目的:探讨iDose4迭代重建在冠状动脉CT血管造影(coronary CT angiography,CCTA)中的应用价值。方法:选择冠心病患者124例,均行CT扫描iDose4迭代重建与滤波反投影(filtered back-projection,FBP)重建。iDose4迭代重建患者依体质量指数(bo...目的:探讨iDose4迭代重建在冠状动脉CT血管造影(coronary CT angiography,CCTA)中的应用价值。方法:选择冠心病患者124例,均行CT扫描iDose4迭代重建与滤波反投影(filtered back-projection,FBP)重建。iDose4迭代重建患者依体质量指数(body mass index,BMI)进行分组,BMI≥20 kg/m2为迭代组1(135 k V),共56人,BMI<20 kg/m2为迭代组2(110 k V),共68人;FBP组均采用110 k V管电压进行扫描。分别对信噪比(signal noise ratio,SNR)、对比噪声比(contrast to noise ratio,CNR)及图像质量进行比较分析。结果:迭代组1与FBP组的SNR、CNR、辐射剂量及图像质量评分差异均存在且差异具有统计学意义(P<0.05)。迭代组2与FBP组的CNR及辐射剂量差异均存在且差异具有统计学意义(P<0.05),SNR、图像质量评分差异不具有统计学意义(P>0.05)。结论:低压iDose4重建法在64排CCTA中辐射剂量小且图像质量好,值得在临床中推广应用。展开更多
The influence of low tube voltage in dual source CT（DSCT） coronary artery imaging on image quality and radiation dose and its application value in clinical practice were investigated. Totally, 300 cases of chest pai...The influence of low tube voltage in dual source CT（DSCT） coronary artery imaging on image quality and radiation dose and its application value in clinical practice were investigated. Totally, 300 cases of chest pain with low body mass index（BMI 〈18.5 kg/m2） subjected to DSCT coronary artery imaging were prospectively enrolled. The heart rate in all patients were greater than 65/min. The retrospective ECG gated scanning mode and simple random sampling method were used to assign the patients into groups A, B and C（n=100 each）. The patients in groups A, B and C experienced 120-, 100-, and 80-kV tube voltage imaging respectively, and the image quality was evaluated. The CT volume dose index（CTDIvol） and dose length product（DLP） were recorded, and the effective dose（ED） was calculated in each group. The image quality scores and radiation doses in groups were compared, and the influence of tube voltage on image quality and radiation dose was analyzed. The results showed that the excellent rate of image quality in groups A, B and C was 95.69%, 94.72% and 96.33% respectively with the difference being not statistically significant among the three groups（P〉0.05）. The CTDIvol values in groups A, B and C were 51.35±12.21, 21.28±7.13 and 6.34±3.34 mGy, respectively, with the difference being statistically significant（P〈0.05）. The ED values in groups A, B and C were 9.27±1.63, 4.56±2.29 and 2.29±1.69 mSv, respectively, with the difference being statistically significant（P〈0.05）. It was suggested that for the patients with low BMI, the application of DSCT coronary artery imaging with low tube voltage can obtain satisfactory image quality, and simultaneously, significantly reduce the radiation dose.展开更多
The American College of Radiology opened the computed tomography (CT) dose index registry (DIR) for general participation by all facilities in 2011. For each CT examination, data on volume CT dose index (CTDIvol), dos...The American College of Radiology opened the computed tomography (CT) dose index registry (DIR) for general participation by all facilities in 2011. For each CT examination, data on volume CT dose index (CTDIvol), dose-length product (DLP), and, for body examinations, size-specific dose estimate (SSDE) were collected. However, effective dose is not estimated in DIR. The primary objective of this study was to estimate k-factor profile in detail at various scan positions with modified the ImPACT CT patient dosimetry. A tool that easily estimates the k-factor of suitable scan areas is essential for practical dose estimation in the DIR. We evaluated k-factor (effective dose/ DLP) profiles between a medical international radiation dose-five (MIRD-5) phantom positions using aImPACT software. As a result of this study, practicality of the k-factor profile method in clinical use was clarified. We speculate that a flexible k-factor improves the appropriateness of the E in hospital settings.展开更多
The magnitude of radiation dose imparted to patients who underwent Head Computed Tomography examination in a large tertiary hospital in South-Southern Nigeria has been estimated. CT-ExPO dosimetry software was used to...The magnitude of radiation dose imparted to patients who underwent Head Computed Tomography examination in a large tertiary hospital in South-Southern Nigeria has been estimated. CT-ExPO dosimetry software was used to determine the effective and organ doses to the head region of 40 adult patients. Scanning parameters were retrieved from the CT monitor for both contrast-enhanced and non-contrast head CT examinations. The tube potential ranged from 100 kVp to 120 kVp, while the mAs ranged from 127 mAs to 202 mAs. The mean values of the volume Computed Tomography Dose Index (CTDIvol) and Dose Length Product (DLP) for the contrast-enhanced Head CT examination were 166.4 ± 39.6 mGy and 3568.6 ± 756.1 mGy·cm, respectively, while for the non-contrast examination they were 86.6 ± 30.4 mGy and 2102.3 ± 870.3 mGy·cm, respectively. The effective doses were higher for the contrast-enhanced study than for the non-contrast study by a factor of 1.6. Results were compared with the European Union reference doses and other published data and were found to be higher. Doses to the organs which comprise of brain, red bone marrow, thyroid and eye lens were also estimated. The high variation in the doses in this study may be due to differences in imaging protocols such as large range of mAs and scan lengths and also the algorithm of the scanner.展开更多
目的:比较容积CT剂量指数(volume CT dose index,CTDI_(VOL))及基于水当量直径的体型特异性剂量估计值(size-specific dose estimate based on water equivalent diameter,SSDE_(WED))在衡量儿童头颅CT辐射剂量中的差异性,并分析CTDI_(V...目的:比较容积CT剂量指数(volume CT dose index,CTDI_(VOL))及基于水当量直径的体型特异性剂量估计值(size-specific dose estimate based on water equivalent diameter,SSDE_(WED))在衡量儿童头颅CT辐射剂量中的差异性,并分析CTDI_(VOL)、SSDE_(WED)与曝光量、水当量直径(water equivalent diameter,WED)的相关性,以为临床检查中儿童头颅CT辐射剂量衡量提供参考。方法:回顾性分析2021年1—12月于某院进行头颅CT检查的1297例患儿的临床资料,根据年龄将患儿分为≤1个月组、>1个月~4岁组、>4~10岁组、>10~15岁组。记录患儿的曝光量、年龄、CTDI_(VOL)、剂量长度乘积,并计算WED、转换因子及SSDE_(WED)。比较CTDI_(VOL)与SSDE_(WED)的差异;建立CTDI_(VOL)、SSDE_(WED)与曝光量、WED的回归模型,并采用Pearson分析CTDI_(VOL)、SSDE_(WED)与曝光量、WED之间的相关性;对比国内诊断参考水平(diagnostic reference level,DRL)、欧盟DRL及本医疗机构诊断参考水平(local diagnostic reference level,LDRL)的差异。采用SPSS 25.0统计学软件进行分析。结果:患儿头颅CT的CTDI_(VOL)为(9.22±1.63)mGy,SSDE_(WED)为(8.14±0.84)mGy,CTDI_(VOL)较SSDE_(WED)高13.27%,差异有统计学意义(t=47.66,P<0.001)。CTDI_(VOL)、SSDE_(WED)与曝光量、WED均呈正相关关系(P<0.001);CTDI_(VOL)、SSDE_(WED)与曝光量、WED回归模型拟合性较强(R^(2)为0.58~0.99)。与国内DRL及欧盟DRL比较,LDRL均处于较低水平。结论:在儿童头颅CT辐射剂量衡量中,相较于CTDI_(VOL),SSDE_(WED)对辐射剂量的衡量更准确。同时定期对医疗机构的DRL值进行统计更新并优化检查参数,是减少辐射剂量的重要方式。展开更多
文摘目的:探讨iDose4迭代重建在冠状动脉CT血管造影(coronary CT angiography,CCTA)中的应用价值。方法:选择冠心病患者124例,均行CT扫描iDose4迭代重建与滤波反投影(filtered back-projection,FBP)重建。iDose4迭代重建患者依体质量指数(body mass index,BMI)进行分组,BMI≥20 kg/m2为迭代组1(135 k V),共56人,BMI<20 kg/m2为迭代组2(110 k V),共68人;FBP组均采用110 k V管电压进行扫描。分别对信噪比(signal noise ratio,SNR)、对比噪声比(contrast to noise ratio,CNR)及图像质量进行比较分析。结果:迭代组1与FBP组的SNR、CNR、辐射剂量及图像质量评分差异均存在且差异具有统计学意义(P<0.05)。迭代组2与FBP组的CNR及辐射剂量差异均存在且差异具有统计学意义(P<0.05),SNR、图像质量评分差异不具有统计学意义(P>0.05)。结论:低压iDose4重建法在64排CCTA中辐射剂量小且图像质量好,值得在临床中推广应用。
基金supported by the Natural Science Foundation of Hubei Province,China(No.2012FKB02443)
文摘The influence of low tube voltage in dual source CT（DSCT） coronary artery imaging on image quality and radiation dose and its application value in clinical practice were investigated. Totally, 300 cases of chest pain with low body mass index（BMI 〈18.5 kg/m2） subjected to DSCT coronary artery imaging were prospectively enrolled. The heart rate in all patients were greater than 65/min. The retrospective ECG gated scanning mode and simple random sampling method were used to assign the patients into groups A, B and C（n=100 each）. The patients in groups A, B and C experienced 120-, 100-, and 80-kV tube voltage imaging respectively, and the image quality was evaluated. The CT volume dose index（CTDIvol） and dose length product（DLP） were recorded, and the effective dose（ED） was calculated in each group. The image quality scores and radiation doses in groups were compared, and the influence of tube voltage on image quality and radiation dose was analyzed. The results showed that the excellent rate of image quality in groups A, B and C was 95.69%, 94.72% and 96.33% respectively with the difference being not statistically significant among the three groups（P〉0.05）. The CTDIvol values in groups A, B and C were 51.35±12.21, 21.28±7.13 and 6.34±3.34 mGy, respectively, with the difference being statistically significant（P〈0.05）. The ED values in groups A, B and C were 9.27±1.63, 4.56±2.29 and 2.29±1.69 mSv, respectively, with the difference being statistically significant（P〈0.05）. It was suggested that for the patients with low BMI, the application of DSCT coronary artery imaging with low tube voltage can obtain satisfactory image quality, and simultaneously, significantly reduce the radiation dose.
文摘The American College of Radiology opened the computed tomography (CT) dose index registry (DIR) for general participation by all facilities in 2011. For each CT examination, data on volume CT dose index (CTDIvol), dose-length product (DLP), and, for body examinations, size-specific dose estimate (SSDE) were collected. However, effective dose is not estimated in DIR. The primary objective of this study was to estimate k-factor profile in detail at various scan positions with modified the ImPACT CT patient dosimetry. A tool that easily estimates the k-factor of suitable scan areas is essential for practical dose estimation in the DIR. We evaluated k-factor (effective dose/ DLP) profiles between a medical international radiation dose-five (MIRD-5) phantom positions using aImPACT software. As a result of this study, practicality of the k-factor profile method in clinical use was clarified. We speculate that a flexible k-factor improves the appropriateness of the E in hospital settings.
文摘The magnitude of radiation dose imparted to patients who underwent Head Computed Tomography examination in a large tertiary hospital in South-Southern Nigeria has been estimated. CT-ExPO dosimetry software was used to determine the effective and organ doses to the head region of 40 adult patients. Scanning parameters were retrieved from the CT monitor for both contrast-enhanced and non-contrast head CT examinations. The tube potential ranged from 100 kVp to 120 kVp, while the mAs ranged from 127 mAs to 202 mAs. The mean values of the volume Computed Tomography Dose Index (CTDIvol) and Dose Length Product (DLP) for the contrast-enhanced Head CT examination were 166.4 ± 39.6 mGy and 3568.6 ± 756.1 mGy·cm, respectively, while for the non-contrast examination they were 86.6 ± 30.4 mGy and 2102.3 ± 870.3 mGy·cm, respectively. The effective doses were higher for the contrast-enhanced study than for the non-contrast study by a factor of 1.6. Results were compared with the European Union reference doses and other published data and were found to be higher. Doses to the organs which comprise of brain, red bone marrow, thyroid and eye lens were also estimated. The high variation in the doses in this study may be due to differences in imaging protocols such as large range of mAs and scan lengths and also the algorithm of the scanner.
