PhD Defense by Aslı Okur Kuru

Speaker: Aslı Okur Kuru Date: Wednesday, December 4th, 2019 Time: 12:00 Location: FMI-Building, Room 01.06.020

Challenges in Deployment of Advanced Radioguided Surgery Solutions

Abstract:

Radioguided surgery made it possible for the first time to functionally differentiate radioactively labeled target structures from the surroundings intraoperatively, which in most cases could not be previously achieved based only on the anatomical differences. The technique is based on the utilization of handheld radiation detectors to identify radiotracers injected into the patient, thus providing real-time guidance and feedback to the surgeon and opening a new era for minimally invasive surgery for the treatment or staging of numerous malignancies.

This thesis addresses several challenges associated with the deployment of new technologies in different clinical scenarios within the well-established radioguided surgery discipline, where the available systems are not necessarily optimized for the target clinical use case. It includes the analysis of the clinical workflow, definition of the supporting functions of the technology and its modification towards integrated applications on the concrete example of Freehand SPECT.

Freehand SPECT is a novel 3D nuclear functional imaging and navigation system suited for intraoperative usage, which was initially tailored to fulfill the surgical and technological requirements of the radioguided sentinel lymph node biopsy technique. Therefore, it needs alterations to be applicable for a new clinical use case having different requirements in terms of radiation detection, accuracy, performance, acquisition, visualization or real-time feedback. Furthermore, its overall success and its intraoperative acceptance is highly dependent on the particular human operator due to the freehand nature.

Retrospective analysis of automatic logging provided by Freehand SPECT system provides a basis for pinpointing the challenges associated with its utilization inside the operating room and allows us to learn from experience within the initial clinical use case. This enables not only the identification of potential usage problems, but also the detection of surgical phase transitions as well as usage characteristics for different users or user groups.

Building on top of this, we explore two new possible clinical use cases for Freehand SPECT. First, we propose the adaptation of Freehand SPECT imaging for recurring head and neck squamous cell carcinoma patients by the integration of a high energy gamma probe instead of the conventional (low energy) gamma probe due to the utilization of a positron emitting radiotracer. Secondly, we propose the first fully 3D Freehand SPECT - ultrasound fusion with the clinical motivation of non-surgical core needle biopsies of axillary sentinel lymph nodes for breast cancer.

Results of our experiments and evaluations demonstrate both the capabilities as well as the limitations of the proposed methods, which can be considered as initial steps towards advanced radioguided interventions. Especially the fusion of Freehand SPECT and ultrasound has the potential to revolutionize the nodal staging of early stage breast cancer by providing a less invasive alternative to the state-of-the-art radioguided sentinel lymph node biopsy technique.