Microbeam Therapy for Clinical Use
The Brain, in One Moment
Perspectives – BrainPET-7T-Tomograf
Anyone who wants to understand the brain eventually has to answer three questions: What does it look like? How do its nerve cells communicate? And what chemistry is at work beneath the surface? PET/MRI systems are meant to show all three at once. Until now, however, they have been held back by limited resolution and sensitivity. Researchers in Jülich have now pushed the technology further, opening up new possibilities for neuroscience.
June 2026
A precise combined image: simultaneous scans of a head phantom show biological function (PET, top) and anatomical structure (MRI, bottom), acquired at the same time (middle row).
A Map of the Human Brain
To map the human brain, doctors send patients into the tube of an MRI scanner. Inside, powerful electromagnetic fields make imaging possible, but they also interfere with conventional electronics. Most hospitals work with field strengths of 1.5 or 3 tesla. In Jülich, researchers use 7 tesla. This ultra-high-field MRI shows the brain’s folds, grooves and networks with extraordinary sharpness, down to fine anatomical detail. MRI has become one of medicine’s and neuroscience’s most important tools. And yet, even that is often not enough.
A brain can look perfectly normal and still be ill. In severe depression, for instance, conventional MRI scans often show nothing at all. In Alzheimer’s disease, damage begins long before the structure of the brain visibly changes. In Parkinson’s disease and many psychiatric disorders, the decisive processes often do not play out in anatomy, but in the brain’s signalling pathways and metabolism. To see them, researchers need a second perspective: biochemistry.
Positron emission tomography, or PET, reveals what MRI cannot. Patients receive a weakly radioactive tracer that shows where the brain is consuming energy, which messenger systems are active and how biochemical processes change. Combined, PET and MRI bring structure, function and metabolism together in one image of the brain.
The difficulty is timing. In conventional systems, doctors often perform PET and MRI scans separately and overlay the images afterwards by computer. But the brain is changing all the time. The images may fit digitally; physiologically, they often no longer capture the same instant. Researchers, too, have had to work with that compromise when trying to understand what is happening in the brain.
Faster, Sharper, Simultaneous
Dr. Christoph Lerche and his team want to end that compromise. Lerche leads the PET group at the Institute of Neurosciences and Medicine – Medical Imaging Physics. Together with researchers from other parts of Forschungszentrum Jülich, including the MR group led by Dr. Jörg Felder, and with partners at RWTH Aachen University, they have developed BrainPET-7T. With a single scan, the system produces high-resolution images of structure, function and metabolism from the very same state of the brain.
Prof. Jon Shah, Director of INM-4, explains why this matters using psychiatric disorders as an example: “At the moment, doctors often have to wait weeks or months to know whether an antidepressant is working. With BrainPET-7T, they could see directly what a drug is actually doing in the brain and how the affected region responds at that same moment.” In the long term, Shah says, such insights could help researchers better understand neurological and psychiatric illness, including Alzheimer’s and Parkinson’s disease.
Until now, looking into the living brain has been a little like looking through steamed-up glass. You can make out the outlines, but the details that matter remain blurred. The new system cuts through much of that haze. Where earlier devices work with around 500,000 image elements, BrainPET-7T brings three-dimensional images with 3.5 million voxels to the screen – seven times as much information. The key is sensitivity: its detectors capture the tracer’s gamma rays so efficiently that image noise drops sharply. That allows researchers to observe molecular processes in the brain far more precisely.
„Despite the smaller budget, our system leads internationally in key technical benchmarks such as resolution and sensitivity.“
— Dr. Christoph Lerche
Keeping Two Technologies Apart
The Jülich tomograph consists of a custom-developed PET scanner integrated into a 7-tesla MRI system from Siemens Healthineers – the project’s biggest technical challenge. Running both systems at the same time is extremely difficult. The MRI’s strong magnetic field can disrupt the PET scanner’s electronics, while the PET sensors can, in turn, affect the MRI.
The researchers solved the problem with an insert that can be moved into and out of the MRI scanner. Special shielding prevents the two systems from interfering with each other. At the same time, the team designed the head coil needed for high-resolution MRI so that it remains as transparent as possible to the PET detectors. The MRI system itself was left unchanged, preserving its clinical certification.
A System Built to Compete Internationally
The road to this innovation was anything but straight. The BrainPET-7T project began back in 2016. Years passed before all partners were on board, contracts were in place and the technical infrastructure had been built. The result is now one of the world’s most advanced platforms for simultaneous ultra-high-field PET/MRI research.
Financially, too, the project is unusual. Other sites are working on similar systems, often with much larger budgets. In the United States, universities such as Harvard and Yale invest sums in the tens of millions in comparable technologies. The Jülich team had about four million euros. “Despite the smaller budget, our system leads internationally in key technical benchmarks such as resolution and sensitivity,” Lerche says.
„The hurdles for a new medical device are high"
— Prof. Jon Shah
Even so, BrainPET-7T is still at the beginning. “The hurdles for a new medical device are high,” Shah explains. Anyone who wants to use such a system in humans must prove, without gaps, that it is safe. The team is currently preparing its first studies and tests with volunteers.
“If everything works as we hope, BrainPET-7T will take us into a new era of multimodal imaging,” Shah says. In research, it could make it possible to study the complex interplay between the brain, its metabolism and other organs, such as the gut. In the longer term, the technology could also become relevant for clinical use – as a high-end extension for the growing number of 7-tesla MRI centres. “That is why we designed our system so that clinics do not put existing MRI approvals at risk,” Lerche adds.
Brain Imaging on a New Level: The BrainPET-7T
Univ.-Prof. Dr. Dr. h.c. N. Jon Shah
Director of the Institute of Neurosciences and Medicine (INM-4) and is driving the development of next-generation hybrid imaging technologies
Go to the Profile of Prof. Dr. Dr. h.c. N. Jon Shah
Dr. Christoph Lerche
leads the research group behind the BrainPET-7T tomograph
More on the institute (INM-4)
Dr. Jörg Felder
leads the MR group at the Institute for neuroscience and medicine (INM-4) and develops innovative hardware components for high-field MRI systems.
More on the MR research group
Image Credits: Forschungszentrum Jülich
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Last Modified: 09.07.2026