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Kristoffer is a new MRC Group Leader. In this interview, Kristoffer tells us about his research in FLASH radiation and the benefits and challenges involved, gives an overview of his career path to becoming a Group Leader, and talks about life outside of work.

So, FLASH radiation?! Can you tell us what it’s all about and the main focus of your research? 

FLASH radiation is radiation delivered at an ultra-high dose rate. In conventional radiation therapy, the therapeutic dose is delivered in a few minutes per treatment. In FLASH, the dose is often delivered in a few hundredths of a second or even quicker. Preclinical studies have shown that normal healthy tissues are less adversely affected (up to 50%) by the radiation if it’s delivered with FLASH, while it seems to be no less effective in treating tumour tissues. We are mainly working on trying to explain the mechanisms behind this highly beneficial radiobiological effect, which you get when the dose rate and speed of delivery is increased from conventional irradiation to FLASH. We are also investigating how this new radiotherapy technique should be introduced in an optimal way in our cancer treatment clinics.

Why does this research matter?

Another effect of the rapid delivery of FLASH irradiation is that there is no time for the tumour to move during the treatment. This means that we could potentially remove the treatment margins which are usually added to take the tumour motion into account, thereby targeting less of the healthy tissue resulting in reduced adverse effects.

Also, quick treatments are more comfortable for the patients receiving them, as they do not have to be fixed in the treatment position for a lengthy period of time. This logistical benefit together with the biological benefit mentioned above means that FLASH will result in reduced adverse effects for the patients receiving radiotherapy.

With FLASH, we could potentially cure tumours we currently cannot cure, as it allows for a substantial increase in the radiation dose. Hence, FLASH has the potential to revolutionise the way radiotherapy is delivered, if introduced in our clinics in an optimal way.

Are there any particular challenges?

FLASH is currently almost exclusively available for electron and proton treatments, with X-ray/photon treatment only made possible at large experimental facilities such as the European Synchrotron facility in Grenoble. Treatment with electrons are generally limited to preclinical studies or only treating superficial tumours in clinical studies. Treatment with protons can reach deep-seated tumours but require large and expensive facilities to generate the treatment beams.

For FLASH to really make an impact in the clinic, technological advancements are needed that would allow FLASH to be delivered with X-rays/photons, generated using medical equipment (e.g. linear accelerators) of reasonable size, i.e. that can fit in a normal radiotherapy bunker. We are also working on addressing this challenge.      

How did you get to where you are today?

I studied to become a Medical Physicist in Lund, Sweden. Following my M.Sc. in Medical Radiation Physics, I started working as a clinical Medical Physicist in the radiotherapy department in Lund. After 7.5 months and following the advice of by boss Tommy Knöös, I quit to pursue a Ph.D. in Medical Radiation Physics. The opponent chosen for my Ph.D. defence was a Medical Physicist called Raphaël Moeckli, from Lausanne, Switzerland. At the dinner following my successful defence, Raphaël told me that they were looking for a post-doc to work on the dosimetry for their new exciting and secret project. I was intrigued, went down to Switzerland for a job interview and was offered the position.

Of course, the project was on FLASH radiation working with the radiobiology team of Marie-Catherine Vozenin. I stayed for three intense and interesting years in Lausanne, after which I returned to Lund to work as clinical Medical Physicist and to start up my own research group on FLASH radiotherapy.

When I discovered the Department would be hiring a Group Leader to run a research group focusing on FLASH radiation, this was an opportunity I could not miss and so, after a successful interview, I ended up here in Oxford.    

What are the bigger questions in your field? How do you see your field developing in the next five-ten years?

Currently, the biggest question is why do we get a beneficial FLASH effect? Another big question is if the effect can be further enhanced, perhaps in combination with a drug? A third big question is how to make this technique available to our cancer patients in the clinic? There is still a lot of preclinical studies and technological developments needed before we can answer these questions.

In the next five-ten years, I expect that FLASH will become available in the clinic, though probably still as a specialised treatment. It will probably be a few more years before it will be the most common way of delivering our cancer treatments.  

What’s life like outside of work? What do you do to relax?

I live with my girlfriend, dog and cat in a house in Kennington, south of Oxford. In Sweden, I used to play football and enjoy riding my motorbike. I hope to start enjoying that here as well.