Study On Impact Of Coronary CT Angiography On DNA Double Strand Breaks In Peripheral Blood Lymphocytes

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The Impact of Radiation dose from Coronary CTA on human lymphocyte DNA double strand breaksPurpose:To determine the effect of radiation dose on DNA double strand breaks(DSBs)in peripheral blood lymphocytes using immunofluorescence microscopy and flow cytometry.Materials and methods:A total of 180 patients undergoing CCTA were included in the study.Patients were divided into 3 groups,including 6 subgroups[A(A1,A2),B(B1,B2),and C(C1,C2)]based on effective dose(approximately 1,3 and 5 mSv),There were 60 patients in each large group and 30 patients in each subgroup,with demographic characteristics[age,gender,height,weight,body mass index(BMI)]and effective dose of two subgroups in the same large group matched.Total of 2 ml blood was taken from peripheral venous blood before and 20 minutes after the examination.After separation of lymphocytes by density gradient centrifugation,lymphocytes of patients in the Al,B1,and C1 groups were stained by immunofluorescence of ?-H2AX antibody,being analyzed using immunofluorescence microscopy.The lymphocytes from patients in the A2,B2,and C2 groups were incubated with CD3 antibody and y-H2AX antibody.The geometric mean of fluorescence intensity(MFI)of y-H2AX protein in CD3-positive T lymphocytes was measured by flow cytometry.The chi-square test was used for gender comparison between groups and between subgroups.Comparison of patient demographic characteristics(except for gender)was performed using independent sample t-test and one-way analysis of variance(ANOVA).The ?-H2AX foci and MFI before and after CCTA were compared using the Wilcoxon signed rank sum test;Kruskal-Wallis rank sum test was used for comparison of changes in DNA DSBs between groups and subgroups.P<0.05 was considered statistically significant.Results:There was no significant difference in demographic characteristics and effective dose between A1 and A2,B1 and B2,and C1 and C2 groups(all P>0.05).After CCTA examination,the fluorescence foci of y-H2AX in peripheral blood lymphocytes of group A1,B1,and C1 increased by 0.08,0.09,and 0.11 foci per cell(all P<0.05),respectively.The MFI of y-H2AX in CD3 positive T lymphocyte of group A2,B2 and C2 increased by 7.34,9.53,and 12.74(all P<0.05),respectively.Both with the comparison between A1,B1,and C1 groups and between A2,B2,and C2 groups,the increasing level of ?-H2AX foci in lymphocytes and the MFI of?-H2AX in CD3 positive T lymphocytes decreased with radiation dose,but without statistical significance(all P>0.05).Conclusion:In the range of 1-5mSv,reducing radiation dose of CCTA would not cause decreasing degree of DNA double strand breaks..Part ? Impact of Coronary CT Angiography Tube Voltage on Human Lymphocyte DNA Double Strand BreaksPurpose:To evaluate effect of coronary CT angiography(CCTA)tube voltage on DNA double strand breaks(DSBs)in peripheral blood lymphocytes using immunofluorescence microscopy and fow cytometryMaterials and methods:A total of 240 patients undergoing CCTA were included in this study.They were randomly divided into 4 major groups,including 8 subgroups,A(A1,A2),B(B1,B2),C(C1,C2),and D(D1,D2).There were 60 patients in each major group and 30 patients in each subgroup.Four groups of patients received CCTA examinations with tube voltage of 120 kV,100 kV,80 kV,and 70 kV,respectively.Except for tube voltage,the scan parameters remained consistent,with,the demographic characteristics[age,gender,height,weight,body mass index(BMI)]of the two subgroups in the same major group matched,BMM of included patients in this study was less than 25Kg/m2.Two ml peripheral venous blood was collected for every patient before and 20 minutes after examinations,respectively.After separation of lymphocytes by density gradient centrifugation,samples of patients in A1,B1,C1,and D1 groups were stained with y-H2AX antibody,and analyzed using immunofluorescence microscopy.The lymphocyte samples from patients in A2,B2,C2,and D2 groups were incubated with CD3 antibody and y-H2AX antibody,and the geometric mean of fluorescence intensity(MFI)of y-H2AX in CD3 positive T lymphocytes before and after the examination was measured by flow cytometry.The chi-square test was used for gender comparison between groups and between subgroups.Comparison of patient demographic characteristics(except for gender)was performed using independent sample t-test and one-way analysis of variance.The y-H2AX foci and MFI before and after CCTA were compared using the Wilcoxon signed rank sum test;Kruskal-Wallis rank sum test was used for comparison of changes in DNA DSBs between groups and subgroups.P<0.05 was considered statistically significant.Results:There was no significant difference in demographic characteristics and radiation dose between A1 and A2,B1 and B2,C1 and C2 and D1 and D2 groups(all P>0.05).After CCTA examination,the fluorescence foci of ?-H2AX in peripheral blood lymphocytes of group Al,B1,C1,and D1 increased by 0.13,0.09,0.07,and 0.06 foci per cell(all P<0.05),respectively.The MFI of y-H2AX in CD3 positive T lymphocytes of group A2,B2,C2,and D2 increased by 21.26,9.13,8.10,and 7.13(all P<0.05),respectively.As the tube voltage decreased,the increased level of?-H2AX foci in lymphocyte and the MFI of y-H2AX in CD3 positive T lymphocytes both decreased.The increased level of y-H2AX foci in the A1(120kV)group was higher than those from the three groups significantly(all P<0.05),but there was no significant difference among three group B1,C1,and D1(all P>0.05)The MFI of?-H2AX in CD3 positive T lymphocytes changes consistently with the trend obtained by immunofluorescence microscopyConclusion:With tube voltage decreased from 120kV to 100kV,80kV or 70kV,the degree of DNA damage decreased significantly.However,DNA damage level would not decrease significantly with tube voltage decreased from 100kV to 70kV.