfied with $100.6{\pm}5.5%$. Results of the relationship analysis between BMI and dose, if we apply the correction value for each patients, it can be achieved more uniform dose delivery.

• Journal of radiological science and technology
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• v.38 no.2
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• pp.121-126
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• 2015

To image diagnosis in neurovascular diseases using Multi-Detector Computed Tomography(MDCT), injected the same contrast material when inspecting Brain Computed Tomography Angiography(BCTA) to examine radiation dose and Image quality on changing Cerebral Artery CT number by tube voltage. Executed an examination with same condition[Beam Collimation $128{\times}0.6mm$, Pitch 0.6, Rotation Time 0.5s, Slice Thickness 5.0mm, Increment 5.0mm, Delay Time 3.0sec, Care Dose 4D(Demension ; D)] except for tube voltage on 50 call patients for BCTA and divided them into two groups (25 people for a group, group A: 80, group B: 120kVp). From all the acquired images, set a ROI(Region of Interest) on four spots such as left cerebral artery, right cerebral artery, posterior cerebral artery and cerebral parenchyma to compare quantitative evaluation, qualitative evaluation and effective dose after measuring CT number value from Picture Archiving Communications System(PACS). Evaluating images with CT number acquired from BCTA examination, images with 80 kVp was 18% higher in Signal to Noise Ratio and 19% in Contrast to Noise Ratio than those with 120 kVp. It was seen that expose dose was decreased by over 50% with tube voltage 80 kVp than with 120 kVp. Group A (25 patients) was examination with tube voltage 80kVp while group B with 120 kVp to examine radiation dose and Image quality. It is considered effective to inspect with lower tube voltage than with conventional high kVp, which can reduce radiation dose without any affect on diagnosis.

• Progress in Medical Physics
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• v.20 no.2
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• pp.112-118
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• 2009

The source position and source dwelling time in a given source arrangement in the applicators is very high effect to determine the expose time which in general is derived from the brachytherapy planning system. In high dose rate (HDR) intracavitary radiation therapy (ICRT), the treatment is often performed in based out-patient during the whole fractionation irradiations. However, the patient should be waited on coutch for ICR treatment in first start fraction as unconvinent and immobilized state until perform the dose plannings. In our experiments, the HDR source contributed dose for$55.89{\pm}4.20%$ for straight tandem source, $38.14{\pm}4.46%$ for the right ovoid soucre on the fornix and$5.97{\pm}0.50%$ for left ovoid source. It also showed the $60.33{\pm}6.53%$ for the tandem, $33.10{\pm}6.74%$ for right ovoid and $6.58{\pm}0.30%$ for the left ovoid source in 10 degrees of applicator. The authors designed the source template dose planning software for ICRT of uterine cervix results average $-0.55{\pm}2.15%$ discrepancy of the full charged brachytherapy dose planning. Developed Source temperate ICRT plaanning software guide a minimized the complains and operating times within a ${\pm}3%$ of dose discrepancies.

• Journal of radiological science and technology
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• v.34 no.4
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• pp.305-314
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• 2011

The purpose of this study was to compare the findings on the chest low-dose CT (LDCT) images between the negative and positive groups for pneumoconiosis in the group exposed to inorganic dust. From May 30, 2007 to August 31, 2008, total 328 subjects were examined by a LDCT. LDCT images were read by a chest radiologist who has much experience for reading of pneumoconiosis. All subjects were classified into two groups based on digital images after consensus reading of two radiologists according to the ILO 2000 guidelines; negative group (87, 26.5%) without pneumoconiosis and positive group (241, 73.5%). Statistical analysis was performed using a SPSS 14.0. There were significant differences in age (60.9 vs. 65.0, p<0.001), and in dust expose duration (17.0 vs. 19.2, p=0.024) between two groups, but no significant difference in smoking (p=0.784). Of the 328 subjects, 13 diagnosis were extracted from 245 subjects (74.7%). Coronary artery calcification (CAC) was significantly higher in positive group than that in negative group (36.9% vs. 25.3%, p=0.049). Honeycombing showed higher frequency in positive group than in negative group (6.2% vs. 1.2%, p=0.079). Pneumoconiosis findings caused by inorganic dusts exposure showed the significant relation with CAC on LDCT images. Future studies need to prove that pneumoconiosis finding is independent risk factor for CAC using a coronary artery angiography.

• Journal of radiological science and technology
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• v.44 no.3
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• pp.253-260
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• 2021

The purpose of this study is to measure of growth and chlorophyl in barley exposed by X-ray. Barley seed was soaked 24h duration in water, then was classified into two group; pre-seed germination group (Pre-G) or post-seed germination group (Post-G). Also, divided as control subgroup and experimental subgroup(10Gy, 20Gy, 30Gy) in each group. Experimental subgroups were exposed by X-ray using linear accelerator (Clinac IS, VERIAN, USA). Expose condition was 6 MV X-ray, SSD 100 cm, 18×10 cm, 600 MU/min. Length was measured every day for 10 days and 10th day for weight. Chlorophyl was analyzed using spectrophotometer(uv-1800, shimadzu, japan) in l0th day. Data analysis was performed using SPSS ver 22.0(Chicago, IL, USA), ANOVA test (Dunnett_T3) between control subgroup and experimental subgroup in group and Independent T-test between Pre-G and Post-G in subgroup. In Pre-G, length of barley was significantly difference between control and 30Gy in 4th day (4.3 vs. 1.5, p= 0.011). Length of 30Gy was statistical difference with control(10th day; 14.4 vs. 6.3, p < 0.01), and was not in 10Gy or 20Gy in all day. In experimental subgroup, length was shorter as increasing radiation dose. In Post-G, length of barley was not difference statistically between control and experimental subgroup in first day, but more difference between two subgroup with increasing duration after exposing. Length of experimental subgroup was shorter significantly compared with control in 10th day, and no significant difference between experimental subgroup. Density of chlorophyl was increasing with increasing radiation dose in Pre-G and Post-G. Chlorophyl density of control was lower than 30Gy; 0.26ppm in Pre-G, 0.29ppm in Post-G). Growth and chlorophyl of barley was effected by X-ray. It is expected to be used as basic data for future radiobiological research.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.77-82
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• 2010

Purpose: As PET/CT come into wide use, it caused increasing of expose in clinical use. Therefore, Korea Food and Drug Administration issued Patient DRL (Diagnostic Reference Level) in CT scan. In this study, to build the basis of patient dose reduction, we analyzed effective dose in transmission scan with CT scan. Materials and Methods: From February, 2010 to March 180 patients (age: $55{\pm}16$, weight: $61.0{\pm}10.4$ kg) who examined $^{18}F$-FDG PET/CT in Asan Medical Center. Biograph Truepoint 40 (SIEMENS, GERMANY), Biograph Sensation 16 (SIEMENS, GERMANY) and Discovery STe8 (GE healthcare, USA) were used in this study. Per each male and female average of 30 patients doses were analyzed by one. Automatic exposure control system for controlling the dose can affect the largest by a patient's body weight less than 50 kg, 50-60 kg less, 60 kg more than the average of the three groups were divided doses. We compared that measured value of CT-expo v1.7 and ImPACT v1.0. The relationship between body weight and the effective dose were analyzed. Results: When using CT-Expo V1.7, effective dose with BIO40, BIO16 and DSTe8 respectably were $6.46{\pm}1.18$ mSv, $9.36{\pm}1.96 $mSv and $9.36{\pm}1.96$ mSv for 30 male patients respectably $6.29{\pm}0.97$ mSv, $10.02{\pm}2.42$ mSv and $9.05{\pm}2.27$ mSv for 30 female patients respectably. When using ImPACT v1.0, effective dose with BIO40, BIO16 and DSTe8 respectably were $6.54{\pm}1.21$ mSv, $8.36{\pm}1.69$ mSv and $9.74{\pm}2.55$Sv for 30 male patients respectably $5.87{\pm}1.09$ mSv, $8.43{\pm}1.89$ mSv and $9.19{\pm}2.29$ mSv for female patients respectably. When divided three groups which were under 50 kg, 50~60 kg and over 60 kg respectably were 6.27 mSv, 7.67 mSv and 9.33 mSv respectably using CT-Expo V1.7, 5.62 mSv, 7.22 mSv and 8.91 mSv respectably using ImPACT v1.0. Weight and the effective dose coefficient analysis showed a very strong positive correlation(r=743, r=0.693). Conclusion: Using such a dose evaluation programs, easier to predict and evaluate the effective dose possible without performing phantom study and such dose evaluation programs could be used to collect basic data for CT dose management.

• Journal of radiological science and technology
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• v.35 no.2
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• pp.141-149
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• 2012

The aims of this study are to assess external radiation exposed doses of body and hands of nuclear medicine workers who handle radiation sources, and to measure radiation exposed doses of the hands induced by a whole body bone scan with high frequency and handling a radioactive sources like $^{99m}Tc$-HDP and $^{18}F$-FDG in the PET/CT examination. Skillful workers, who directly dispense and inject from radiation sources, were asked to wear a TLD on the chest and ring finger. Then, radiation exposed dose and duration exposed from daily radiation sources for each section were measured by using a pocket dosimeter for the accumulated external doses and the absorbed dose to the hands. In the survey of four medical institutions in Incheon Metropolitan City, only one of four institutions has a radiation dosimeter for local area like hands. Most of institutions uses radiation shielding devices for the purpose of protecting the body trunk, not local area. Even some institutions were revealed not to use such a shielding device. The exposed doses on the hands of nuclear medicine workers who directly handles radioactive sources were approximately twice as much as those on the body. The radiation exposure level for each section of the whole body bone scan with high frequency and that of the PET/CT examination showed that radiation doses were revealed in decreasing order of synthesis of radioactive medicine and installation to a dispensing container, dispensing, administering and transferring. Furthermore, there were statistically significant differences of radiation exposure doses of the hands before and after wearing a syringe shielder in administration of a radioactive sources. In this study, although it did not reach the permissible effective dose for nuclear medicine, the occupational workers were exposed by relatively higher dose level than the non-occupational workers. Therefore, the workers, who closely exposed to radioactive sources should be in compliance with safety management regulations, and take actions to maximally reduce locally exposed dose to hands monitoring with ring TLD.

• Journal of Environmental Science International
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• v.16 no.3
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• pp.323-331
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• 2007

Polycyclic aromatic hydrocarbons (PAHs) are well known for strong carcinogen. However, the human exposure analysis of PAHs is quite difficult and unreliable because of hard for estimation of actual expose dose. Then urinary 1-hydroxypyrene (1-OHP) has been a biological marker of exposure to PAHs. The purpose of this study was to investigate total amount from exposure to PAHs soused by indoor occupational exposure, and residence at Seoul metropolitan area and Kyeonggi province in Korea. Thirty-five housewives were included in this study from April 2003 through February 2004. Dietary habit and general characteristics such as age, type of building, existence of passive smoking, period of residence, fuel type for heating and ventilation type were obtained by self administered questionnaire. Urine samples were collected at morning and freeze quickly. Urinary creatinine was measured for converting into 24 hr urine. Concentration of the indoor PAHs was examined by NIOSH method number 5506. Urinary 1-OHP and PAHs were analysed by HPLC. Correlation coefficient between urinary 1-OHP levels and pyrene concentration of indoor air was 0.66 and statistically significant(P<0.01). The difference of urinary 1-OHP level due to dietary habits were not significant. Urinary 1-OHP level of Spring, Summer, Autumn, and Winter were $0.21{\pm}0.12,\;0.10{\pm}0.17,\;0.16{\pm}0.12,\;0.17{\pm}0.14{\mu}g/g$ cr, respectively. The arithmetic means of urinary 1-OHP for four season tee $0.16{\pm}0.14 {\mu}g/g$ cr. There was a trend that urinary 1-OHP level of residents who dwelling in apartment were higher compared with detached home, Comparison of 1-OHP level between heating by kerosene and LPG, Much higher gas heating type than kerosene type (P<0.05). This result implies that the urinary 1-OHP can be applied as the PAHs exposure indices.

• The Korean Journal of Pharmacology
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• v.32 no.3
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• pp.433-444
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• 1996

We describe a novel approach to evaluate quantitatively the amounts of denatured proteins in cells upon heat exposure. A thiol compound, diamide [azodicarboxylic acid bis (dimethylamide)] causes protein cross-linking with exposed sulfyhydryl residues of denatured proteins. Since denatured proteins expose normally well-hidden sulfhydryl groups, these will be preferentially cross-linked by diamide. Thus diamide acts to 'trap' denatured proteins. We observed that protein aggregates (high molecular weight protein aggregates, HMA) appeared on SDS-polyacrylamide gels run under non-reducing conditions and that the amount of HMA can be quantified by scanning the gels using a gas flow counter. Heating cells followed by a fixed dose of diamide exposure resulted in HMA increases in a heat-dose dependent manner, demonstrating that the quantitation of HMA could serve as a measure of heat-denatured proteins. We compared thermotolerant and nontolerant cells and found decreased HMA in tolerant cells upon heat treatment. As an attempt to examine the kinetics of protein renaturation (or 'repair'), we measured the amounts of aggregates formed by the addition of diamide at various times after heat shock. Such experiments demonstrate an equally rapid disappearance of HMA in previously unheated and in thermotolerant cells. Levels of HMA in tolerant cells increased significantly after electroporation of HSP70 specific mAbs, suggesting an involvement of HSP70 in reducing HMA levels in thermotolerant cells upon heat exposure. Immunoprecipitation studies using anti-HSP70 antibody indicated an association of HSP70 with heat-denatured proteins. Our results suggest that heat induces protein denaturation, and that elevated level of HSP70 present in thermotolerant cells protects them by reducing the level of protein denaturation rather than by facilitating the 'repair' (or degradation) process.