Discipline of Medical Imaging Sciences, Faculty of Medicine and Health, The University of Sydney, NSW, Camperdown, Australia.
School of Physics, Australian National University, ACT, Canberra, Australia.
Br J Radiol. 2023 Oct;96(1150):20221189. doi: 10.1259/bjr.20221189. Epub 2023 Sep 8.
Propagation-based phase-contrast computed tomography (PB-CT) is a new imaging technique that exploits refractive and absorption properties of X-rays to enhance soft tissue contrast and improve image quality. This study compares image quality of PB-CT and absorption-based CT (AB-CT) for breast imaging while exploring X-ray energy and radiation dose.
Thirty-nine mastectomy samples were scanned at energy levels of 28-34keV using a flat panel detector at radiation dose levels of 4mGy and 2mGy. Image quality was assessed using signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), spatial resolution (res) and visibility (vis). Statistical analysis was performed to compare PB-CT images against their corresponding AB-CT images scanned at 32keV and 4mGy.
The PB-CT images at 4mGy, across nearly all energy levels, demonstrated superior image quality than AB-CT images at the same dose. At some energy levels, the 2mGy PB-CT images also showed better image quality in terms of CNR/Res and vis compared to the 4mGy AB-CT images. At both investigated doses, SNR and SNR/res were found to have a statistically significant difference across all energy levels. The difference in vis was statistically significant at some energy levels.
This study demonstrates superior image quality of PB-CT over AB-CT, with X-ray energy playing a crucial role in determining image quality parameters.
Our findings reveal that standard dose PB-CT outperforms standard dose AB-CT across all image quality metrics. Additionally, we demonstrate that low dose PB-CT can produce superior images compared to standard dose AB-CT in terms of CNR/Res and vis.
基于相位对比的 CT （PB-CT）是一种新的成像技术，利用 X 射线的折射和吸收特性来提高软组织对比度并改善图像质量。本研究比较了基于相位对比和基于吸收的 CT（AB-CT）在乳腺成像中的图像质量，同时探讨了 X 射线能量和辐射剂量的影响。
使用平板探测器在 28-34keV 的能量水平下对 39 个乳房切除标本进行扫描，辐射剂量分别为 4mGy 和 2mGy。使用信噪比（SNR）、对比噪声比（CNR）、空间分辨率（res）和可视性（vis）来评估图像质量。对 PB-CT 图像与在 32keV 和 4mGy 下扫描的相应 AB-CT 图像进行统计学分析。
在几乎所有能量水平下，4mGy 的 PB-CT 图像的质量均优于相同剂量的 AB-CT 图像。在某些能量水平下，2mGy 的 PB-CT 图像在 CNR/res 和 vis 方面也表现出优于 4mGy 的 AB-CT 图像的质量。在两种研究剂量下，SNR 和 SNR/res 均在所有能量水平上具有统计学显著差异。在某些能量水平下，vis 的差异具有统计学意义。
本研究表明，PB-CT 的图像质量优于 AB-CT，X 射线能量在确定图像质量参数方面起着关键作用。
我们的发现表明，标准剂量的 PB-CT 在所有图像质量指标上均优于标准剂量的 AB-CT。此外，我们还证明，在 CNR/res 和 vis 方面，低剂量 PB-CT 可以产生优于标准剂量 AB-CT 的图像。
