Dose Reduction and Performance Enhancement During DBT Screening

描述(申请人提供)：数字乳房断层合成(DBT)能够从从不同角度获得的一系列2-D投影中重建多个水平的乳房组织。它的主要优点是，它生成的体积数据集允许解决投影乳房X光片中经常出现的组织叠加歧义。目前正在研究将DBT用作主要筛查方式，但与辐射暴露和检测性能有关的问题仍然存在。在之前的回溯性观察者表现中，我们发现DBT与全场数字乳房摄影(FFDM)相结合，在保持灵敏度的同时，召回率降低了30%，但联合检查使辐射暴露增加了一倍。当DBT单独与FFDM相比时，减少的幅度仅为10%。召回率降低30%就足以证明将DBT纳入筛查方案是合理的，但如果它需要比FFDM双倍的辐射暴露就不合理了。这项建议的目的是确定是否可以通过使用合成的FFDM(由适当重建的DBT数据的高分辨率(70-5m)投影组成)来替代直接获得的FFDM来实现30%的减少，而不需要单独获得FFDM和DBT研究。为了测试这一点，我们将开发用于从DBT数据中导出合成FFDM的算法，然后执行观察者性能研究，该研究测量1)单独的FFDM，然后是FFDM与传统DBT的组合，以及2)传统的DBT，然后是DBT与合成的FFDM的组合的性能。模式1以前已被证明可提供上述性能提升，但需要的辐射剂量是模式2的两倍。这两个研究臂使我们能够单独测量FFDM、FFDM+DBT、单独DBT和DBT+合成FFDM的性能。性能研究将让8名放射科医生在两种模式下阅读100例病例，并报告BIRADS评分和ROC类型评分。每个病例将包括在我们的HOGIC DBT系统上的单个程序中获得的一个FFDM和一个DBT。这项工作意义重大，因为如果我们的目标是用从DBT数据得出的投影取代FFDM采集，那么就有可能在不增加辐射暴露的情况下将召回率降低30%。 公共卫生相关性：乳房断层扫描是最近推出的一种成像方式，如果在筛查环境中与乳房X光检查结合使用，可以显著降低召回率，同时保持筛查灵敏度。然而，这项联合检查比单独进行乳房X光检查所需的辐射暴露增加了一倍。该项目测试了将DBT整合到乳腺癌筛查环境中的各种策略，这些策略可能能够在不增加辐射暴露的情况下保持性能改进。这可能会大大减少因假阳性筛查结果而不必要地召回的女性数量。

DESCRIPTION (provided by applicant): Digital Breast Tomosynthesis (DBT) enables 3-D reconstruction of multiple levels of breast tissue from a series of 2-D projections acquired at different angles. Its main advantage is that it generates a volumetric dataset that allows resolution of tissue superposition ambiguities that are often present in projection mammograms. DBT is currently being investigated for use as a primary screening modality but issues related to radiation exposure and detection performance remain. In a previous retrospective observer performance we found that DBT in combination with Full Field Digital Mammography (FFDM) reduced recall rates by 30% while maintaining sensitivity, compared to FFDM alone, but the combined examination doubled radiation exposure. When DBT alone was compared to FFDM the reduction was only 10%. A 30% reduction in recall rates would be sufficient to justify incorporating DBT into screening protocols, but not if it requires doubling the radiation exposure over that of FFDM. The intent of this proposal is to determine whether the 30% reduction can be achieved without acquiring separate FFDM and DBT studies by using a synthetic FFDM, comprised of a high-resolution (70-5m) projection of appropriately reconstructed DBT data, as a substitute for the directly acquired FFDM. To test this we will develop algorithms for deriving the synthetic FFDM from the DBT data and then perform an observer performance study that measures performance of 1) FFDM alone followed by FFDM combined with traditional DBT, and 2) traditional DBT alone followed by DBT combined with the synthetic FFDM. Mode 1 has previously been shown to provide the performance gains discussed above, but requires twice the radiation dose of mode 2. The two study arms enable us to measure performance of FFDM alone, FFDM + DBT, DBT alone, and DBT + synthetic FFDM. The performance study will have 8 radiologists read 100 cases in both modes and report BIRADS scores and ROC-type scores. Each case will include an FFDM and a DBT acquired in a single procedure on our Hologic DBT system. This work will be significant because, if our goal of replacing the FFDM acquisition with a projection derived from the DBT data is successful, then it will be possible to achieve the 30% reduction in recall rates without the increased radiation exposure. PUBLIC HEALTH RELEVANCE: Breast tomosynthesis is a recently introduced imaging modality that can significantly reduce recall rates, while maintaining screening sensitivity, if used in conjunction with mammography in a screening environment. However, this combined exam doubles the radiation exposure over that required for mammography alone. This project tests various strategies for incorporating DBT into breast cancer screening environments that may be able to retain the performance improvements without the increase in radiation exposure. This could greatly reduce the number of women unnecessarily recalled because of a false positive screening result.