Department of Medical Imaging, Toronto General Hospital, and Department of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.
Phys Med Biol. 2010 Mar 7;55(5):1363-80. doi: 10.1088/0031-9155/55/5/007. Epub 2010 Feb 10.
Increased pixel noise and streak artifact reduce CT image quality and limit the potential for radiation dose reduction during CT of the thoracic inlet. We propose to quantify the pixel noise of mediastinal structures in the thoracic inlet, during low-dose (LDCT) and ultralow-dose (uLDCT) thoracic CT, and assess the utility of new software (quantum denoising system and BOOST3D) in addressing these limitations. Twelve patients had LDCT (120 kV, 25 mAs) and uLDCT (120 kV, 10 mAs) images reconstructed initially using standard mediastinal and lung filters followed by the quantum denoising system (QDS) to reduce pixel noise and BOOST3D (B3D) software to correct photon starvation noise as follows: group 1 no QDS, no B3D; group 2 B3D alone; group 3 QDS alone and group 4 both QDS and B3D. Nine regions of interest (ROIs) were replicated on mediastinal anatomy in the thoracic inlet, for each patient resulting in 3456 data points to calculate pixel noise and attenuation. QDS reduced pixel noise by 18.4% (lung images) and 15.8% (mediastinal images) at 25 mAs. B3D reduced pixel noise by approximately 8% in the posterior thorax and in combination there was a 35.5% reduction in effective radiation dose (E) for LDCT (1.63-1.05 mSv) in lung images and 32.2% (1.55-1.05 mSv) in mediastinal images. The same combination produced 20.7% reduction (0.53-0.42 mSv) in E for uLDCT, for lung images and 17.3% (0.51-0.42) for mediastinal images. This quantitative analysis of image quality confirms the utility of dedicated processing software in targeting image noise and streak artifact in thoracic LDCT and uLDCT images taken in the thoracic inlet. This processing software potentiates substantial reductions in radiation dose during thoracic LDCT and uLDCT.
像素噪声和条纹伪影增加会降低 CT 图像质量，并限制胸部入口 CT 降低辐射剂量的潜力。我们建议量化胸部入口纵隔结构的像素噪声，在低剂量 (LDCT) 和超低剂量 (uLDCT) 胸部 CT 期间，并评估新软件 (量子降噪系统和 BOOST3D) 在解决这些限制方面的效用。12 名患者进行了 LDCT（120 kV，25 mAs）和 uLDCT（120 kV，10 mAs）检查，最初使用标准纵隔和肺滤波器进行重建，然后使用量子降噪系统 (QDS) 降低像素噪声和 BOOST3D (B3D) 软件校正光子饥饿噪声，具体如下：组 1 不使用 QDS，不使用 B3D；组 2 单独使用 B3D；组 3 单独使用 QDS，组 4 同时使用 QDS 和 B3D。每个患者的胸部入口纵隔解剖结构中复制了 9 个感兴趣区域 (ROI)，共获得 3456 个数据点来计算像素噪声和衰减。QDS 将像素噪声降低了 18.4%（肺图像）和 15.8%（纵隔图像），在 25 mAs 时。B3D 在后胸部降低像素噪声约 8%，组合使用时，LDCT（肺图像为 1.63-1.05 mSv，纵隔图像为 1.55-1.05 mSv）的有效辐射剂量 (E) 降低了 35.5%，而在 LDCT 中，组合使用时，E 降低了 32.2%（肺图像为 1.55-1.05 mSv，纵隔图像为 1.55-1.05 mSv）。对于 uLDCT，同样的组合使 E 降低了 20.7%（肺图像为 0.53-0.42 mSv，纵隔图像为 0.51-0.42）。对图像质量的这种定量分析证实了专用处理软件在针对胸部入口处的胸部 LDCT 和 uLDCT 图像中的图像噪声和条纹伪影的效用。这种处理软件使胸部 LDCT 和 uLDCT 期间的辐射剂量大大降低成为可能。
