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Koos Zevenhoven: The scientific world doesn't know this kind of unusual path very well

In a ‘Walk in My Shoes’ interview, Koos Zevenhoven shares a story of how he has led a research group during his PhD research and published dozens of papers on a novel MRI scanner technology and intelligent dynamics. Zevenhoven will be defending his own doctoral thesis on 20 November.
Koos Zevenhoven, photo by Oona Hilli
Photo: Oona Hilli

What was your path to Aalto and brain research?

When I graduated from Tapiola upper secondary school, I applied to study Engineering Physics and Mathematics at Aalto University. I was interested in physics and mathematics and had participated in international physics tournaments as captain and vice captain of the Finnish team. I also considered other options such as biology, medicine, and other engineering fields. However, engineering physics was harder to get into, which was tempting.

I first worked as a summer intern in the physics lab in the soft matter physics group. Then I found an interesting project at the Department of Neuroscience and Medical Engineering and started in Professor Risto Ilmoniemi's first EU project combining magnetoencephalography (MEG) and ultra-low-field magnetic resonance imaging (ULF MRI) in 2008.

During my master’s thesis, I visited UC Berkeley and worked on solutions for the imaging system there. After returning to Aalto, I continued to develop the theory while working on other hardware development projects. I have collaborated with the Berkeley group also later on.

I started my PhD research in 2011, and at that point we were building the first crude prototype of a combination brain scanner for measuring the location and dynamics of brain activity. Now, after various intermediate steps and side projects, we have finally got our first full-scale prototype to work. We still need further funding to make the scanner ready to be moved to the hospital, say in four years.

Risto Ilmoniemi on the left and Koos Zevenhoven in the middle, photo by Mikko Raskinen.
Prototype of a combination brain scanner for measuring the location and dynamics of brain activity. Risto Ilmoniemi on the left and Koos Zevenhoven in the middle. Photo: Mikko Raskinen

You will be defending your doctoral thesis on 20 November. What was the aim of the research?

The aim of my PhD research was broader than the combination brain scanner, for example different variations of MRI scanners. That part of the research aims at portability, low cost, light weight and even lower power consumption of the device.

The combination brain scanner, on the other hand, is expected to be useful for things like treatment planning of epilepsy. The developed technology can also be used for imaging other parts of the body and could be particularly useful for soft tissue diseases. The new technology could be more cost-effective, open, portable, and silent.

I have also developed a range of approaches in my PhD that others also outside Aalto can hopefully draw inspiration from. For progress, it has been important to solve crucial problems that are yet often circumvented for convenience. For many device components, there are no textbook solutions, and one has to develop something new – inventions are made in the process.

Intelligent dynamics is one of the themes of the PhD. What does it mean?

Dynamical pulse-waveform coupling has been the solution to surprisingly many problems. I have developed it for different applications and to tackle different issues. Although it has connections to existing solutions, this approach is my invention. In fact, we have patented it in multiple contexts.

When temporal shapes of magnetic pulses, for example, are equipped with the right features, hardware problems can be turned into software problems. It makes the implementations of the solutions lighter. Take, for example, a magnetic field pulse which is needed at some stage of the imaging sequence and which induces unwanted complex time-evolving eddy currents in structures. Based on theory and measurements, we can use a computer to generate another pulse, which is applied at the same time. Its shape is carefully designed to cancel out the harmful eddy currents.

For example, at UC Berkeley, part of an MRI machine caused eddy currents in surrounding aluminium walls. We applied another interestingly shaped pulse to cancel out the eddy current pattern. As a result, the complex eddy currents in the walls were eliminated at the end of the pulse and no longer interfered with the measurement.

Koos Zevenhoven sings in the choir Dominante.
Koos Zevenhoven sings in the Aalto University mixed choir Dominante. Photo: ESS.

You have been leading a research group for ten years now, which is quite exceptional for a PhD researcher. Was it hard to combine PhD research with group leadership?

I like leading the group and designing different sub-projects for its members. The members of my group are typically quite young, and the guidance has often been quite intensive.

There have also been PhD students in my group, and I haven’t been able to officially act as their advisor. Some of my students have finished their PhD before me.

Previously, when I was still a bachelor’s student, I was already the advisor for a master’s thesis. At the time, it felt perfectly natural. Maybe that's when I got used to the fact that I might one day be in the current situation.

So, often I've been more focused on other people's theses than my own, but at one point, it felt I should put my own thesis together. But then, there were setbacks in an EU project, and those were busy times and in fact quite intense.

Now I have eight publications in my dissertation, but there could have been even more. I’ve published some dozens of articles in total.

Would you do anything differently now?

One of course cannot predict everything, but after my master’s thesis I already had quite a bit of material, so it could have been possible to get the PhD out of the way quickly. But on the other hand, it suited me well to have a research group to lead at an early stage.

Koos Zevenhoven recently joined the band Sleeping at the Cinema.
Koos Zevenhoven performing with the band Astral Bazaar in 2017. He recently joined another band called Sleeping at the Cinema. Photo: Koos Zevenhoven.

What is it like to walk in your shoes?

On the one hand, the PhD research has been a large and broad project, but on the other hand, I've seen many dissertations along the way. It feels good to have soon finished it. The scientific world doesn't know this kind of unusual path very well. A PhD is required for many things.

I’ve been able to focus on a large number of things, because I've had people in my research group. But of course, it has also slowed down my PhD process. The size of the group has varied a lot, but at its largest it has been more than ten people. I still lead the group.

What are your plans after the doctoral defense?

I might take a little breather, and then we'll see what happens next. We are currently looking for funding for follow-up projects, and we'll have to see what the opportunities are. Sure, I’m interested in open job vacancies as well.

What do you do in your free time and why is it important to you?

I'm into music. I sing in the choir Dominante, and I recently joined the band Sleeping at the Cinema. I also enjoy electronics, swimming and multi-day hikes in the summer.

Further information:

Public defence in Engineering Physics, Biomedical Engineering, M.Sc. (Tech) Koos (Cornelis) Zevenhoven

Unconventional MRI scanner technology and intelligent dynamic

Interview by Tiina Aulanko-Jokirinne

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