Development and Evaluation of a Breast PET/MRI Insert Prototype for a Clinical Whole-Body PET/MRI Scanner

• Applicants: Professor Dr. Bernd Pichler; Professorin Dr. Magdalena Rafecas, Ph.D.; Professor Dr. Klaus Scheffler, Ph.D.
• Subject Area: Medical Physics, Biomedical Technology ; Radiology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 508064995

We aim to use the combination of the complementary detection sensitivities of Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI) to improve the diagnostic accuracy in breast cancer. The current whole-body clinical PET/MRI scanners were designed for a wide range of applications, not solely for breast imaging. This causes limitations in spatial resolution and detection sensitivity for imaging of the breast. Our goal is to overcome these limitations by the development of a breast-specific PET insert for a state-of-the-art clinical whole-body PET/MRI scanner. The concept proposed by our group further utilizes coincidences between the breast PET insert and the whole-body PET/MRI scanner. This enables a high precision for imaging of the axillary lymph nodes and metastasis outside of the breast which are essential for the classification of breast cancer and subsequent treatment guidance. For the development of the breast PET insert, we will utilize the expertise of our consortium in PET detector development, MR coil development, system design and integration, and image reconstruction. We developed prototype PET detectors that prove to have fulfilled the requirements of the breast PET insert with regards to a high spatial resolution and performance characteristics such as energy and time resolution. We further proved the MRI compatibility of these detectors, i.e. no mutual distortions while operated inside the 3T Biograph mMR (Siemens Healthineers, Erlangen, Germany). Further steps are a more compact design for integration into the MR coil and depth of interaction capability. Further, we have the expertise to develop an MR coil dedicated for breast imaging, which is capable to handle the close-by PET detectors of the breast PET insert and their corresponding shielding. We elaborated and compared initial designs of the breast PET insert based on Monte Carlo simulations. We will further extend the simulations to finalize the insert design and develop an image reconstruction that offers a combination of the insert and whole-body scanner. Therefore, our goal is to develop a unique fully integrated PET/RF-coil setup for high resolution, high sensitivity imaging of the female breast which slip-fits into a commercial clinical 3T PET/MR. This will allow PET coincidences between the two systems as well as total body and dedicated breast MRI. The mechanical construction and the software and hardware implementation will further allow an upgrade to a full four-ring system. However, this will be the next step and is not intended in this proposal to maintain the balance between risk and gain.

• DFG Programme: Research Grants