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Evaluation for Optimization of CT Dose Reduction Methods in PET/CT (PET/CT 검사 시 CT 피폭선량 감소 방법들의 최적화 평가)

  • Do, Yong Ho;Lee, Hong Jae;Kim, Jin Eui
    • The Korean Journal of Nuclear Medicine Technology
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    • v.19 no.2
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    • pp.55-62
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    • 2015
  • Purpose Various methods for reducing radiation exposure have been continuously being developed. The aim of this study is to evaluate effectiveness of dose reduction, image quality and PET SUV changes by applying combination of automatic exposure dose(AEC), automated dose-optimized selection of X-ray tube voltage(CAREkV) and sinogram affirmed iterative reconstruction(SAFIRE) which can be controled by user. Materials and Methods Torso, AAPM CT performance and IEC body phantom images were acquired using biograph mCT64, (Siemens, Germany) PET/CT scanner. Standard CT condition was 120 kV, 40 mAs. Radiation exposure and noise were evaluated by applying AEC, CAREkV(120 kV, 40 mAs) and SAFIRE(120 kV, 25 mAs) with torso phantom compare to standard CT condition. And torso, AAPM and IEC phantom images were acquired with combination of 3 methods in condition of 120 kV, 25 mAs to evaluate radiation exposure, noise, spatial resolution and SUV changes. Results When applying AEC, CTDIvol and DLP were decreased by 50.52% and 50.62% compare to images which is not applying AEC. mAs was increased by 61.5% to compensate image quality according to decreasing 20 kV when applying CAREkV. However, CTDIvol and DLP were decreased by 6.2% and 5.5%. When reference mAs was the lower and strength was the higher, reduction of radiation exposure rate was the bigger. Mean SD and DLP were decreased by 2.2% and 38% when applying SAFIRE even though mAs was decreased by 37.5%(from 40 mAs to 25 mAs). Combination of 3 methods test, SD decreased by 5.17% and there was no significant differences in spatial resolution. And mean SD and DLP were decreased by 6.7% and 36.9% compare to 120 kV, 40 mAs with AEC. For SUV test, there was no statistical differences(P>0.05). Conclusion Combination of 3 methods shows dose reduction effect without degrading image quality and SUV changes. To reduce radiation exposure in PET/CT study, continuous effort is needed by optimizing various dose reduction methods.

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Image Quality Assessment Model of Natural Scene Based on Normal Distribution Analysis (일반 장면의 정규분포 분석을 기반으로 한 화질 측정 모형)

  • Park, Hyung-Ju;Har, Dong-Hwan
    • Science of Emotion and Sensibility
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    • v.16 no.3
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    • pp.373-386
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    • 2013
  • In this research, we specify the image consumers' preferred image quality ranges based on objective image quality evaluation factors and follow a method which measures preference of the natural image scenes. In other words, according to No-Reference, we select dynamic range, color, and contrast as factors of image quality measurements. For collecting sample images, we choose the preferred 200 landscapes which have over 30 recommendations by image consumers on the internet photo gallery. According to the scores of three objective factors of image quality measurements, the final expected score which means the image quality preference is measured and its total score is 100 points. In the main test, the actual image sample shows dynamic range 10 stop, LAB mean value L:54.7, A:2.96, B:-15.84, and RSC contrast 376.9. Total 200 image samples' normal distribution z value represents in dynamic range 0.21, LAB mean value L:0.15, A:0.38, B:0.13, and RSC contrast 0.08. In the standard normal distribution table, we can convert the z value as a percentage; dynamic range is 8.32%, LAB mean value is L:5.96%, A:14.8%, B:5.17%, and RSC contrast is 3.19%. And then, we convert the percentage values into the scores of 100; dynamic range is 91.68, LAB mean value is 91.36, and RSC contrast is 96.81. Therefore, we can conclude that the sample image's total mean score is 94.99 based on three objective image quality factors. Throughout our proposed image quality assessment model, we can measure the preference value of natural scenes. Also, we can specify the preferred image quality representation ranges and measure the expected image quality preference.

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The Effects of Sex Education on the Primary Schooler's Knowledge and Attitude about Sex (성교육이 국민학생의 성지식과 성태도에 미치는 효과)

  • Kim, Jin-Son
    • Women's Health Nursing
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    • v.1 no.2
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    • pp.200-221
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    • 1995
  • The confusion of the sense of value on sex is increasing because of the rapid change in social-cultural environment. Also due to a rise in the standard of living, the age of adolescence is getting lower, and so the second sexual marks appear to primary schoolers. At this time in the aspect of the education for the whole man, it's very important for primary schoolers to acquire right knowledge and desirable attitude on sex so that can overcome psychological instability caused by physical growth, be responsible for their behaviors and lead happy lives. This study was made to find out the effects of sex education for the primary schoolers' knowledge and attitude about sex. The study was designed as simulated control group pretest-posttest design, which only pretest was practiced to control group and after sex education only posttest was practiced to experimental group. The data was collected for 18 days from March 13, 1995 to March 31, 1995. The subjects of this study were 130 six-graders in a private primary school in seoul. The control group and experimental group were composed of 65 pupils, each. Sex education consisted of lecture and discussion and the materials were this researcher's own made, 'How do I grow? and related OHP film and video. This education was practiced 40 minutes at a time, at intervals of 2-4 days' six times during 3weeks. For sex knowledge tools, 20 item questionaries on the base of related reference books and contents of this study were used. For sex attitude tools, this researcher's own made 13 item questionaries were used which were revised and complemented and laying stress on the reference books. The data was analyzed through pc-SAS program. The homogeneity test in terms of the general characteristics of experimental and control group was analyzed through $x^2$-test and t-test. And the difference in the primary schoolers' score on knowledge and attitude about sex before and after the sex education was analyzed through t-test and ANCOVA. The results of this study are as follows : 1. The result of the homogeneity test in terms of the general characteristics of the experimental and control group showed that there were significant differences in economic standard($x^2$=2.92, P=0.052) and brotherly ties($x^2$=3.78, P=0.052). 2. Hypothesis 'After sex education, the score of primary schoolers' sex knowledge will be higher than before. 'showed statistically significant difference.(t=11.99, P=.0001) Sex education was practiced under control over subjective view of economic standard and brotherly ties which showed significant difference at the homogeneity test in terms of the general characteristics between the two groups. After this education, the results of comparing the score of primary schoolers' sex knowledge also showed significant difference between the two groups. So hypothesis I was supported since primary schoolers to have education showed noticeable results in the sex knowledge score. (F=16.52, P=.0001) 3. Hypothesis 'After sex education, primary schooler's sex attitude score will be higher than before' showed statistically significant(t=5.08, P=.0001) Sex education was practiced, too, under control over subjective view of economic standard and brotherly ties which showed significant difference at the homogeneity test in terms of the general characteristics between the two groups. Bat this time the results of comparing the primary schoolers' sex attitude showed no significant difference between the two groups. So hypothesis II was rejected since for primary schoolers to have sex education showed no noticeable results in sex attitude score. (F=3.52, P=.0628) These results of the study show that sex education gives affirmative change to the primary schooler's sex knowledge, bat short periods' sex education doesn't give any change to the sex attitude. For the establishment of the pupils' desirable sex attitude, systematic and concrete sex education fit for the pupils' developing stage should be practiced over a long period of time.

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Report on the Stability of Freeze-dried Standard Solution (동결건조표준액의 안정성에 관한 보고)

  • Park, Jun Mo;Yoo, Hye Jung;Kim, Han Chul;Han, Geul Soon
    • The Korean Journal of Nuclear Medicine Technology
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    • v.16 no.2
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    • pp.139-148
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    • 2012
  • Purpose : Since standard solution is the one that knows its exact concentration, the curve of the dissolution has been determined according to the amount of the solution, compared to the amount of the unknown sample. Therefore, the antigen that makes up standard materials should be made in a pure form. The configuration of the standard substance solution in the kit we use is a freeze-dried material, or made and comes as a liquid. Lyophilized reference material is used after dissolving in usually D.W. (Distilled Water), and if the antigen to use is too sensitive, reagents should be freeze-dried. Furthermore, when freeze-dried reference has to be frozen again after being dissolved, it should be kept under $-20^{\circ}C$ until the expiration date according to the reports. Since it is not expressed in the experiment if it is safe or stable to reuse the solution which was dissolved a few times, thus, this time it is tested and evaluated that the changes of the standard solution by freezing and melting several times, and its results and the effectiveness of it were compared to the solution which was kept in a fridge. Materials and Methods : Among Vitro diagnostic kits on the market made by radioimmunoassay, parathyroid hormone (PTH), adrenocorticotropic hormone (ACTH), luteinizing hormone (LH) are made of freeze-dried standard solution and all composed of the same Lot.NO. These hormones melted in D.W. and were separated into three groups. In the first group, melting and freezing were repeated, and in the second group, The solution only for one time use was put into a test tube after melting and freeze it. The third group was kept in the refrigerator. This experiment has been conducted from January to February in 2012. January to 2012. PH test was employed because ph is prone to changing depending on the change of protein. Each group of the standard solution, cpm (counter per minute), and the patient relative concentration values were compared by date, and Through the correlation coefficient and Paired t-test, the significant level of each group was analyzed. Results : ACTH, PTH, LH pH values were too subtle denaturation rather than numerical changes in the protein. In addition, when the standard solution of ACTH, PTH, LH was refrigerated, after 3 days and 7 days, there was a significant difference observed between the solution being kept in a refrigerator and a freezer within a significance level. Conclusion : Standard solution should be kept in a freezer, and being kept in a fridge, it is recommended to use the solution as soon as possible.

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Relationship between Blood Pressure and Impairment of Cognitive Function In Some Rural Residents Aged 60-64 (일부 60-64세 농촌 거주자에서 혈압과 인지기능 장애와의 관계)

  • Lee, Moo-Sik;Chun, Jong-Chan;Lee, Choong-Won
    • Journal of Preventive Medicine and Public Health
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    • v.33 no.2
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    • pp.208-214
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    • 2000
  • Objectives : Face-to-face interviews were conducted to investigate the relationship between blood pressure and the impairment of cognitive function in rural elderly (N=932) aged 60-64 in Dalsung County, April to September in 1996 Methods : Impairment of cognitive function was defined as a score of less than 23 by the Korean version of the Mini-Mental State Examination (MMSEK). Blood pressure was measured once in each subject using a portable automatic sphygmomanometer. Results : By univariate logistic regression on males, no category of systolic blood pressure bore statistical significance. Groups with diastolic blood pressures of, less than 80 mmHg, 90-94 mmHg, and more than 95mmHg had odds ratios of more than one compared with the reference group (80-89 mmHg). This was most significant in the group with blood pressures lower than 80 mmHg, which had a statistically significant odds ratio of 1.68 (95% confidence interval CI; 1.02-2.75). No category of blood pressure was statistically significant in females. Multivariate logistic regression for males, with adjustment for age, educational attainment, smoking, alcoholic drinking, body mass index, atherosclerotic disease, and antihypertensive medication use, did not alter the odds ratios significantly in terms of systolic blood pressure. However, the group with diastolic blood pressure of less than 80 mmHg had an increased odds ratio of 2.01 (95% CI; 1.15-3.52) compared with the reference group. In females, systolic blood pressure did not alter the odds ratio, but the group with a diastolic blood pressure of less than 80 mmHg had a statistically significant odds ratio of 0.57 (95% CI; 0.37-0.89). Conclusions : These results suggest that the relationship between blood pressure and cognitive function status is stronger diastolic than systolic blood pressure and that there is a complex relationship between blood pressure and cognitive function by sex.

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Evaluation of the Efficiency of E. coli O157: H7 Rapid Detection Kit using Immunochromatography (면역크로마토그래피를 이용한 E. coli O157: H7 신속검출 키트의 유효성 평가)

  • Kwak, Hyo-Sun;Lee, Dong-Ha;Moon, Hee-Sook;Park, Jong-Seok;Woo, Gun-Jo;Kim, Chang-Min
    • Journal of Food Hygiene and Safety
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    • v.18 no.3
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    • pp.118-124
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    • 2003
  • For the rapid detection of various pathogenic microorganisms from food sample, various kinds of kits have been developed and commercially available in the markets. With the advantages of speed, accuracy and easiness, the market of these kits has gradually increased for the QC and QA field of food company as well as testing facilities or laboratories. In this study, the characteristics such as the detection limit and the sensitivity of immunochromatographic type of rapid detection kit (Donga Co, Korea, D-kit) for E. coli 0157:H7 developed by monoclonal antibody were examined and also the possibility of application of the kit to food samples was evaluated. The reference kits used for comparison study were Reveal E. coli 0157:H7 (Neogen Co., USA, R-kit) and VIP EHEC kit (Biocontrol Inc., USA, V-kit) occupying major market share. In the detection limit test with the E. coli 0157:H7 reference, both R-kit and D-kit showed a distinct positive reaction in $10^4$/ml and weak positive reaction in $10^3$/ml, whereas V-kit showed a same reaction in 105/ml. Also, it was identified that the culture treated with heat showed more sensitivity than no heat treated culture. The sensitivity test was conducted against 22 isolates of E. coli 0157:H7, 7 strains of non-O157:H7 verotoxin-producing E. coli, 40 strains of E. coli with different O and H antigen type, and 38 strains of non-E. coli Enterobacteriaceae, and all of the test strains except three were showed exactly three were showed exactly the same reaction against three kinds of the tested kits. All the three kinds of kits showed a positive reaction against E. coli O157:H19, E. coli O148:H18 and Salmonella galinarium. We suppose that there might be a similarity in serological property between these three strains and O157:H7. From the test results, it can be concluded that there is (was) no difference between the D-kit developed in this study and R-kit or V-kit based on the detection limit and sensitivity.

Assessment of Environmental Pollution in Korean Stream Sediments by Chemical Analyses and Insect Immune Biomarkers

  • Ryoo, Keon-Sang;Byun, Sang-Hyuk;Hong, Yong-Pyo;Cho, Ki-Jong;Bae, Yeon-Jae;Kim, Yong-Gyun
    • Korean Journal of Environmental Biology
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    • v.26 no.4
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    • pp.330-342
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    • 2008
  • A comprehensive quality survey for PCDDs/PCDFs and coplanar PCBs as well as heavy metals (Cu, Zn, Cd and Pb) in sediments has been investigated in August 2006, Korea. Monitoring was undertaken at five streams representing different surrounding environments throughout Juwang and Gapyeong streams (reference sites), Jungrang stream (dense population site), Ansan stream (mixed small population and industrial site), and Siheung stream (heavy industrial site). The levels of heavy metal in samples were found to be significantly higher in sediment from Siheung stream compared to those of other stream sites. The heavy metal concentrations (dry weight basis) in sediment from Siheung stream were as follows; Cd (3.7 ${\mu}g$/g), Pb (1,295 ${\mu}g$/g), Cu (713.4 ${\mu}g$/g) and Zn (358.1 ${\mu}g$/g). Among 12 coplanar PCBs and 17 PCDDs/PCDFs selected as target compounds in this study, PCB (IUPAC no. 118) and OCDD were the most abundant congeners found in all sediment samples, followed by 1,2,3,4,6,7,8-HpCDD, OCDF and 1,2,3,4,6,7,8HpCDF as well as PCB (IUPAC no. 105). These results were shown to be in the same trend as the sediment samples of other countries. The levels of PCDDs/PCDFs/coplanar PCBs in sediment samples were expressed as concentrations and WHO- TEQ values. The PCDDs/PCDFs/coplanar PCBs concentrations and their WHO-TEQ values in sediment from Siheung stream were remarkably high. The levels detected were 788.16 pg/g and 36.080 pg WHO-TEQ/g dry weight for PCDDs/ PCDFs and 314 pg/g and 0.4189 pg WHO-TEQ/g dry weight for coplanar PCBs, respectively, beyond the safety level of sediment value 20 pg WHO-TEQ/g. Sediment samples of the five streams were also monitored by sensitive biomarkers using insect immune responses: hemocyte-spreading behavior and immune-associated enzyme activities of phospholipase A$_2$ (PLA$_2$) and phenoloxidase. Organic extracts of Siheung and Jungrang sediments significantly interfered with the hemocytespreading behavior, whereas those of Ansan, Gapyeong, and Juwang did not. These organic extracts did not inhibit the PLA$_2$ and phenoloxidase activities. However, phenoloxidase was highly susceptible to exposure to aqueous extracts in all site sediments. In comparison, PLA$_2$ activities of the hemocytes were significantly inhibited only by aqueous extracts of Siheung, Jungrang, and Gapyeong sediments, but not by those of Ansan and Juwang. Despite some disparity between bioand chemical monitoring results, the biomarkers can be recommended as a device warning the contamination of biohazard environmental chemicals because of a fast and inexpensive detection method.

Anthropometric Analysis of Unilateral Cleft Lip Patient (편측성 구순열 환아의 안모 계측 연구)

  • Koh, Kwang-Moo;Leem, Dae-Ho;Baek, Jin-A;Ko, Seung-O;Shin, Hyo-Keun
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.33 no.5
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    • pp.392-400
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    • 2011
  • Purpose: Cleft lip and palate is one of the most frequent hereditary deformities of the maxillofacial region which can arise in facial and jaw abnormalities as well as malocclusion and speech problems. In particular, unilateral cleft lip and palate is characterized by midface deformity resulting in maxillary anterior nasal septal deviation and nasal deformity. The aim of this study is to analyze the facial deformity of untreated unilateral cleft lip patients for contribution to primary cheiloplasty. Methods: Thirty-three patients with unilateral cleft lip and palate were impressioned before operation and facial casts were made. The casts were classified into complete cleft lip and incomplete cleft lip groups and each group were classified into affected side and normal side. Anthropometric reference points and lines were setted up and analysis between points and lines were made. Results and Conclusion: The obtained results were as follows: 1. The intercanthal width had no significant difference between the incomplete and complete cleft lip groups. 2. Cleft width and alar base width were greater in the complete group, and nasal tip protrusion was greater in the incomplete group. 3. Involved alar width and nostril width were greater in the complete group and in both complete and incomplete groups, involved alar width and nostril width were greater than the non-involved side. 4. The lateral deviation of the subnasale was greater in the complete group in both involved and non-involved sides. 5. The nasal laterale was placed inferiorly in both cleft groups. 6. The subnasale was deviated to the non-involved side in both cleft groups. 7. The nose tip was deviated to the non-involved side in both cleft groups and had greater lateral deviation in the complete cleft group. 8. The midpoint of cupid's bow had no vertical difference between complete and incomplete groups, but had a greater lateral deviation in the complete group. 9. In the complete cleft group, correlation between differences in cleft width and nostril width and columella height difference were obtained.

Effect of Construction Joint on Leakage Resistance of Gas in Reinforced Concrete Pressure Vessels (철근콘크리트 압력용기에서 시공이음이 가스의 누설저항에 미치는 영향)

  • Yi, Seong-Tae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.2
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    • pp.87-94
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    • 2017
  • In the nuclear power plant, the steel or polymer liner plates are adopted to prohibit the inner concrete surface from contacting with gas or liquid materials. If there is an accident, the plate may be damaged, and, in this case, concrete shall have the final responsibility to safety requirements. In this paper, an experimental research was carried out to investigate the effects of construction joint and wet and loading conditions on the permeability of concrete. The test results showed that, under a construction joint in the wet condition, leakage of gas pressure has been started from $1kg/cm^2$. However, when there are no construction joints, it is initiated from $2kg/cm^2$. In addition, under the air dried and unloading condition, regardless of with or without the presence of the construction joint, since the gas passage that exist in concrete is constant, leakage has a constant tendency to increase. Finally, under the loading condition, as described in Reference 1, since leakage is inversely proportional to the thickness of the wall, and, considering the wall thickness of the actual plant, it is found that there will not be no problem in the sealing of the gas.

Image Evaluation for A Kind of Patient Fixing Pad in 64 Multi-Channel Detector Computed Tomograph (64 다중채널 검출기 전산화단층촬영에서 환자고정자 재질에 대한 영상평가)

  • Kim, Kee-Bok;Goo, Eun-Hoe
    • Journal of the Korea Convergence Society
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    • v.7 no.1
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    • pp.89-95
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    • 2016
  • The purpose of this experiment intend to evaluate the quality of the image based on the orbit and basal ganglia with high radiosensitivity for the noise, SNR and dose using the five kinds patient fixing pad in brain phantom MDCT(BrillianceTM CT 64 slice, PHILIPS, Netherward). The noise had a higher values in AP than those of others, but the SNR was lower in AP than those of others. The SNR was higher in UP than those of RP, PP, SP and AP. The UP, RP and PP were no statistically significant(p>0.05), whereas it was significant difference between UP, RP, PP and SP, AP(p<0.05). This is causes of the noise difference is generated due to the differences in the radiation absorption dose in accordance with each the component of the absorbed dose level of the detector according to the reference line and each of SOML when the radiation exposured. The CTDIvol(mGy) and DLP of orbit and basal ganglia were 56.95, 911.50, respectively. There is no difference between both mean dose. In conclusion, it is possible to distinguish among a kind of 5 patient fixing pad by using brain phantom MDCT. Overall, patient fixing pad of UP, RP and PP based on a brain phantom MDCT can provide useful information.