Navigating towards the unseen margins of non-palpable breast cancer

Within this thesis we aimed to improve the current clinical workflow regarding planning, intra-operative guidance and evaluation of surgical outcome of patients with non-palpable breast cancer undergoing breast conserving surgery (BCS). In Part 1 we focused on improving localization and visualization of the tumor. The use of radioactive seed localization (RSL) as a tumor localization technique still provides an oversimplification of large non-palpable tumors, simply because the surgeon has no knowledge about the specific tumor volume during the operation. A first step forward could be made by acquiring breast MRI in supine position, visualizing the tumor similar to BCS. Although our presented scan protocol is not ready to be directly implemented into clinical practice, our first results are promising and encourage further research on using supine breast MRI for planning of BCS. This scan is preferably used as input for our presented surgical navigation system based on real-time tumor tracking in Part 2, providing intra-operative visual guidance towards tumor borders. Especially the resection of extensive tumors in phantoms improved with navigation guidance in comparison to standard iodine-seed guidance. Furthermore all participating surgeons were enthusiastic about the presented surgical navigation system. Part 3 aimed to improve current evaluation of BCS by analyzing the diagnostic accuracy of microCT (µCT) for analysis of the surgical resection margins within breast excision specimen. Micro-CT imaging could provide fast feedback about surgical resection margins during BCS but at this point suffers from a too low diagnostic accuracy in order to be directly implemented into clinical practice.