Unsicherheiten in der Reichweitevorhersage limitieren wesentlich das Ausnutzen der Vorteile von Protonentherapie gegenüber konventioneller Strahlentherapie. Die Verwendung von Zwei-Spektren-Computertomographie (DECT) zur direkten Vorhersage des Bremsvermögen (DirectSPR) ermöglicht eine relevante Verbesserung der Reichweitevorhersage gegenüber der üblicherweise verwendeten Ein-Spektren-Computertomographie (SECT). Im Rahmen dieser Dissertation wurde die Variation in der Reichweitevorhersage zwischen 17 europäischen Partikeltherapiezentren experimentell verglichen. Die Genauigkeit der Reichweitevorhersage bei Verwendung einer DirectSPR-Implementierung wurde umfassend quantifiziert und die Implementierung in die klinische Routine integriert. Dies führte zu einer Reduzierung des klinischen Sicherheitssaum um ca. 35% für die Behandlung von quasistatischen Tumoren in Kopf und Becken und damit einer Schonung des Normalgewebes sowie der das Zielgebiet umgebenden Risikoorgane. Darüber hinaus wurde die DirectSPR-Implementierung zur Bestimmung von Gewebeparametern sowie deren Variabilität für zehn Organe im Kopf und Becken in einer Patienkohorte genutzt. Die vorgestellten Ergebnisse etablieren DECT weiter als zukünftiges Standard-Bildgebungsverfahren in der Partikeltherapie.:1. Introduction
2. Proton therapy
2.1. Physical principles of proton therapy
2.2. Treatment with protons
2.3. Accuracy in proton therapy
3. CT Imaging for proton therapy
3.1. Principles of CT imaging
3.2. CT-based range prediction
3.3. Investigated phantoms and materials
3.4. DECT scan acquisition
3.5. Determination of proton stopping power for reference materials
4. Accuracy of stopping-power prediction in European proton centres
4.1. Study design
4.2. Experimental setup and analysis
4.3. Results
4.4. Discussion of determined deviations
4.5. Conclusion and outlook
4.6. Establishment of guidelines for HLUT calibration
5. Range uncertainties in DirectSPR-based treatment planning
5.1. Clinical implementation of DirectSPR
5.2. Uncertainty quantification
5.3. Resulting uncertainties in SPR prediction
5.4. Experimental validation
5.5. Dosimetric effect of range uncertainty reduction
5.6. Discussion
6. In-vivo tissue characterisation using DirectSPR
6.1. Tissue parameter determination by Woodard and White
6.2. Data preparation and analysis
6.3. Determined tissue parameters and variations
6.4. Discussion
7. The future of image-based range prediction
7.1. Particle imaging
7.2. Creation of synthetic CT images
7.3. Photon-counting computed tomography
8. Summary
9. Zusammenfassung
A. Supplement
A.1. Investigated materials
A.2. EPTN study: Individual results
A.3. DirectSPR validation results / Imaging-related range uncertainties effectively limit the full exploitation of the benefits proton therapy offers with respect to conventional photon radiotherapy. The use of dual-energy computed tomography (DECT) for direct stopping-power prediction (DirectSPR) was determined to provide relevant improvements in range prediction over commonly used singleenergy CT (SECT). Within this thesis, the variation in range prediction accuracy between 17 European particle treatment centres were experimentally quantified to determine the current status quo in the community. The overall range uncertainty when using a DirectSPR implementation in treatment planning was comprehensively quantified and the implementation integrated into the clinical workflow. This led to a reduction of clinical safety margins by about 35% for the treatment of quasi-static tumours in the head and pelvis, effectively reducing the dose to surrounding healthy tissue and organs at risk. The DirectSPR implementation was furthermore utilised to assess tissue parameters and their inter- and intra-patient variability for ten organs in the head and pelvis from a cohort of patients. The presented results further establish DirectSPR as the future standard imaging modality in particle therapy.:1. Introduction
2. Proton therapy
2.1. Physical principles of proton therapy
2.2. Treatment with protons
2.3. Accuracy in proton therapy
3. CT Imaging for proton therapy
3.1. Principles of CT imaging
3.2. CT-based range prediction
3.3. Investigated phantoms and materials
3.4. DECT scan acquisition
3.5. Determination of proton stopping power for reference materials
4. Accuracy of stopping-power prediction in European proton centres
4.1. Study design
4.2. Experimental setup and analysis
4.3. Results
4.4. Discussion of determined deviations
4.5. Conclusion and outlook
4.6. Establishment of guidelines for HLUT calibration
5. Range uncertainties in DirectSPR-based treatment planning
5.1. Clinical implementation of DirectSPR
5.2. Uncertainty quantification
5.3. Resulting uncertainties in SPR prediction
5.4. Experimental validation
5.5. Dosimetric effect of range uncertainty reduction
5.6. Discussion
6. In-vivo tissue characterisation using DirectSPR
6.1. Tissue parameter determination by Woodard and White
6.2. Data preparation and analysis
6.3. Determined tissue parameters and variations
6.4. Discussion
7. The future of image-based range prediction
7.1. Particle imaging
7.2. Creation of synthetic CT images
7.3. Photon-counting computed tomography
8. Summary
9. Zusammenfassung
A. Supplement
A.1. Investigated materials
A.2. EPTN study: Individual results
A.3. DirectSPR validation results
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:78776 |
| Date | 08 April 2022 |
| Creators | Peters, Nils |
| Contributors | Enghardt, Wolfgang, Korreman, Stine, Technische Universität Dresden |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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