Katrinus Keijnemans is a PhD student at the University Medical Center Utrecht in the Netherlands who received an EACR Travel Fellowship to visit and work at the Medical College of Wisconsin, Milwaukee in the US between July and October 2024.
The EACR, with support from Worldwide Cancer Research, provides Travel Fellowships of up to €3,500 to enable early-career cancer researchers to gain new skills through a short-term visit to a lab or research group in another country.
You can read about other Travel Fellows and their experiences here.
Name: Katrinus Keijnemans
Job title: PhD student
Home institute: University Medical Center Utrecht in the Netherlands
Host institute: Medical College of Wisconsin, Milwaukee, US
Dates of visit: 29 July – 23 October 2024
Other funding organisations who supported your trip: UMC Utrecht, ELEKTA AB, Stichting de Drie Lichten
Research: To deliver radiation dose at the location of the tumour, the tumour position has to be known. Tumours in the thoracic region move due to breathing. A 4D-CT is a technique that images the 3D anatomy in different respiratory phases. In the last two decades, MR imaging has been introduced in the field of radiotherapy. My research focusses on quantifying the breathing motion using 4D-MRI to more accurately account for motion. If we can monitor the breathing-induced motion during the treatment, we can reduce the uncertainty and therewith the amount of radiation delivered to healthy tissue around the tumor location.
Why did you choose the host lab?
There were two reasons why I chose this lab: 1) The host lab was chosen because they are pioneers in using 4D-MRI (3D anatomy + breathing phases) for patients. A 4D-MRI can be derived using certain acquisition and reconstruction software, and represents the average breathing cycle. In my home institute, I have been working on a different approach to obtain a 4D-MRI compared to the host lab. In contrast to MCW, we at UMC Utrecht do not have a clinical implementation of acquiring/using a 4D-MRI yet. This visit gave me the opportunity to shadow and learn about the clinical practice of 4D-MRI.
2) Furthermore, there has been a long withstanding collaboration between my PhD supervisor and the leader of the host lab. This has led to a research collaboration between me and the leader of this lab for a publication to compare different 4D-MRI techniques that show promising results for their use in radiotherapy. This visit gave me the opportunity to share our latest research outcomes with the host lab as well.
Can you summarise the research you did or what you learned on your visit?
One of my main activities was setting up the software to give breathing instructions during CT and MRI acquisitions. The idea behind these instructions is that if patients breathe more regularly, it will result in better quality images and also improved treatment as a result of more consistent and predictable movement of the anatomy and tumour. In the host lab, a clever setup was used with a Raspberry Pi and augmented reality glasses to display instructions to the subject. I was unfamiliar with providing visual feedback to the subject in this way prior to my visit to the host lab.
Another main activity was the development of software to automatically derive the region of interest around the tumour location that has to be irradiated. This technique results in smaller volumes being irradiated for moving tumours. The technique can be ideally combined with the 4D technique (both CT and MRI), but was not implemented in this lab. This project is currently under active testing, as it is very likely to be clinically introduced soon to improve treatments at MCW even further. With this project I learned to work with MIM Software and more about the 4D-CT acquisition procedure.
Describe a ‘typical day’ on your visit.
A typical day started between 8 and 8:30 AM in the office. I shared an office with two Medical Physics residents and two PhD students. A typical workday consisted of software development in either Python, MATLAB, or MIM software, depending on the subproject I worked on. My main contact person was the lab leader Eric Paulson, but also other Medical Physicists were close contacts. The office was close to the coffee machine, where fresh brewed coffee was waiting to be consumed. If I was not fully immersed in my programming projects, I would take a 30 min break around 12:30. In the afternoon the implementation of software continued, and the patient schedule was checked to investigate the machine availability. When certain software was implemented, this was tested at the MR-linac machine. This most often occurred somewhere between 4 and 6 pm.
What were you able to do that you could not have achieved in your home lab?
I was able to shadow clinical practices regarding 4D imaging, where the 4D-MRI in a clinical routine was new to me. In addition, I was able to perform MRI scans in a patient for a multi-institutional manuscript Eric and I are working on (together with others), while in Utrecht I was not able (yet) to scan patients. Furthermore, I was able to implement workflows in MIM software that could be used to improve the image guided radiotherapy in the future. This software has been recently introduced in the clinical routine in my home institute. However, it cannot be used for research purposes yet.
Was there anything you particularly liked about the host institution?
I enjoyed collaborating with the small host group. Because of its small size (compared to what I am used to in my home institute), a weekly meeting with the entire team (PhD student, Post-doc, residents, medical physicists) could be held where ongoing work, feedback and/or ideas were shared between people with different levels of expertise. As a result, it is clearer to the researchers what the broader technical/clinical needs are. Even though the department at MCW is smaller, they still have many different treatment machines. Research regarding these machines were discussed as well in this weekly meeting, which I liked as it was very interesting to hear about.
In my home institute, we have around 45 PhD students in our department. Meetings cannot be held department wide with such numbers, resulting in smaller meetings of PI’s with their research group.
How has the trip inspired you in your research?
This trip has definitely been eye-opening. I have been working in a research group highly focused on the MR-linac for the past five years, which is a very specific and small area in the field of radiotherapy. Sharing an office with two Medical Physics residents that are further along in their career and being in a Radiation Oncology department that is less focused on the MR-linac, has inspired me and made me realise that a broader understanding of the field might be beneficial for my own research. More specifically, we have at MCW been working on an implementation for providing breathing guidance that is independent from the treatment device, which means it can be used during a CT scan, an MRI scan, or a treatment delivery. Breathing guidance software that is compatible with any type of treatment delivery machine is expected to make a significant impact in the radiotherapy field.
Have you brought back any specific knowledge or technique that has benefited your home lab?
Definitely! This department was an early adopter of MIM software to implement so called workflows in the clinic. These workflows process the rich amount of data that is present in the image guided radiotherapy field. Last year, my home institute also started implementing MIM software in the clinic, while the software still has to be introduced in research setting. This visit exposed me to this software and allowed me to develop interesting workflows, which I can apply in my home institute as well. I have been implementing a fully automated workflow to estimate the motion uncertainty based on 4D-CT data. In our institute, we do have an in-house developed version of this that does not use MIM. With the fully automated workflow in MIM that I have developed, it is very likely that this will replace our in-house developed software.
Does your lab plan to do any future collaboration or publication with the host lab?
A collaboration between UMC and MCW for a publication had already been initiated before my visit to MCW. This publication will be submitted soon. During my time at MCW, I developed a more general (visual biofeedback) guidance tool on a Raspberry Pi, which can be used during CT scans and treatment at normal irradiation machines as well. By the time I had to leave, the implementation of this tool had almost been completed. The plan is to finish up the implementation and acquire data in patients at MCW, which hopefully will result in an abstract in either November 2024 or January 2025, when two scientific conferences have their abstract deadlines. Ultimately, this could even result in a publication. Eric and I will also stay in close contact about the (hopefully) clinical introduction of the developed workflow to estimate the motion uncertainty that will lead to smaller treatment volumes.
One of my UMC Utrecht colleagues also developed software to send data from an MRI scanner independently, which I have shared/installed during my visit at MCW. Developments regarding the use of this software will be actively communicated and will lead to publication collaborations when used for research or even clinical use cases.
Want to find out more?
If you are interested in applying for the Travel Fellowship scheme, please click here for more information: EACR Travel Fellowships.
