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  • 28 June 2003 Volume 12 Issue 2
      
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  • The Analysis of Distribution of the Chromosome Aberration Breakpoints from Medical Diagnostic X-ray Workers
    WANG Qin, LI Jin, TANG Wei-sheng, et al
    2003, 12(2): 65-66. https://doi.org/10.13491/j.cnki.issn.1004-714x.2003.02.001
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    Objective To analyze the distribution of the chromosome aberration breakpoints from medical diagnostic X-ray workers.Methods The breakpoints of lymphocyte chromosomes are analyzed using G-banding.Results There are 146 breakpoints among 3 545 metaphase in 37 cases of X-ray workers.There are statistically significant differences between observed values and expected values (χ2=42.82, df=23, P < 0.01).There are 17 breakpoints among 908 metaphase in 10 controls.There are not statistically significant differences between observed values and expected values (P >0.05).Conclusion The chromosome aberration breakpoints of medical diagnostic X-ray workers are non-random.The observed values of breakpoint numbers are higher than those of the expected values in 7 and 14 chromosomes (P < 0.05)
  • Established Curves of Relationships between Radiation Dose and Chromosome Aberrations Induced by Heavy Ion in Human Peripheral Blood Lymphocytes in Vitro
    BAI Yu-shu, HUANG Qi-long, MA Jian-feng, et al
    2003, 12(2): 67-69. https://doi.org/10.13491/j.cnki.issn.1004-714x.2003.02.002
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    Objective To established the curves of relationships between radiation dose and chromosome aberrations induced by heavy ion in human peripheral blood lymphocytes in vitro.Methods Heparinized whole blood samples were exposed to heavy ion 12C.Radiations doses were from 1.0 Gy to 8.0 Gy to 8.0 Gy.Dose rate was 3.0 Gy/min.Unstable chromosome aberrations including acentric fragments, minutes, acentric rings, dicentrics and cenric rings ("dic+r") were scored.Results Chromosome aberrations ("dic+r") induced by heavy ion 12C had a good dose-response relationships.Fitting the best regression equation was Y=0.858503D+0.3615×10-2D2.Conclusion When human blood irradiated by heary ion 12C within 0~8.0 Gy, the best mathematical model of chromosome aberrations ("dic+r") was Y=bD+cD2.
  • Analysis of Dose Distribution to Obtain the Optimum Tumor Control Probability In Radiotherapy
    Ju Yong-jian, Chen Mei-hua, Zhang Liang-an, et al
    2003, 12(2): 70-71. https://doi.org/10.13491/j.cnki.issn.1004-714x.2003.02.004
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    Objective To analyze what kind of dose distribution can lead to the optimum tumor control probability (TCP).Methods When the total absorbed energy was defined, with the proposed TCP model and the method of Lagrange multiplier, the condition which can cause the optimum TCP will be derived.With the assumed values of biological parameters, the curves of the relationship between TCP and the averaged dose in the tumor for the uniform or optimum dose distribution will be shown respectively by calcultion.Results When the values of biological parameters are not uniform in the tumor, the TCP and average dose relationship curve of optimum dose distribution is better than that of uniforn dose distribution.Conclusion The dose distribution that can cause the optimum TCP is related to the distribution of the biological parameter values.
  • Fractional Absorption in Gastrointestinal Tract of 232Th by Ingestion for Chinese Man
    LIU Qing-fen and ZHU Hong-da
    2003, 12(2): 72-73. https://doi.org/10.13491/j.cnki.issn.1004-714x.2003.02.005
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    Objective To estimate fractional absorption in gastrointestinal tract (f1) of 232Th by ingestion for the Chinese male adults.Methods According to f1 calculation method in literature and results of Th concentrations in dietary foods and organ or tissues for the Chinese male abults, obtained in recent years, f1 values were estimated from the median and mean Th concentrations and compared each other.Results The f1 value from the median and mean Th concentrations was 0.000 48 and 0.000 28 respectively.Conclusion The f1 of 232Th by ingestion for the Chinese male adults should be adopted as 0.000 48, being lower than estimated result from the world reference concentrations in UNSCEAR 2000 Report, but quite near to the relevant reported value from Asian countries, such as India or Japan, and supporting the latest recommended value 0.000 5 by ICRP too.