图像CT值与管电流、管电压及碘浓度的关系及降低管电压时对比剂的合理用量  

The correlation between CT attenuations and tube current, tube voltage and iodine concentration as well as the percentage of reducing contrast agent volume while reducing tube voltage

作　　者：吕蓉[1] 韩宇欣[1] 孙俊杰[1] 张芳[1] 王迪[1] 李娜[1] 于长路[1] 

机构地区：[1]天津市第三中心医院放射科天津市肝胆疾病研究所天津市人工细胞重点实验室卫生部人工细胞工程技术研究中心,300170

出　　处：《中华放射学杂志》2017年第6期456-459,共4页Chinese Journal of Radiology

摘　　要：目的探讨图像CT值与管电流、管电压及碘浓度的关系以及降低管电压时合理降低对比剂用量的比例。方法配制初始碘浓度为0.5mg/ml，以0.5 mg/ml的递增量达50.0 mg/ml，共100份样本。将样本按顺序装入100个注射器，量均为4 ml，每25个装有样本的注射器为一组，将其用胶带间隔相等距离固定在圆柱形CT校准专用水模上。采用不同管电压（70、80、100、120、140 kV）及管电流（100、200、280 mA），两两结合，共15种扫描方式行轴面扫描。测量不同浓度样本在不同扫描条件下的CT值。采用方差分析比较不同扫描管电流、管电压条件下CT值的差异，采用Pearson线性相关分析评价不同扫描条件下样本浓度和CT值的相关性，并用线性回归得到回归方程及相关系数，根据CT值与浓度的相关方程计算随管电压下降碘浓度下降百分比。结果管电压固定时，不同管电流间样本CT值的差异无统计学意义（P均〉0.05）；管电流固定时，不同管电压间样本CT值的差异均有统计学意义（P均〈0.05）。各种扫描条件下，CT值与样本碘浓度均呈线性相关（r2值为0.953~0.997，P均〈0.01）。管电压由140 kV分别降至120、100、80、70 kV时，碘浓度分别下降15.4%、33.7%、53.4%、64.7%；管电压由120 kV分别降至100、80、70 kV时，碘浓度分别下降21.6%、44.9%、58.2%；管电压由100 kV分别降至80、70 kV时，碘浓度分别下降29.7%、46.7%；当80 kV降至70 kV时，碘含量相应下降24.1%。 结论降低管电压时可以通过减少对比剂用量，来确保CT值不变，从而实现低辐射剂量、低对比剂用量扫描。ObjectiveTo investigate the impact of tube current and tube voltage on CT attenuation, the correlation between CT attenuation and iodine concentration, as well as the percentage of reducing dosage for contrast agent while reducing the tube voltage.MethodsA total of 100 saline solutions with decreasing dilution of contrast medium, in which concentration was between 0.5 to 50.0 mg/ml with the interval of 0.5 mg/ml, was produced. Each of the 25 syringes with a 4 ml sample was fixed on a cylindrical CT calibrated water phantom with an equal distance used the tape. CT scans were performed with a total of 15 scanning methods of the combination of the different tube voltages （70, 80, 100, 140 kV） and tube current （100, 200, 280 mA）. All of the CT attenuations were measured and recorded. The differences of CT attenuations under different scanning tube currents and tube voltages were compared with one-way ANOVA. The Pearson correlation analysis was used to analyze the relationship between CT attenuation and iodine concentration, and linear correlation equations were calculated and shown by regression analysis. According to the equations, the changes of contrast medium dosage were calculated with the changes of tube voltage.ResultsThere was no significant difference in CT attenuations on different tube currents when the tube voltage was fixed （all P〉0.05）, while when the tube current was fixed, the difference of CT attenuations on different tube voltages was statistically significant （all P〈0.05）. Under different scanning conditions, the CT attenuations was linearly related to the iodine concentration （r2 was 0.953 to 0.997, all P〈0.01）. While the tube voltage was reduced from 140 kV to 120 kV, 100 kV, 80 kV, 70 kV, respectively, the iodine concentration of the samples were reduced by 15.4%, 33.7%, 53.4%, 64.7% respectively. While the voltage was reduced from 120 kV to 100 kV, 80 kV, 70 kV, respectively, the iodine concentration were reduced by 21.6%, 44.9%, 58.2%, respectively. While the voltage

关 键 词：体层摄影术 X线计算机 造影剂 辐射剂量 对比研究 

分 类 号：R814.42[医药卫生—影像医学与核医学]