Improved Cone Beam CT methods for intraoperative resection margin determination in breast cancer surgery

• Applicants: Dr. Jakob Neubauer; Dr. Martin Peter Pichotka
• Subject Area: Nuclear Medicine, Radiotherapy, Radiobiology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 534069778

The proposed project aims to develop, evaluate and optimize radiographic methods for the intraoperative analysis of surgical breast specimen. Such analyses serve to ensure the complete surgical removal of mammal carcinoma, which is a main predictor of patient outcome. An earlier study by the applicant has already shown that CBCT (Cone-Beram Computed Tomography) can deliver better determination of resection margins than the established methods of DM (Digital Mammography) and DTS (Digital Tomosynthesis). Beyond the scope of this previous study, the proposed project will include a comprehensive optimization of imaging performance, but also apply cutting-edge imaging hardware and novel imaging approaches with the goal to increase spatial resolution and image quality, and to reduce photon flux requirements. Additionally, using precision slice histology as the gold-standard will enable a very reliable quantitative comparison of the evaluated methods. • In addition to the clinical DM and extremity CBCT scanner used in a previous study, we will optimize and compare the performance of a state-of-the-art pre-clinical CT scanner, and a custom CBCT featuring photon-counting detectors (PCDs). Optimization of scanning protocols, X-ray spectra and volume reconstruction routines will be performed for all scanners separately, to realize their full potential in this application. The goal of this optimization is to maximize soft-tissue contrast and to improve the identification of microcalcifications, while minimizing reconstruction artifacts which could hinder the identification of pathological features. • We will investigate mechanically super-sampled PCD imaging as a tool to increase spatial resolution in mammographic imaging. Our preliminary results indicate a potential for substantial resolution enhancement and good dose performance of the employed super-sampling method. • We will evaluate a hybrid resolution imaging strategy, combining scans at different resolutions, to provide time and dose efficient 3D detection of microcalcifications in breast tissue. We expect a particularly high performance gain for dense breast tissue, where feature contrast of microcalcifications is reduced due to superimposition phenomena. • A reliable ground truth for comprehensive performance comparison of the investigated imaging approaches will be provided by precision slice histology of the surgical breast specimen included in this study. On this basis, the investigated methods can be quantitatively compared in terms of sensitivity, specificity and precision of resection margin determination.

• DFG Programme: Research Grants
• Co-Investigator: Dr. Marco Reisert