低管电压结合迭代重建腹部CT低剂量扫描的体模研究

发布时间：2018-04-16 03:33

  本文选题：低管电压 + 适应性统计迭代重建　； 参考：《放射学实践》2017年09期

【摘要】：目的:评价低管电压结合适应性统计迭代重建(ASIR)对腹部体模低剂量扫描图像质量的影响,探讨适合临床应用的腹部低剂量扫描方案。方法:采用100kVp、120kVp分别对体模进行重复扫描,应用自动管电流调节(ATCM)技术,100kVp扫描时预设噪声指数(NI)分别为11、12、13、14、15、16、17、18、19、20,每组图像均进行30%、50%、70%、90%ASIR重建。120kVp组为常规剂量组,扫描时预设NI为11,30%ASIR重建,测量不同扫描条件下肝脏、脊柱的CT值、客观噪声,并计算信噪比(SNR),记录不同扫描条件下的CT容积剂量指数(CTDIvol)。由两位高年资医师采用盲法对所有序列图像进行主观评价。结果:100kVp条件下,随着NI增大,CTDIvol明显下降;同一NI条件下随着ASIR比例增加,图像噪声减少,SNR增加;NI≥17时图像质量下降,无法满足临床诊断要求;NI=15、70%ASIR组图像噪声、SNR与120kVp常规组差异无统计学意义(P0.05),主观评分相当,但辐射剂量较常规组下降43.8%。NI=15、90%ASIR组及NI=16、90%ASIR组的图像噪声及信噪比优于常规组(P0.05),但图像质量主观评分下降。结论:低管电压结合ASIR可以在降低辐射剂量的同时保证图像质量满足临床诊断要求。辐射剂量明显降低时,需要增加ASIR在图像重建中的权重。
[Abstract]:Objective: to evaluate the effect of low tube voltage combined with adaptive statistical iterative reconstruction (ASIRR) on the quality of low dose scan images of abdominal phantom, and to explore a suitable low dose scan scheme for clinical use.Methods: the phantom was scanned repeatedly by 100kVp1 120kVp, and the default noise index (NII) of 100kVp was 111212131515161718181920 respectively. Each group was reconstructed with 30507090ASIR. 120kVp was used as the routine dose group, and the default NI was 1130ASIR at the time of scanning.The CT value and objective noise of liver and spine were measured under different scanning conditions. The SNR was calculated and CT volumetric dose index (CTDIvoll) was recorded under different scanning conditions.All sequence images were evaluated subjectively by two senior doctors using blind method.Results under the condition of 1: 100kVp, with the increase of NI, CTDIvol decreased obviously, and under the same NI condition, with the increase of ASIR ratio, the image noise decreased and the image quality decreased with the increase of NI 鈮，

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