摘要
目的研究PET/CT中CT自动管电流模式图像质量与受检者有效剂量(ED)的关系,探讨最优釆集方案。方法使用美国GE Discovery ST-16型和Discovery Elite型PET/CT设备对仿真人体模型进行扫描,CT采集条件相同:管电压120kV,螺距1.375,转速0.8 s,噪声指数8~30,间隔为2,自动管电流低限30 mA,高限200-350 mA,间隔50 mA。计算腹部主要器官噪声、信噪比(SNR)及优良指数(FOM),分析图像质量与ED间的关系。组间比较采用两样本t检验。结果各器官图像噪声随ED增加而降低,但ST-16型ED增至15 mSv、Elite型增至12 mSv后,图像噪声降低幅度减小,变化趋势平缓。各器官图像SNR随ED增加而升高;肝脏FOM随ED增加而降低,其他器官FOM随ED增加变化不明显。相同ED(5~20 mSv)时,Elite型扫描图像指标均优于ST-16型,但差异无统计学意义(t值:0.133-4.701,均P>0.05):ED为5 mSv时,ST-16型肝脏图像噪声较Elite型高岀12.0%(28.9与25.8), Elite型肝脏图像SNR及FOM较ST-16型分别高出13.9%(4.1与3.6)及66.7%(0.50与0.30)。结论2种机型所致ED在5-20 mSv间,在一定范围内增加ED,图像质量随之提高。
Objective To investigate the relationship between image quality of PET/CT in automatic tube current modulation and effective dose(ED) of patients and to detennine 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. Resuits 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 mSv, 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 mSv, the image quality is improved along with the ED increasing in a certain range.
作者
吴一田
耿建华
杜召猛
毕高畅
齐雍鹤
张朝坤
郑容
吴宁
Wu Yitian;Geng Jianhua;Du Zhaomeng;Bi Gaochang;Qi Yonghe;Zhang Chaokun;Zheng Rong;Wu Ning(Department of PET/CT Center, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China;Department of Nuclear Medicine, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China)
出处
《中华核医学与分子影像杂志》
CAS
北大核心
2019年第3期153-156,共4页
Chinese Journal of Nuclear Medicine and Molecular Imaging
基金
国际科技合作项目(2009DFA32960)
中国癌症基金会北京希望马拉松专项基金(LC2016A02).
