A method to assess image quality for Low-dose PET: analysis of SNR, CNR, bias and image noise.
A method to assess image quality for Low-dose PET: analysis of SNR, CNR, bias and image noise.
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DOI：
10.1186/s40644-016-0086-0
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发表时间：
2016-08-26
期刊：
影响因子：
--
通讯作者：
Townsend D
中科院分区：
文献类型：
--
作者：
Yan J;Schaefferkoette J;Conti M;Townsend D
降低注射剂量将对PET图像质量产生影响。在这篇文章中，我们的目的是研究这种影响的信号噪声比（SNR）在肝脏中，对比度噪声比（CNR）在病变，偏差和合奏图像噪声。我们在这里提出我们的方法和初步结果，结核病（TB）的情况下。16名接受18F-FDG PET/MR扫描的患者被选入本研究，扫描范围覆盖整个肺和部分肝脏。通过随机丢弃PET列表模式数据流中的事件来模拟减少的剂量，并且在每个模拟剂量下生成并重建10个实现。在从每个患者的原始完整统计数据重建的图像上描绘感兴趣体积（VOI）。使用四个阈值（SUVmax的20%、40%、60%和80%）来量化阈值在不同计数水平下对CNR的影响。计算每个VOI的图像指标。该实验使我们能够量化SNR和CNR的损失作为扫描中计数的函数，进而与注射剂量相关。研究了病变中平均和最大标准化摄取值（SUV平均值和SUV最大值）测量的重现性，作为10次实现的标准差。在5 × 106次扫描时，观察样本中肝脏的平均SNR约为3，CNR降低到全统计值的60%。随着计数数据的减少，病灶的CNR和肝脏的SNR降低。在计数水平为5 × 106之前，CNR在四个阈值上的变化不显著。在校正与受试者体重相关的因子后，发现肝脏中SNR的平方与检测到的计数具有非常好的线性关系。随着计数的减少，出现了一些定量偏倚。在5 × 106计数水平下，SUVmean和SUVmax的偏差和噪声分别达到10%和20%。为了保持偏倚和噪声均小于10%，SUV平均值和SUV最大值分别需要5 × 106和20 × 106个计数。对16例结核病患者数据的初步结果表明，扫描中5 × 106个计数足以产生SNR、CNR、偏差和噪声方面良好的图像。在未来，需要做更多的工作来验证所提出的方法与更大的人口和肺癌患者的数据。
Lowering injected dose will have an effect on PET image quality. In this article, we aim to investigate this effect in terms of signal-to-noise ratio (SNR) in the liver, contrast-to-noise ratio (CNR) in the lesion, bias and ensemble image noise. We present here our method and preliminary results using tuberculosis (TB) cases. Sixteen patients who underwent 18F-FDG PET/MR scans covering the whole lung and portion of the liver were selected for the study. Reduced doses were simulated by randomly discarding events in the PET list mode data stream, and ten realizations at each simulated dose were generated and reconstructed. The volumes of interest (VOI) were delineated on the image reconstructed from the original full statistics data for each patient. Four thresholds (20, 40, 60 and 80 % of SUVmax) were used to quantify the effect of the threshold on CNR at the different count level. Image metrics were calculated for each VOI. This experiment allowed us to quantify the loss of SNR and CNR as a function of the counts in the scan, in turn related to dose injected. Reproducibility of mean and maximum standardized uptake value (SUVmean and SUVmax) measurement in the lesions was studied as standard deviation across 10 realizations. At 5 × 106 counts in the scan, the average SNR in the liver in the observed samples is about 3, and the CNR is reduced to 60 % of the full statistics value. The CNR in the lesion and SNR in the liver decreased with reducing count data. The variation of CNR across the four thresholds does not significantly change until the count level of 5 × 106. After correcting the factor related to subject’s weight, the square of the SNR in the liver was found to have a very good linear relationship with detected counts. Some quantitative bias appears with count reduction. At the count level of 5 × 106, bias and noise in terms of SUVmean and SUVmax are up to 10 and 20 %, respectively. To keep both bias and noise less than 10 %, 5 × 106 counts and 20 × 106 counts were required for SUVmean and SUVmax, respectively. Initial results with the given data of 16 patients diagnosed as TB demonstrated that 5 × 106 counts in the scan could be sufficient to yield good images in terms of SNR, CNR, bias and noise. In the future, more work needs to be done to validate the proposed method with a larger population and lung cancer patient data.
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影响因子：
3.2
作者：
de Groot EH;Post N;Boellaard R;Wagenaar NR;Willemsen AT;van Dalen JA
通讯作者：
van Dalen JA
影响因子：
9.3
作者：
Oehmigen, Mark;Ziegler, Susanne;Quick, Harald H.
通讯作者：
Quick, Harald H.
影响因子：
39
作者：
Patz, Edward F., Jr.;Pinsky, Paul;Gatsonis, Constantine;Sicks, JoRean D.;Kramer, Barnett S.;Tammemaegi, Martin C.;Chiles, Caroline;Black, William C.;Aberle, Denise R.
通讯作者：
Aberle, Denise R.
DOI：
10.1007/s13246-011-0119-8
发表时间：
2012-03-01
影响因子：
--
作者：
Willowson, Kathy P.;Bailey, Elizabeth A.;Bailey, Dale L.
通讯作者：
Bailey, Dale L.
影响因子：
3.8
作者：
Doot, R. K.;Scheuermann, J. S.;Kinahan, P. E.
通讯作者：
Kinahan, P. E.