Ir. K. (Kelvin) Ng Wei Siang, PhD

About me

I am a Dutch certified Medical Physicist and assistant professor specializing in proton therapy research, with a focus on enhancing treatment outcomes and minimizing toxicity. My primary research revolves around the development of proton minibeam radiotherapy (pMBRT) and spatially fractionated radiotherapy (SFRT), which have shown significant promise in sparing healthy tissues in preclinical models. Additionally, I explore proton therapy applications for brain, liver, cholangiocarcinoma, pelvic, anal, and vulvar cancers, as well as advancements in treatment planning and modeling. My experience in QA validation, treatment planning, evaluations, and active contributions to clinical trials support my goal of improving patient care through innovative radiotherapy techniques.

Professional activities

I currently lead the group and research for SFRT at Erasmus MC and HollandPTC. With a background in clinical science and extensive collaboration with both national and international research groups, and chair of the Dutch Commission on Radiation Dosimetry for small field dosimetry and leading the ESTRO physics workshop SFRT survey group, I am deeply committed to advancing proton therapy techniques. I currently lead research projects within the PRESTO consortium and supervise PhD candidates and masters students working on advancing proton therapy with cutting-edge radiotherapy protocols. My activities are dedicated to bridging the gap between innovative research and clinical application, ensuring more efficient and effective treatment for cancer patients.

Research Focus Areas:

• Proton Therapy: Investigating the application and optimization of proton therapy to improve tumor targeting while minimizing damage to surrounding healthy tissues.
• Proton Minibeam Radiotherapy (pMBRT): Developing a novel radiotherapy technique using small proton beams (minibeams) to spare healthy tissues significantly, with promising results in preclinical models.
• Spatially Fractionated Radiotherapy (SFRT): Exploring SFRT to enhance tumor control while reducing normal tissue toxicity, particularly for complex cancers like brain and head and neck tumors.
• Radiotherapy Techniques Innovation: Advancing and refining radiotherapy methodologies to improve dose distribution, treatment planning, and patient-specific therapy.
• Cancer Types: Applying proton therapy to various cancers, including brain, liver, cholangiocarcinoma, and pelvic (anal and vulvar) cancers, with a focus on personalized treatment.
• Treatment Planning and Modeling: Creating advanced computational models for optimal treatment planning and ensuring precision in proton therapy delivery.
• QA Validation: Performing quality assurance (QA) validation to verify treatment protocols and radiation delivery accuracy.

Research Activities:

• Development of Radiotherapy Techniques: Leading research on next-generation radiotherapy techniques like pMBRT and SFRT, aimed at improving tumor control and reducing normal tissue damage.
• Preclinical Modeling: Conducting studies on animal tissue to simulate and validate new radiotherapy techniques, focusing on the efficacy and safety of proton therapy in different cancer types.
• Advanced Proton Therapy Applications: Investigating innovative applications of proton therapy, including its integration with other treatment modalities and optimization in clinical settings.
• Clinical Validation and QA for Proton Therapy: Ensuring the accuracy and safety of proton therapy through rigorous clinical trials, validation procedures, and quality assurance.

Education

2019-2023: Medical Physicist Expert in training at UMCG, Groningen 
2019-2019: University of Groningen, M.Sc. in Applied Physics (completed within 6 months), thesis title: Validating Monte Carlo Calculations of Clinical Proton Beams in Animal Tissue Phantoms, thesis score 9/10. Total score 9/10
2012-2016: University of Technology, Delft, Ph.D. in Material Science and Physics, thesis title: July 07th, 2016
2016-2010: Nanyang Technological University, BEng in Aerospace Engineering

Professional experience

2026-present: Assistant Professor, Erasmus MC
2025-present: Knowledge Exchange and Outreach Associate, PRESTO consortium
2023-present: Medical Physicist Expert at the Erasmus MC, department of Radiotherapy (start mid-May 2023)
2023-present: Medical Physicist Expert at the HollandPTC, department of Radiotherapy
2019-2019: Proton Physicist at University Medical Center, Groningen
2017-2019: Lead Engineer, Data Health Scientist at ASML, Veldhoven
2016-2017: Metrology Design Engineer at ASML, Veldhoven

Selected publications

1. Prins AC, Traneus E, Hoogeman MS, Ng Wei Siang K. Impact of center-to-center distance and slit width on robust target coverage and PVDR for proton minibeam radiation therapy using a commercial TPS. Med Phys. 2026; e70340. doi:10.1002/mp.70340.
2. Oud M, Breedveld S, Ng Wei Siang K, et al. A planning approach for online adaptive proton therapy to cope with cone beam computed tomography inaccuracies. Phys Imaging Radiat Oncol. 2025 Mar 20;34:100752. doi:10.1016/j.phro.2025.100752
3. Ng Wei Siang K, Both S, Oldehinkel E, Langendijk JA, Wagenaar D. Assessment of residual geometrical errors of clinical target volumes and their impact on dose accumulation for head and neck radiotherapy. Radiother Oncol. 2023;188:109856. doi:10.1016/j.radonc.2023.109856.
4. Guterres Marmitt G, Pin A, Ng Wei Siang K, et al. Platform for automatic patient quality assurance via Monte Carlo simulations in proton therapy. Phys Med. 2020;70:49-57. doi:10.1016/j.ejmp.2019.12.018 
5. Meijers A, Guterres Marmitt G, Ng Wei Siang K, et al. Feasibility of patient specific quality assurance for proton therapy based on independent dose calculation and predicted outcomes. Radiother Oncol. 2020 Sep;150:136-141. doi:10.1016/j.radonc.2020.06.027.

2021-2024: Advance Medical Visualization with deep learning RT applications for 2nd year biomedical engineering masters at UMCG. 
2021-2024: Thesis examiner for the faculty at  UMCG. 
2023-present: Lecturer for the course ”Medical Physics in Radiation Oncology” for year 1 masters student at TU Delft
2024-present: Medical Statistics for Erasmus MC Academy

Present: Pianoforte Partnership Grant awarded for PRESTO-consortium, for PRoton therapy Enhancement by Spatially fractionated Treatment Optimization
2025:  Awarded €17,000 by the Vaillant foundation via the HollandPTC foundation for pilot collimator prototype development for pMBRT at HollandPTC
2025:  Awarded €10,000 by the ANS foundation via the HollandPTC foundation for pilot collimator prototype developments for pMBRT at HollandPTC
2019: Cum Laude, Applied Physics, University of Groningen, The Netherlands 
2010: Valedictorian, Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
2010: Lee Kwan Yew Gold Medal for academic excellence, Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
2010: Koh Boon Kwan Gold Medal for best collaboration between teaching staff and student, Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
2010: Defence Science and Technology, Gold Medal for Best Technical Student, Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore