Relationship between image quality of PET/CT in automatic tube current modulation and effective dose
10.3760/cma.j.issn.2095-2848.2019.03.007
- VernacularTitle:PET/CT中CT自动管电流模式的图像质量与受检者有效剂量关系的研究
- Author:
Yitian WU
1
,
2
;
Jianhua GENG
;
Zhaomeng DU
;
Gaochang BI
;
Yonghe QI
;
Chaokun ZHANG
;
Rong ZHENG
;
Ning WU
Author Information
1. 国家癌症中心、中国医学科学院北京协和医学院肿瘤医院PET/CT中心 100021
2. 国家癌症中心、中国医学科学院北京协和医学院肿瘤医院核医学科 100021
- Keywords:
Photon-emission tomography;
Tomography,X-ray computed;
Radiation dosage;
Abdomen;
Manikins
- From:
Chinese Journal of Nuclear Medicine and Molecular Imaging
2019;39(3):153-156
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the relationship between image quality of PET/CT in automatic tube current modulation and effective dose(ED) of patients and to determine the optimal acquisition scheme.Methods Scanning was performed on anthropomorphic phantom RS-550 using GE Discovery ST-16 or Discovery Elite PET/CT.The same CT acquisition conditions was used:tube voltage 120 kV,pitch 1.375,rotation speed 0.8 s,noise index ranged from 8 to 30,interval 2,automatic tube current low limit 30 mA,high limit ranged from 200 to 350 mA,interval 50 mA.The images were analyzed,and the noise,signal to noise ratio (SNR) and figure of merit (FOM) of main organs in the abdomen were calculated.The relationship between image quality and ED was analyzed.Two-sample t test was used for data analysis.Results The noise of each organ decreased significantly along with the increase of ED until the ED of ST-16 increased to 15 mSv or Elite increased to 12 mSv,then the image noise decreased gently.SNR of each organ image increased along with the increase of ED.The FOM of liver decreased along with the increase of ED,while the FOM of other organs did not change significantly with ED.All image indicators of Elite PET/CT were better than ST-16 PET/CT at the same ED (5-20 mSv),though there was no significant difference (t:0.133-4.701,all P＞0.05).When ED was 5 mSy,the noise of liver with ST-16 was 12.0％ (28.9 vs 25.8)higher than that with Elite,and the SNR and FOM of liver with Elite was 13.9％ (4.1 vs 3.6) and 66.7％ (0.50 vs 0.30) higher than that with ST-16,respectively.Conclusion When the ED caused by the 2 PET/CT systems was between 5-20 mSy,the image quality is improved along with the ED increasing in a certain range.
