Post-doctoral fellow: Real-time in vivo verification of proton therapy

36 hours a week
€ 2.911 - € 4.615

Closing date: June 30

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Working environment

Within the Department of Radiation Oncology of the University Medical Center Groningen (UMCG), Groningen, the Netherlands, we are looking for a motivated and ambitious post-doctoral fellow to join our research on real-time in vivo verification of proton therapy. The UMCG is one of the largest hospitals in the Netherlands, with over 1.300 beds and more than 13.000 employees, taking care of an adherence region of over 2.5 million people. The UMCG is ISO-certified for patient care, teaching, training and research. The University of Groningen is a top 100 university in international rankings. The UMCG foresees a central role for particle therapy in general and proton therapy in particular, both in patient care at the UMCG Groningen Proton Therapy Center and in research. Our strategic research priorities are related to the physics and biology of particle irradiation, with a special focus on proton therapy. This focus fits with the UMCG strengths (state-of-the-art infrastructure) and priorities (focus on healthy aging and on complex pathology).

The successful candidate will be part of the Radiation Physics Group of the Particle Therapy Research Center (PARTREC). PARTREC is embedded in the Departments of Radiation Oncology and Biomedical Sciences of Cells and Systems of the UMCG. The Radiation Physics Group consists of four faculty and several PhD students and post-doctoral fellows, and is an integral part of the Medical Physics and Instrumentation Division of the Department of Radiation Oncology, where over 30 PhD students and post-doctoral fellows are dedicated to particle therapy research. UMCG PARTREC promotes multidisciplinary research in which physics and biology, imaging, big-data analysis and clinical research come together to improve the quality of proton therapy treatment and to explore potential benefits of other particles for cancer treatment. UMCG PARTREC operates a large superconducting cyclotron for experimental research, mainly in radiation physics, medical physics and radiobiology, to support the development of radiotherapy with proton and ion beams ( For this research, the cyclotron delivers beams ranging from protons to oxygen ions with energies up to 190 MeV for protons and 90 MeV per nucleon for ions of helium to oxygen. Some 25 fte technical staff operate the accelerator facility and provide support to design, build and operate experimental apparatus.

The synergy between the UMCG PARTREC research facility and the UMCG Groningen Proton Therapy Center (GPTC) enables the unique combination of technology development, preclinical and patient studies within an R&D program to demonstrate clinical and economic benefits. This offers unique career development opportunities in the field of Medical Physics.

The RIVER project
Proton Pencil Beam Scanning has the potential to reduce dose to healthy tissue while maintaining or increasing the dose to the tumor. This may result in increased cure rates and patient quality-of-life while reducing follow-up health care costs. The potential of proton therapy to spare tissue very close to the tumour (i.e. in the high-dose region) has not yet been fully realized because of treatment-related uncertainties. These uncertainties – range uncertainties, setup errors and anatomical variations in the patient – are presently taken into account via safety margins in robust treatment planning, leading to safe but, unavoidably, not the most optimal treatment plans. In-vivo verification during irradiation is the best approach to reduce safety margins as it closes the loop, for each patient individually, between planned and delivered treatment.

We are investigating imaging of the very short-lived positron-emitting nuclide nitrogen-12 (half-life of only 11 milliseconds), produced in the patient by the therapeutic beam, for real-time in vivo verification. Recently, we obtained very promising results in simple irradiations of simple phantoms. The RIVER project aims to make a major step towards translating nitrogen-12 imaging to the clinic. The following research questions will be answered: What is the precision of nitrogen-12 imaging for in-vivo verification in clinical head-and-neck cancer proton therapy? What reduction in the probability of complications can be achieved, given the demonstrated precision of nitrogen-12 imaging? The first question will be answered on the basis of irradiations of an anthropomorphous head-and-neck phantom which are planned and executed closely following the standard clinical workflow. The irradiations will be performed at the PARTREC research facility ( A treatment planning study of a cohort of previously treated head-and-neck cancer patients, making use of existing normal tissue complication probability (NTCP) models will give an answer to the second question.

Job description

The RayStation treatment planning system that will be used to plan the head phantom irradiations will, next to providing the dose distribution, also predict the distribution of nitrogen-12 positron annihilation. The post-doctoral fellow will set up a Monte Carlo simulation framework (based on Geant4/GATE) to predict the nitrogen-12 images. The post-doctoral fellow will work together with a PhD student (to be hired in the project) on setting up, performing and analysing the head phantom irradiations. Positron imaging data will be collected using a dual-panel positron emission tomograph (PET) provided by Siemens Healthineers. In the analysis, the measured images will be compared to images predicted using Monte Carlo simulations, demonstrating the precision of nitrogen-12 imaging.

Robust treatment planning of a cohort of head-and-neck cancer patients for various safety margins (for range and setup errors) is the topic of a second line of research. Within this topic, the post-doctoral fellow will study how to maximise nitrogen-12 imaging accuracy by optimizing the order of beam delivery and image processing. The outcome of this study will be incorporated in the cohort treatment planning study.

What are we looking for

  • A PhD degree on a topic related to particle beam radiotherapy or a related field.
  • Excellent communication skills.
  • Excellent spoken and written English language skills.
  • Motivation and ambition.
  • Experience in coaching and teaching PhD students is an asset.

Skills and knowledge:

  • MATLAB programming/data analysis;
  • Monte Carlo simulations (preferably Geant4/GATE);
  • radiation transport and detection;
  • positron emission imaging;
  • experiments at accelerator facilities.

The applicants have to be able and willing to work in a radiation environment and should have or will need to quickly obtain the qualification that is required for this. Part of the work will have to be done outside the normal working hours.

The UMCG has a preventive Hepatitis B policy. The UMCG can provide you with the vaccination, should it be required for your position.

In case of specific professions a ‘Certificate of Good Conduct’ is required.

What do we offer

  • A stimulating and creative learning environment.
  • A temporary full-time (1.0 fte) post-doctoral fellow position a period of up to two years. The successful candidate will initially be offered a position for one year; with the extension with a 2nd year conditional on a positive evaluation after 9 months.
  • Your salary will be a maximum of € 4.615,- gross per month (scale 10), depending on your qualifications and relevant experience, based on a full-time appointment. In addition, the UMCG will offer you 8% holiday pay, and 8.3% end-of-year bonus. The conditions of employment comply with the Collective Labour Agreement for Medical Centres (CAO-UMC). English:
  • Employees relocating from abroad may be eligible for the Dutch ‘30% ruling’, a tax advantage which results in a significantly higher net salary.

Applying for a job
Please use the digital application form at the bottom of this page, only these will be processed. The application form requires:

  • Motivation letter.
  • CV (including educational and employment history, academic transcript of the MSc studies, publication list etc.).
  • Name and e-mail address of at least two academic referees.

For questions about the position

Any questions? Do contact us.

dr. Peter Dendooven associate professor


Please use the the digital application form at the bottom of this page - only these will be processed. You can apply until 30 June 2021.
Within half an hour after sending the digital application form you will receive an email- confirmation with further information.


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Do you have any questions?

We would like it if you would contact us if you have any questions about working at UMCG.

Nina van Venrooij
Nina van Venrooij Team Recruitment