摘要
目的:研究CT扫描剂量、重建层厚、相同剂量下不同管电压对图像高对比度分辨力检测结果的影响,为规范CT设备质量控制检测和标准制修订提供数据支持。方法:在CT图像高对比度分辨力检测中,采用3种条件对Catphan600型影像质量模体的CTP528模块进行扫描:(1)保持CT图像的重建层厚不变,CT扫描剂量中在加权CT剂量指数(CTDIW)为70 mGy、60 mGy、50 mGy、40 mGy和30 mGy条件下分别对CTP528模块扫描;(2)保持扫描剂量为50 mGy不变,在层厚为10 mm、5 mm、1.25 mm和0.625 mm条件下分别对CTP528模块进行扫描;(3)保持重建层厚和扫描剂量不变,在管电压为100 kV、120 kV和140 kV条件下对CTP528模块进行扫描。比较分析3种测试条件下,对CTP528模块扫描的可分辨的最大线对组数。结果:CTDIW介于40 mGy和70 mGy之间时,均可清晰观察到图像中5 lp/cm的线对组,6 lp/cm线对组轻度粘连,7 lp/cm线对组明显粘连,8 lp/cm线对组均不能分辨。当CTDIW低至25 mGy时,5 lp/cm线对组开始出现轻度粘连;所有重建层厚的扫描图像均能清晰分辨5 lp/cm的线对组,但对于6 lp/cm的线对组,10 mm层厚图像中线对间粘连程度明显高于5 mm、1.25 mm和0.625 mm层厚;相同扫描剂量下100 kV、120 kV和140 kV条件下的模体影像可观察到的线对清晰度无明显差别。结论:在CT设备高对比度分辨力检测中CTDIW应设定为40~50 mGy,层厚应选择<10 mm;单纯管电压对图像高对比度分辨力的影响不大,管电压宜设置为>100 kV。
Objective: To study the effects of scanning dose, reconstructed slice thickness and different tube voltages under the same dose on the test results of the resolution with high contrast of computed tomography(CT) images, so as to provide data support for standardizing the test of quality control of CT equipment, and the formulation and revision of the relevant standards. Methods: In the test of resolution with high contrast of CT images, the CTP528 module of Catphan600 image quality phantom was scanned under 3 conditions:(1) The CTP528 module was respectively scanned under the different CT dose indexes(CTDIw) included 70 mGy, 60 mGy, 50 mGy, 40 mGy and 30 mGy in the doses of CT scan, which kept the reconstructed slice thickness of CT images.(2) The CTP528 module was respectively scanned under the different slice thicknesses included 10 mm, 5 mm, 1.25 mm and 0.625 mm when the scan dose was kept at 50 mGy.(3) The CTP528 module was respectively scanned under the different tube voltages included 100 kV, 120 kV and 140 kV when the reconstructed slice thickness and scan dose were kept. The maximum numbers of distinguishable line pairs of the scan under three kinds of test conditions on CTP528 module were compared and analyzed. Results: The 5 lp/cm line pair group in the images could be clearly observed, and 6 lp/cm line pair group appeared mild adhesion, and 7 lp/cm line pair group appeared obvious adhesion and 8 lp/cm line pair group could not be distinguished when CTDIwwas between 40 mGy and 70 mGy. The 5 lp/cm line pairs group began to show mild adhesion when the CTDIwwas as low as 25 mGy.All the scanned images with reconstructed slice thickness could clearly distinguish the 5 lp/cm line pair group, but the adhesion degree between different line pairs in the 10mm slice thickness image was significantly higher than that in the 5 mm, 1.25 mm and 0.625 mm slice thickness images for the 6lp/cm line pair group, respectively. There was no obvious difference in the clarity of observed line pairs of phantom images under 100
作者
赵锡鹏
顾枭成
陈飞
李玉文
张震
ZHAO Xi-peng;GU Xiao-cheng;CHEN Fei(National Center for Occupational Safety and Health,National Health Commission,Key Laboratory of Dust Hazard Engineering Protection,National Health Commission,Beijing 102308,China;不详)
出处
《中国医学装备》
2023年第1期12-16,共5页
China Medical Equipment
