摘要
目的探讨自动管电压(ATVS)联合管电流自动调制(ATCM)技术在胸腹部CT扫描中的应用价值。方法分别于女性胸腹体模CDPR2背部放置不同厚度水膜,并分为A(无水膜)、B(附加1cm厚水膜)、C(附加3cm厚水膜)、D(附加7cm厚水膜)组。采用ATVS联合ATCM及不同噪声指数(NI=8.0、9.0、10.0、11.0、12.0、15.0、17.5、20.0、25.0)分别对4组体模进行扫描;再采用管电压120kV联合ATCM及NI=12.0分别对4组体模进行扫描。计录噪声(SD),计算SNR、有效剂量(ED),并对图像质量进行主观评分。结果 ATVS联合ATCM扫描时,对于相同NI值,随着水膜厚度的增加,管电压增高;对于同一体模,随着NI值的降低,管电压增高。ATVS联合ATCM扫描A、B、C、D组体模时,ED和SNR与NI值均呈高度负相关(r=-0.85、-0.87、-0.92、-0.96,-0.87、-0.89、-0.91、-0.91,P均<0.05),SD与NI值均呈高度正相关(r=0.97、0.98、0.98、0.98,P均<0.05)。NI=12.0时,4组体模图像的主观评分均≥4分。ATVS联合ATCM扫描A、B、C组的ED较管电压120kV联合ATCM及NI=12.0扫描分别降低了20.74%(0.45mSv/2.17mSv)、19.19%(0.52mSv/2.71mSv)、7.38%(0.27mSv/3.66mSv),且上纵隔、心脏和肝脏的SD值差异均无统计学意义(P>0.05);A、B组上纵隔、心脏和肝脏的SNR差异均有统计学意义(P均<0.05);C组上纵隔、心脏和肝脏的SNR差异无统计学意义(P>0.05);D组ED增加了31.05%(1.45mSv/4.67mSv),上纵隔、心脏和肝脏的SNR分别增加了29.88%(1.73/5.79)、32.75%(1.67/5.10)、22.90%(1.01/4.41)。结论 ATVS联合ATCM在胸腹部CT扫描时,可获得较高质量的图像,并显著降低辐射剂量。
Objective To investigate the application value of automatic tube voltage selection （ATVS） combined with automatic tube current modulation （ATCM） technology in thorax and abdomen CT scanning. Methods The female thora- coabdominal phantom CDPR2 was covered by different thickness water film on the back： group A, covered with no water film; group B, covered with 1 cm thickness water film; group C, covered with 3 cm thickness water film; group D, covered with 7 cm thickness water film. Four groups were scanned by ATVS combined with ATCM under different noise indexes （NI, NI=8.0, 9.0, 10.0, 11.0, 12.0, 15.0, 17.5, 20.0, 25.0）, then were scanned by 120 kV tube voltage and ATCM under NI= 12.0. Standard deviation （SD） value was recorded. SNR and effective dose （ED） were calculated. The image quality was assessed by subjective scores. Results In the same NI value, tube voltage increased with the decreasing of water film＇s thickness when ATVS combined with ATCM scanning, and for the same phantom, tube voltage increased with the decreasing of NI value. When group A, B, C and D were scanned by ATVS combined with ATCM, the significantly negative correlation was found between ED, SNR and NI value （r=- 0.85, -0.87, -0.92, -0.96 and -0.87, -0.89, -0.91, -0.91, all P（0.05）, the significantly positive correlation was found between SD and NI value （r= 0. 97, 0.98, 0.98, 0.98, all P（0. 05）. When NI=12.0, subjective score of four phantoms were all ≥4. ED in group A, B and C scanned by ATVS combined with ATCM decreased by 20.74% （0.45 mSv/2.17 mSv）, 19.19% （0.52 mSv/2.71 mSv） and 7.38% （0.27 mSv/3.66 mSv） compared with those scanned by 120 kV tube voltage combined with ATCM and NI=12.0, respectively, and SD difference were not significant in superior mediastinum, heart and liver （all P〉0.05） ; SNR both had statistical significance in superior mediastinum, heart and liver of group A and B （both P〈 0.05） ; SNR was not significant in superior mediastinum, heart and liver of group C （P〉0.05） ; ED of group D increased by 31.05% （1.45 mSv/4.67 mSv）, and SNR increased by 29.88% （1.73/5.79）, 32.75% （1.67/5.10） and 22.90% （1.01/4.41） in superior mediastinum, heart and liver respectively. Conclusion High quality images can be obtained by AIVS combined with ATCM in thorax and abdomen CT scanning, and radiation dose can be significantly decreased.
出处
《中国医学影像技术》
CSCD
北大核心
2016年第9期1440-1444,共5页
Chinese Journal of Medical Imaging Technology
关键词
体层摄影术
X线计算机
自动管电压
自动管电流调制
辐射剂量
Tomography, X-ray computed
Automatic tube voltage selection
Automatic tube current modulation
Radiation dosage
