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Cook H, Simard M, Niemann N, Gillies C, Osborne M, Hussein M, Rompokos V, Bouchard H, Royle G, Pettingell J, Palmans H, Lourenço A. Development of optimised tissue-equivalent materials for proton therapy. Phys Med Biol 2023; 68. [PMID: 36696694 DOI: 10.1088/1361-6560/acb637] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 01/25/2023] [Indexed: 01/26/2023]
Abstract
Objective. In proton therapy there is a need for proton optimised tissue-equivalent materials as existing phantom materials can produce large uncertainties in the determination of absorbed dose and range measurements. The aim of this work is to develop and characterise optimised tissue-equivalent materials for proton therapy.Approach. A mathematical model was developed to enable the formulation of epoxy-resin based tissue-equivalent materials that are optimised for all relevant interactions of protons with matter, as well as photon interactions, which play a role in the acquisition of CT numbers. This model developed formulations for vertebra bone- and skeletal muscle-equivalent plastic materials. The tissue equivalence of these new materials and commercial bone- and muscle-equivalent plastic materials were theoretical compared against biological tissue compositions. The new materials were manufactured and characterised by their mass density, relative stopping power (RSP) measurements, and CT scans to evaluate their tissue-equivalence.Main results. Results showed that existing tissue-equivalent materials can produce large uncertainties in proton therapy dosimetry. In particular commercial bone materials showed to have a relative difference up to 8% for range. On the contrary, the best optimised formulations were shown to mimic their target human tissues within 1%-2% for the mass density and RSP. Furthermore, their CT-predicted RSP agreed within 1%-2% of the experimental RSP, confirming their suitability as clinical phantom materials.Significance. We have developed a tool for the formulation of tissue-equivalent materials optimised for proton dosimetry. Our model has enabled the development of proton optimised tissue-equivalent materials which perform better than existing tissue-equivalent materials. These new materials will enable the advancement of clinical proton phantoms for accurate proton dosimetry.
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Affiliation(s)
- H Cook
- Department of Medical Physics and Biomedical Engineering, University College London, WC1E 6BT, United Kingdom
- Medical Radiation Science, National Physical Laboratory, Teddington, TW11 0LW, United Kingdom
| | - M Simard
- Department of Medical Physics and Biomedical Engineering, University College London, WC1E 6BT, United Kingdom
- Centre de recherche du CHUM, 900 Saint Denis St, Montreal, Quebec H2X 0A9, Canada
- University of Montreal, 2900 Edouard Montpetit Blvd, Montreal, Quebec H3T 1J4, Canada
| | - N Niemann
- Barts Health NHS Trust, Clinical Physics Department, London, E1 2BL, United Kingdom
| | - C Gillies
- Medical Physics Department, Proton Therapy Centre, University College Hospital, WC1E 6AS, United Kingdom
| | - M Osborne
- Medical Physics Department, The Rutherford Cancer Centre Thames Valley, Reading, RG2 9LH, United Kingdom
| | - M Hussein
- Department of Medical Physics and Biomedical Engineering, University College London, WC1E 6BT, United Kingdom
- Medical Radiation Science, National Physical Laboratory, Teddington, TW11 0LW, United Kingdom
| | - V Rompokos
- Medical Physics Department, Proton Therapy Centre, University College Hospital, WC1E 6AS, United Kingdom
| | - H Bouchard
- Centre de recherche du CHUM, 900 Saint Denis St, Montreal, Quebec H2X 0A9, Canada
- University of Montreal, 2900 Edouard Montpetit Blvd, Montreal, Quebec H3T 1J4, Canada
| | - G Royle
- Department of Medical Physics and Biomedical Engineering, University College London, WC1E 6BT, United Kingdom
| | - J Pettingell
- Medical Physics Department, The Rutherford Cancer Centre Thames Valley, Reading, RG2 9LH, United Kingdom
| | - H Palmans
- Medical Radiation Science, National Physical Laboratory, Teddington, TW11 0LW, United Kingdom
- Medical Physics Group, MedAustron Ion Therapy Centre, A-2700 Wiener Neustadt, Austria
| | - A Lourenço
- Department of Medical Physics and Biomedical Engineering, University College London, WC1E 6BT, United Kingdom
- Medical Radiation Science, National Physical Laboratory, Teddington, TW11 0LW, United Kingdom
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