Impalpable Breast Cancer and Service Delivery During the COVID-19 Pandemic – the Role of Radiofrequency Tag localization

Background: Radiofrequency tags are used to localize breast lesions for surgery. During the Covid-19 pandemic, these offered the flexibility of inserting the Tags days or weeks before surgery. This made logistics of planning theatres lists easier, especially with most of the lists having been moved off site.Methods: In the 7 weeks following the first lockdown in the UK, we reviewed all planned admissions for breast surgery looking at the types of surgery offered, type of localization used and assessed which cases would not have been able to go ahead had radiofrequency tags not been available.Results: Out of 85 planned admission, 83 had surgery, 11 were for re-excision of margins and 72 for their first breast surgery excision (mastectomy or breast conservation). Out of the 54 that had breast conserving surgery, 40 needed localization, out of whom 27 had radiofrequency tags. Looking at theatre order list and location of surgery, 20 out of the 27 would not have had their surgery had radiofrequency tags not been available, which is 50% of the patients needing localization.Conclusion: Radiofrequency tags are new devices used for breast lesion localization that offer a much-needed flexibility especially as seen during the Covid-19 pandemic.

TagFi

Tag localization is crucial for many context-aware and automation applications in smart homes, retail stores, or warehouses. While custom localization technologies (e.g RFID) have the potential to support low-cost battery-free tag tracking, the cost and complexity of commissioning a space with beacons or readers has stifled adoption. In this paper, we explore how WiFi backscatter localization can be realized using the existing WiFi infrastructure already deployed for data applications. We present a new approach that leverages existing WiFi infrastructure to enable extremely low-power and accurate tag localization relative to a single scanning device. First, we adopt an ultra-low power tag design in which the tag blindly modulates ongoing WiFi packets using On-Off Keying (OOK). Then, we utilize the underlying physical properties of multipath propagation to detect the passive wireless reflection from the tag in the presence of rich multipath propagations. Finally, we localize the tag from a single receiver by forming a triangle between the tag reflection and the LoS path between the two WiFi transceivers. We implement TagFi using a customized backscatter tag and off-the-shelf WiFi chipsets. Our empirical results in a cluttered office building demonstrate that TagFi achieves a median localization accuracy of 0.2m up to 8 meters range.