• Title/Summary/Keyword: minimum chi-square method

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Breast Imaging Using Electrical Impedance Tomography: Correlation of Quantitative Assessment with Visual Interpretation

  • Zain, Norhayati Mohd;Chelliah, Kanaga Kumari
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.3
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    • pp.1327-1331
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    • 2014
  • Background: Electrical impedance tomography (EIT) is a new non-invasive, mobile screening method which does not use ionizing radiation to the human breast; allows conducting quantitative assessment of the images besides the visual interpretation. The aim of this study was to correlate the quantitative assessment and visual interpretation of breast electrical impedance tomographs and associated factors. Materials and Methods: One hundred and fifty mammography patients above 40 years and undergoing EIT were chosen using convenient sampling. Visual interpretation of the images was carried out by a radiologist with minimum of three years experience using the breast imaging - electrical impedance (BI-EIM) classification for detection of abnormalities. A set of thirty blinded EIT images were reinterpreted to determine the intra-rater reliability using kappa. Quantitative assessment was by comparison of the breast average electric conductivity with the norm and correlations with visual interpretation of the images were determined using Chi-square. One-way ANOVA was used to compare the mean electrical conductivity between groups and t-test was used for comparisons with pre-existing Caucasians statistics. Independent t-tests were applied to compare the mean electrical conductivity of women with factors like exogenous hormone use and family history of breast cancer. Results: The mean electrical conductivity of Malaysian women was significantly lower than that of Caucasians (p<0.05). Quantitative assessment of electrical impedance tomography was significantly related with visual interpretation of images of the breast (p<0.05). Conclusions: Quantitative assessment of electrical impedance tomography images was significantly related with visual interpretation.

Utility of Water Intake to Reduce Stomach's Additional Shooting in PET/CT Test (PET/CT 검사에서 Stomach의 추가 촬영을 줄이기 위한 수분 섭취의 유용성)

  • Lee, Seung-Hwan;Bae, Seong-Bok;Jeong, Byeong-Gon;Lee, Gyu-Chan;Lee, Gwang-Cheol;Bae, Won-Gyu
    • The Korean Journal of Nuclear Medicine Technology
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    • v.15 no.1
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    • pp.81-85
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    • 2011
  • Purpose: With the introduction of PET since 1994, test methods have made rapid progress. Accordingly, the studies on the diagnosis and treatment of cancer as well as treatment response evaluation PET test are useful. However, it is difficult to divide stomach lesions and secretion. The purpose of this study is to reduce additional shooting by dividing lesions and secretion of stomach. Materials and Method: This study aiming at total 228 cancer patients was conducted from Aug 18 to Sep. 10, 2010. Among them, 115 patients had a test without water intake before shooting from Aug. 8 to 31 and 113 had a test after drinking 500 cc water right before shooting from Sep. 1 to 10 The Discovery ST PET/CT (GE Healthcare, USA) was used, and pearson's chi-square test was conducted to analyze significance through SPSS (Ver.18). Results: Among the total 228 cancer patients, there were 115 who had a test without water intake before shooting, 89 who had no double additional shooting, 13 who had stomach additional shooting and 13 who had other additional shooting. In addition, 109 had no additional shooting among 113 who had a test after taking 500 cc water, 1 had stomach additional shooting and 3 had other additional shooting. According to the findings above, the patients who had a test without water intake show reduced additional shooting, but for more exact significance, pearson's Chi-square test was carried out and the significance percentage was 0.001 that is smaller than 0.05, which means two groups have a significant relationship. As the minimum expectation frequency was 6.94 and there was no expectation frequency smaller than 5, so that it doesn't need to carry out pearson's exact verification. Conclusion: The above analysis has found that if one drinks 500cc water before the test, not only stomach additional shooting but also other additional shooting can be dramatically reduced, and test delay can be also reduced.

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Fabrication and Ionic Current Rectification Characteristics of Biomimetic Aluminum Oxide Membrane (생체모방형 비대칭 나노채널을 갖는 산화알루미늄 분리막 제조 및 이온 정류 특성)

  • Jung, Jaehoon;Kim, Jongyoung;Choi, Kiwoon;Lee, Joonho;Kang, Il-suk;Ahn, Chi-won;Cho, Churl-Hee
    • Membrane Journal
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    • v.30 no.3
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    • pp.181-189
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    • 2020
  • In the present study, a biomimetic alumina membrane was fabricated by using selenic acid as an electrolyte to overcome the asymmetry limit of the square pulse anodization process. The prepared membrane has conical channels with a minimum diameter of 10 nm, a maximum diameter of 50 nm, and a length of 5 ㎛. The rectification property was higher than membranes fabricated by sulfuric acid. It showed 2.9 times larger current at +1 V than -1 V. Also, the membrane, which sulfonic acid group was introduced by surface modification, showed 4.2 times larger rectification property at -1 V than +1 V. Theoretical verifications were supported by the numerical analyses of 2D models. The results of the present study present a convenient method to fabricate two type membranes with different rectification properties and are expected to be used to control ion transport.