Limited Angle Image Reconstruction

描述（由申请人提供）：数字乳房断层合成（DBT）正被许多医疗设备制造商所追求，因为其有限的断层扫描能力直接解决了全视野数字乳房x线照相术（FFDM）的一个主要缺点。也就是说，由于投影成像的性质，由于重叠的正常组织结构有时与肿瘤相似，可能会出现假阳性，而由于肿瘤可能被正常组织掩盖，特别是在年轻女性的致密乳房中，可能会出现假阴性。许多关于DBT的研究已经完成或正在进行中，总的感觉是DBT确实有助于肿瘤检测，但在微钙化检测和表征方面可能不如FFDM，而微钙化检测和表征是可以间接指示恶性肿瘤的成像任务。本研究旨在优化DBT图像重建算法。例如，我们的初步结果已经表明，DBT中的微钙化成像受到图像重建算法的次优性的限制：我们的初步研究已经产生了微钙化信噪比的两倍增益。由于目前DBT中使用的许多迭代图像重建（IIR）算法基本上都是从核医学成像中借鉴而来，几乎没有修改，因此将IIR调整为DBT显然有很大的空间来提高图像质量。DBT设备已经进行了次优图像重建算法的临床试验，这一事实增加了拟议研究的紧迫性。本研究的目的是表明，通过调整IIR以适应DBT的应用，可以显著提高DBT的临床效用。本研究的目的是：(1)构建一个IIR框架，解决有限角度扫描和图像噪声和投影数量的固定剂量权衡问题。(2)基于设计优化的方法对投影截断具有鲁棒性。(3)开发DBT预测数据一致性检查和自动校正技术。(4)设计DBT图像的图像质量指标，进行算法优化。(5)与人类观察者一起评估算法性能。

DESCRIPTION (provided by applicant): Digital breast tomosynthesis (DBT) is being pursued by many medical device manufacturers, because its limited tomographic capability directly addresses a major short-coming of full-field digital mammography (FFDM). Namely, due to the nature of projection imaging, false positives can occur because overlapping normal tissue structures sometimes resemble tumors, and false negatives happen because tumors may be masked by normal tissue - particularly in dense breasts of young women. Many studies on DBT have been performed or ongoing and the general sense is that DBT does help for tumor detection, but it may perform worse than FFDM on microcalcification detection and characterization, which are imaging tasks that can indirectly indicate malignancy. The proposed research aims at optimizing image reconstruction algorithms for DBT. Our preliminary results indicate already, for example, that microcalcification imaging in DBT is limited by the sub-optimality of the image reconstruction algorithm: our initial investigations already yield a factor-of-two gain in microcalcification signal-to-noise ratio. As many of the current iterative image reconstruction (IIR) algorithms employed in DBT were essentially borrowed, with little modification, from nuclear medicine imaging there is clearly room for large gains in image quality for tailoring IIR to DBT. The fact that DBT devices are already undergoing clinical trials with sub-optimal image reconstruction algorithms increases the urgency of the proposed research. The goal of the research is to show that clinical utility of DBT can be enhanced significantly by tailoring IIR to application in DBT. The aims of the proposed research are: (1) Construct a framework for IIR addressing the limited angular scan and fixed-dose trade-off of image noise and number of projections. (2) Design optimization-based approaches robust against projection truncation. (3) Develop data consistency checks and automated correction techniques for DBT projections. (4) Design image quality metrics of DBT images for algorithm optimization. (5) Evaluate algorithm performance with human observers.