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

我们的目的是利用正电子发射断层扫描（PET）和磁共振成像（MRI）的互补检测灵敏度的结合来提高乳腺癌的诊断准确性。目前的全身临床PET/MRI扫描仪设计用于广泛的应用，而不仅仅是用于乳房成像。这就限制了乳房成像的空间分辨率和检测灵敏度。我们的目标是通过为最先进的临床全身PET/MRI扫描仪开发乳房特异性PET插入物来克服这些限制。我们小组提出的概念进一步利用了乳房PET插入物和全身PET/MRI扫描仪之间的巧合。这使得腋窝淋巴结和乳腺外转移的成像精度高，这对乳腺癌的分类和后续治疗指导至关重要。对于乳房PET植入物的开发，我们将利用我们联盟在PET检测器开发，MR线圈开发，系统设计和集成以及图像重建方面的专业知识。我们开发的原型PET探测器证明已经满足了乳房PET插入物在高空间分辨率和性能特征（如能量和时间分辨率）方面的要求。我们进一步证明了这些检测器的MRI兼容性，即在3T Biograph mMR内操作时没有相互扭曲（Siemens Healthineers, Erlangen, Germany）。进一步的步骤是一个更紧凑的设计集成到磁共振线圈和深度的互动能力。此外，我们还拥有专门开发用于乳房成像的MR线圈的专业知识，该线圈能够处理乳房PET插入物的近距离PET探测器及其相应的屏蔽。在蒙特卡罗模拟的基础上，详细阐述并比较了乳房PET植入物的初步设计。我们将进一步扩展模拟，最终确定植入物的设计，并开发一种结合植入物和全身扫描仪的图像重建方法。因此，我们的目标是开发一种独特的完全集成的PET/ rf线圈装置，用于高分辨率，高灵敏度的女性乳房成像，可用于商业临床3T PET/MR。这将允许PET在两个系统之间以及全身和专用乳房MRI之间的一致性。机械结构和软件和硬件的实施将进一步升级到一个完整的四环系统。然而，这将是下一步，在本建议中并不打算保持风险与收益之间的平衡。

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.