6–10 Jul 2026
University of the Western Cape
Africa/Johannesburg timezone
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Geant4 modelling of the beam delivery of a Proteus ONE system for the UCT Proton Therapy Initiative

8 Jul 2026, 10:10
20m
Lecture Hall DL3 (University of the Western Cape)

Lecture Hall DL3

University of the Western Cape

Oral Presentation Track F - Applied Physics Applied Physics

Speaker

Moses Gororo (University of Cape Town)

Description

A team based at the University of Cape Town is well advanced with a project which will return a proton therapy centre to Cape Town, South Africa [1]. The new facility will serve as both a national facility for South Africa and provide access to other countries in the sub-Saharan region. The city of Cape Town offers geographic and technical advantages for the siting of the new centre, which will also benefit from the very latest technological advances in proton therapy [2,3]. In this present work, to support this project, a Monte Carlo model of an IBA Proteus ONE Pencil Beam System (PBS) delivery nozzle has been developed in Geant4.
An appropriate simulation environment, physics models and parameters were selected to produce accurate and efficient simulations [4]. The accuracy of these simulations was validated by obtaining the Bragg Peak for a proton beam energy of 230 MeV in a water phantom, without any devices in the beamline [3]. A modelling method was then developed to simulate a pencil beam delivery system [5]. A degrader was initially added to the beamline to replicate the Proteus ONE PBS beamline technology, before the addition of the bending magnets, scanning magnets, and aperture [6]. Various degrader materials were also included.
The University of Florida Health Proton Therapy Institute (UFHPTI) provided Monte Carlo reference data and experimental data with Integral Depth Dose (IDD) in a phantom box and lateral beam profiles in an air target box, which are compared to the Geant4 results.
The validated Geant4 model accurately reproduces the dosimetric characteristics of the Proteus ONE system and could serve as a foundational tool for secondary dose verification, shielding calculations, and future clinical treatment planning studies [2,6].
References:
1. University of Cape Town (2025) UCT Proton Therapy Initiative. Available at: https://www.news.uct.ac.za/ (Accessed: May 2025).
2. Kraan, A.C. and Del Guerra, A. (2024) ‘Technological developments and future perspectives in particle therapy: A topical review’, IEEE Transactions on Radiation and Plasma Medical Sciences, 8(5), pp. 453–481. https://doi.org/10.1109/TRPMS.2024.3372189
3. Newhauser, W.D. and Zhang, R. (2015) ‘Topical review: the physics of proton therapy’, Physics in Medicine and Biology, 60(8), pp. R155–R209. https://doi.org/10.1088/0031-9155/60/8/R155
4. Arce, P., et al. (2021) ‘Report on G4 Med, a Geant4 benchmarking system for medical physics applications developed by the Geant4 Medical Simulation Benchmarking Group’, Medical Physics, 48(1), pp. 19–56. https://doi.org/10.1002/mp.14503
5. Smith, A., Gillin, M., Bues, M., Zhu, X.R., Suzuki, K., Mohan, R., et al. (2009) ‘The M.D. Anderson proton therapy system’, Medical Physics, 36(9), pp. 4068–4083. https://doi.org/10.1118/1.3187229
6. Bäumer, C., Plaude, S., Khalil, D.A., et al. (2021) ‘Clinical implementation of proton therapy using pencil beam scanning delivery combined with static apertures’, Frontiers in Oncology, 11, 599018. https://doi.org/10.3389/fonc.2021.599018

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Author

Moses Gororo (University of Cape Town)

Co-authors

Andy Buffler (University of Cape Town) Graham Fieggen (University of Cape Town) Jacqui Bacher (University of Cape Town) Jeannette Parkes (University of Cape Town) Steve Peterson (University of Cape Town) Tom Leadbeater (MeASURe, Department of Physics, University of Cape Town)

Presentation materials