Speaker
Description
Authors
L. Aranda 1,2, D.F. Redaelli 3, T. Underwood 3,4, A. Hoffmann 1,2,5
Affiliations
1 - OncoRay, National Center for Radiation Research in Oncology, Dresden, 2 - Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, 3 - Research Department, Leo Cancer Care Ltd, 4 - Department of Medical Physics and Biomedical Engineering, University College London, 5 - Dresden University of Technology (TUD), Dresden
Objective
Upright patient positioning is evolving in the radiotherapy sector, with systems designed for both photon and proton treatments using a fixed beamline. The development of a new upright patient positioning system (UPPS) is currently underway for MR-guided proton therapy at OncoRay, Dresden. The installed imaging system is an ASG MR scanner: a rotatable, 0.5T, full-body device that introduces the possibility of upright, real-time patient imaging for gated treatment, when a fixed beamline is aligned with the scanner entry portal.
The intended application is for paediatric cranio-spinal irradiation (CSI), addressing either the full cranio-spinal region or the cranial space alone. However, before we can design an MR-compatible and comfortable UPPS, we need to know which children fit within the scanner's spatial constraints, yet no method currently exists to accurately model a target population. We therefore set out to establish a representative modelling method to support initial ergonomic and patient-fitting assessments and to define the target patient size range.
Methods
First, we gathered relevant anthropometric data from several published sources into a single dataset. Using scripting methods and Blender v5.1, we were able to improve the correlation and interpretability between variable definition and human model creation where we introduced a means of mapping between model input and output.
Results
The collected anthropometric data were input into the model and can now be used to predict the software variables defining a given stature. We further validated the dimensional accuracy of the generated models, which lies within a 0.5% error. Stature and the sitting-height-to-stature (SH/S) ratio were identified as the key dimensions, with the lower body emerging as the limiting factor within the available space, as the SH/S ratio decreases with age (towards ~0.52), the proportionally longer-legged older children reach this limit first.
Outlook & Discussion
From this study, we now have the ability to create accurate models from anthropometric data using commercial software and produce virtual representations of the expected CSI treatment scenario to allow the constraints of the UPPS to be visualised. This addresses the gap that previously prevented population-representative fitting assessments for our MR system. The question of which children can be accommodated is not yet fully answered, but this work unlocks the next step towards designing a first-generation UPPS for MR-guided proton therapy.
Acknowledgements
This work is part of the UPLIFT project and funded by the European Union under Grant Agreement No. 101168955.