中华放射学杂志
中華放射學雜誌
중화방사학잡지
Chinese Journal of Radiology
2013年
5期
458-461
,共4页
管电压%管电流%CT值%辐射剂量
管電壓%管電流%CT值%輻射劑量
관전압%관전류%CT치%복사제량
Tube voltage%Tube current%CT attenuation%Radiation dose
目的 探讨降低管电流和管电压对CT值的影响,及其辐射剂量降低对图像质量的影响程度.方法 配置不同浓度对比剂样本共113个,在15种不同扫描条件下进行CT扫描.测量和记录CT值及标准差,分析改变管电流和管电压对CT值测量的影响,并计算对应关系.记录CT容积剂量指数(CTDIvol),计算15种扫描条件下的辐射剂量.不同管电压和管电流下CT值差异比较采用方差分析和Kruskal-Wallis秩和检验,不同管电压下CT值对应关系及管电压和管电流对辐射剂量和图像质量的影响程度分析采用相关性分析.结果 管电压固定时不同管电流间(250、200、150、100和50 mA)的CT值差异均无统计学意义(F值分别为0.001、0.008、0.075,P均＞0.05).管电流固定时,不同管电压间(120、100和80 kV)的CT值差异均具有统计学意义(H值分别为17.906、17.906、13.527、20.124、23.563,P均＜0.05).计算不同管电压下同一样本CT值的对应关系:CT值100 kV=1.561×CT值120kV+4.0818,CT值80kV=1.2131 ×CT值120 kV+0.9283.分析不同管电压下辐射剂量对图像噪声的影响程度,并确立相关性方程:N120kv=-5.9771Ln(D120kV)+25.412,N100kv=-10.544Ln(D100 kV)+36.262,N80 kv=-25.326Ln(D80 kv)+62.816.计算噪声值关键点,证明根据所需图像噪声值(11.2和13.9),可以指导扫描条件,在一定条件下应用低管电压,高管电流可以降低辐射剂量.结论 管电压对CT值测量有影响,根据所需图像噪声值调整扫描条件,在一定条件下应用低管电压,高管电流可以降低辐射剂量.改变管电压后造成的CT值变化,可依据不同管电压下CT值对应关系进行校准.
目的 探討降低管電流和管電壓對CT值的影響,及其輻射劑量降低對圖像質量的影響程度.方法 配置不同濃度對比劑樣本共113箇,在15種不同掃描條件下進行CT掃描.測量和記錄CT值及標準差,分析改變管電流和管電壓對CT值測量的影響,併計算對應關繫.記錄CT容積劑量指數(CTDIvol),計算15種掃描條件下的輻射劑量.不同管電壓和管電流下CT值差異比較採用方差分析和Kruskal-Wallis秩和檢驗,不同管電壓下CT值對應關繫及管電壓和管電流對輻射劑量和圖像質量的影響程度分析採用相關性分析.結果 管電壓固定時不同管電流間(250、200、150、100和50 mA)的CT值差異均無統計學意義(F值分彆為0.001、0.008、0.075,P均＞0.05).管電流固定時,不同管電壓間(120、100和80 kV)的CT值差異均具有統計學意義(H值分彆為17.906、17.906、13.527、20.124、23.563,P均＜0.05).計算不同管電壓下同一樣本CT值的對應關繫:CT值100 kV=1.561×CT值120kV+4.0818,CT值80kV=1.2131 ×CT值120 kV+0.9283.分析不同管電壓下輻射劑量對圖像譟聲的影響程度,併確立相關性方程:N120kv=-5.9771Ln(D120kV)+25.412,N100kv=-10.544Ln(D100 kV)+36.262,N80 kv=-25.326Ln(D80 kv)+62.816.計算譟聲值關鍵點,證明根據所需圖像譟聲值(11.2和13.9),可以指導掃描條件,在一定條件下應用低管電壓,高管電流可以降低輻射劑量.結論 管電壓對CT值測量有影響,根據所需圖像譟聲值調整掃描條件,在一定條件下應用低管電壓,高管電流可以降低輻射劑量.改變管電壓後造成的CT值變化,可依據不同管電壓下CT值對應關繫進行校準.
목적 탐토강저관전류화관전압대CT치적영향,급기복사제량강저대도상질량적영향정도.방법 배치불동농도대비제양본공113개,재15충불동소묘조건하진행CT소묘.측량화기록CT치급표준차,분석개변관전류화관전압대CT치측량적영향,병계산대응관계.기록CT용적제량지수(CTDIvol),계산15충소묘조건하적복사제량.불동관전압화관전류하CT치차이비교채용방차분석화Kruskal-Wallis질화검험,불동관전압하CT치대응관계급관전압화관전류대복사제량화도상질량적영향정도분석채용상관성분석.결과 관전압고정시불동관전류간(250、200、150、100화50 mA)적CT치차이균무통계학의의(F치분별위0.001、0.008、0.075,P균＞0.05).관전류고정시,불동관전압간(120、100화80 kV)적CT치차이균구유통계학의의(H치분별위17.906、17.906、13.527、20.124、23.563,P균＜0.05).계산불동관전압하동일양본CT치적대응관계:CT치100 kV=1.561×CT치120kV+4.0818,CT치80kV=1.2131 ×CT치120 kV+0.9283.분석불동관전압하복사제량대도상조성적영향정도,병학립상관성방정:N120kv=-5.9771Ln(D120kV)+25.412,N100kv=-10.544Ln(D100 kV)+36.262,N80 kv=-25.326Ln(D80 kv)+62.816.계산조성치관건점,증명근거소수도상조성치(11.2화13.9),가이지도소묘조건,재일정조건하응용저관전압,고관전류가이강저복사제량.결론 관전압대CT치측량유영향,근거소수도상조성치조정소묘조건,재일정조건하응용저관전압,고관전류가이강저복사제량.개변관전압후조성적CT치변화,가의거불동관전압하CT치대응관계진행교준.
Objective To assess the influence of tube current and tube voltage on the CT attenuation,radiation dose,and image quality.Methods A total of 113 saline solutions with decreasing dilution of contrast medium (370 mg I/ml) was produced.MDCT scan was performed with 15 series of different settings of tube current and tube voltage.CT attenuations with 15 series of different settings were all measured,and influence of tube current and tube voltage on CT attenuations was analyzed.CT dose index (CTDIvol) was recorded.The CT attenuations with different tube voltage and current were compared with one-way ANOVA and Kruskal-Wallis rank sum test.The correlation of CT attenuation with different tube voltage and the influence of tube voltage and current on radiation dose and image quality were tested by correlation analysis.Results Tube current (250,200,150,100,and 50 mA) had no significant effect on CT attenuation (F =0.001,0.008,0.075,P ＞ 0.05),while tube voltage (120,100,and 80 kV) had significant effect (H =17.906,17.906,13.527,20.124,23.563,P ＜ 0.05).The correlation between CT attenuation and tube voltage was determined with equation:CT attenuatio N100 kV =1.561 × CT attenuatio N120kv + 4.0818,CT attenuatio N80kV =1.2131 × CT attenuatio N120kv + 0.9283.The influence of tube voltage on radiation dose and image quality was also analyzed,and equations were also obtained:N120 kV =-5.9771Ln(D120 kV) + 25.412,N100 kV =--10.544Ln (D100 kV) + 36.262,N80 kV =-25.326Ln(D80kv) +62.816.According to the results of relationship among CT attenuation,radiation dose,and image quality,lower tube voltage with higher tube current can reduce the radiation dose.Conclusions Lower tube voltage can reduce the radiation dose.However,CT attenuation was influenced,and correction should be done with the equations.
