Reduction of scatter in breast CT yields improved microcalcification visibility
Reduction of scatter in breast CT yields improved microcalcification visibility
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DOI：
10.1088/1361-6560/abae07
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发表时间：
2020-12-07
影响因子：
3.5
通讯作者：
Ghazi, Peymon
中科院分区：
文献类型：
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作者：
Ghazi, Peymon
微钙化（提示放射科医生早期癌症的小钙沉积）的可见性不足是目前专用乳腺计算机断层扫描（bCT）设计的主要限制。这种限制以前被归因于组成成分、空间分辨率和使用剂量。散射辐射被认为是一种低频影响，可以在后处理中进行补偿。然而，我们假设，散射辐射的采集对临床相关特征的不利影响比以前所理解的要大得多。至关重要的是，散射的采集导致微钙化的可见性降低。这一假设进行了调查，并通过数学推导和模拟研究的支持。我们进行了一系列的比较研究，其中四个bCT系统进行了模拟等剂量和等分辨率条件下，表征微钙化对比度的累积散射的依赖性。包括在模拟系统是一种新的bCT设计窄束bCT（NB-bCT）-捕捉几乎为零的散射。我们发现，目前的bCT系统遭受显着水平的散射。如理论上所验证的，根据系统和微钙化的大小，由于散射，25%至70%以上的对比度分辨率损失。然而，NB-bCT的结果提供了证据，证明通过去除投影中的散射积聚，bCT图像中微钙化的对比度得以保留，而无论其在乳房中的大小或位置如何。
The inadequate visibility of microcalcifications-small calcium deposits that cue radiologists to early stages of cancer-is a major limitation in current designs of dedicated breast computed tomography (bCT). This limitation has previously been attributed to the constituent components, spatial resolution, and utilized dose. Scattered radiation has been considered an occurrence with low-frequency impacts that can be compensated for in post-processing. We hypothesized, however, that the acquisition of scattered radiation has a far more detrimental impact on clinically relevant features than has previously been understood. Critically, acquisition of scatter leads to the reduced visibility of microcalcifications. This hypothesis was investigated and supported via mathematical derivations and simulation studies. We conducted a series of comparative studies in which four bCT systems were simulated under iso-dose and iso-resolution conditions, characterizing the dependencies of microcalcification contrast on accumulated scatter. Included among the simulated systems is a novel bCT design-narrow beam bCT (NB-bCT)-that captures nearly zero scatter. We find that current bCT systems suffer from significant levels of scatter. As validated in theory, depending on the system and size of microcalcifications, between 25% and over 70% of contrast resolution is lost due to scatter. The results in NB-bCT, however, provide evidence that by removing scatter build-up in projections, the contrast of microcalcifications in a bCT image is preserved, regardless of their size or location in the breast.