Instrumentation

Utrecht PET/MRI

Pathophysiological guidance for small moving target volumes

Ambition

The Unity 1.5T MR-linac was clinically introduced to achieve stereotactic accuracy for tracking moving targets. We envision that combining the MR-linac with PET/MRI will enable PET data to guide stereotactic radiation therapy.

Vision

We envision the use of our PET/MRI system in a treatment pipeline with the MR-linac. The availability of MR images allows a precise transfer of the PET/MRI information to the MR-linac system for treatment guidance. In this way, information about the pathophysiology is available for real-time guidance on the MR-linac. The main purpose of the PET/MRI system in the pipeline is to localize and characterize pathophysiology of metastases by motion compensation. This will enable more precise radiation and thus decreasing toxicity and improving patient outcome.

Design

The design of our PET/MRI system facilitates our vision. The system offers 70 cm bore size and includes PET detectors mounted in the gap of a split gradient coil. The MRI hardware used in our wide bore PET/MRI and MR-linac systems is largely the same. Both systems have a 1.5T magnet and use identical hardware such as the gradient coil, the body coil and amplifiers. The similarities between the systems result in a nearly identical image quality and patient positioning. In turn, this allows for a spatially accurate transfer of pathophysiological information from the PET/MRI to the MR-linac. Both systems were designed explicitly to track the motion of the patient and to adapt the treatment accordingly.

Partners

The PET/MRI system was realized together with a group of partners: Uniklinik RWTH Aachen (DE), Philips Healthcare (NL), Futura Composites (NL), UMC Utrecht (NL), and Hyperion Hybrid Imaging Systems (NL).