New tracer for inflammation behaves differently than expected

A new tracer designed to visualize inflammation in the body turns out to be less suitable than anticipated. That’s the outcome of research by PhD student Julia van der Bie. Her findings were published in Molecular Imaging and Biology — her first scientific publication.

A new tracer designed to visualize inflammation in the body turns out to be less suitable than anticipated. That’s the outcome of research by PhD student Julia van der Bie. Her findings were published in Molecular Imaging and Biology — her first scientific publication — shortly after another milestone: her first presentation at an international conference.

“Quite exciting, but above all really fun to do,” Julia says. “It’s a shame the tracer didn’t perform as we hoped, but it’s also valuable. Other researchers can build on this.”

You can read the complete article here.

A well-known challenge

Inflammation plays a key role in many diseases. To visualize it, researchers use radioactive substances — so-called tracers — in combination with PET scans.
“Basically, we’re using two substances to try and detect inflammation,” Julia explains. “One has been used in the clinic for longer, while the other is a newly developed variant. We wanted to see if the new one performs better — but it doesn’t.”

The widely used tracer [18F]DPA-714 has an important limitation: its effectiveness varies between individuals. “In some people it binds well, in others it doesn’t. That’s due to genetic variation — and ideally, you want something that works consistently.”

That’s why a new variant was developed: [18F]DPA-814, which was expected to overcome this issue and had previously shown promising results.

Looking at the whole body

In the study, Julia and her colleagues investigated whether this new tracer works in a COVID-19 model. Rhesus macaques infected with the virus were followed over the course of a year.

They were scanned multiple times, allowing researchers to track how inflammation developed and how both tracers behaved in the body — including in the lungs and the brain.
“With PET-CT, you can really look at the entire body,” Julia says. “That’s what makes this research so interesting. You’re not just seeing a small part, but the bigger picture.”

Understanding how things really work

Julia gradually found her way into this research field. After completing her applied sciences degree in biology and medical laboratory research, she realized she was missing theoretical depth. She moved on to university to study biomedical sciences.

“At applied sciences level, I spent a lot of time in the lab, but I wanted to understand what’s behind it. How does something actually work?”

During her studies, she discovered her interest in imaging.
“With a microscope, you look at a small area. With PET-CT, you can follow processes throughout the whole body. I found that fascinating right away.”

Ultimately, it’s about impact. “If we can better see what’s happening in the body, we can better understand how diseases develop.” She emphasizes that research progresses step by step:
“It’s not this one study on its own — but by building on findings like these, you gradually move closer to solutions.”

Building on results

The outcome was clear: the new tracer shows a different uptake pattern in the body compared to the existing one. In the lungs, [18F]DPA-814 was visible, but less suitable for reliably detecting specific sites of inflammation. Clear differences were also observed in the brain.

“The pattern of the new tracer is simply different,” Julia explains. “That means you can’t use it in the same way as the existing one.”

For now, the new tracer is not suitable as a replacement for [18F]DPA-714 — especially for studying inflammation in the lungs and brain. That may sound like a setback, but it isn’t.

“These kinds of results are actually very important. Now we know: this is not how it works. And that’s exactly what others can build on.”

The next step

The next step may lie with chemists, who could further refine the tracer.
“You start asking: why doesn’t it behave as expected? And how can we improve it?”

Tracers like these are used to visualize inflammation in a wide range of diseases, from Alzheimer’s and multiple sclerosis to infections and lung diseases.

For Julia, the motivation is clear: “If we can better see what’s happening in the body, we can ultimately better understand how diseases develop — and hopefully make a difference for patients