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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Compton Camera for In-vivo Dosimetry in Ion-beam Radiotherapy

Kormoll, Thomas 22 February 2013 (has links)
In dieser Arbeit wird die Bildgebung durch eine Compton-Kamera zur Überwachung der Partikelstrahlentherapie erstmals an der Technischen Universität Dresden untersucht. Die inhärenten Beschränkungen der Methode wurden durch Berechnungen und Monte Carlo Simulationen studiert. Im Zuge dieser Untersuchungen erschien der Raumtemperatur-Halbleiter Cadmium Zink Tellurid als ein vielversprechendes Detektor-Material. Zur weiteren Untersuchung wurde eine einfache Compton-Kamera konstruiert bestehend aus einem Cadmium Zink Tellurid Detektor und einem ortsempfndlichen Szintillationsdetektor. Das System hat gezeigt, dass eine akkurate Bildgebung mit radioaktiven Punktquellen unter Laborbedingungen möglich ist. Weitere praktische Beschränkungen der Compton-Bildgebung unter Strahlbedingungen konnten durch Experimente an einem Protonen-Strahl hergeleitet werden. Durch die experimentellen Erfahrungen mit der in dieser Arbeit entwickelten Compton-Kamera konnten wertvolle Informationen gesammelt werden, die erlauben, die Bildrekonstruktion zu evaluieren und dazu beitragen, die weitere Forschung hin zu einer klinisch anwendbaren Compton-Kamera zu leiten.:Abstract/Zusammenfassung Illustration Index Index of Tables List of Abbreviations 0 Introduction 0.1 Motivation 0.2 Task 1 Physical Background 1.1 Interaction of Ionizing Radiation with Matter 1.1.1 Coherent Photon Scattering 1.1.2 Incoherent Photon Scattering 1.1.3 Complete Absorption in the Nuclear Electric Field 1.1.4 Pair Production 1.1.5 Total Photon Cross Section 1.1.6 Directly Ionizing Radiation 1.2 Prompt Gamma-rays from Nuclear Reactions 1.3 Detector Technology 1.3.1 Semiconductor Detectors 1.3.2 Scintillation Detectors 1.4 Compton Imaging 1.4.1 Image Formation 1.4.2 History and Application of Compton Cameras 1.5 Prompt Gamma-ray Imaging for In-vivo Dosimetry – Work of Other Groups 2 Design Study 2.1 Introduction 2.1.1 Emission Spectra – Available Data 2.2 Materials and Methods 2.2.1 Angular Resolution 2.2.2 Efficiency 2. Results 2.4 Conclusions 3 Prototype System 3.1 Overview 3.2 System Components 3.2.1 CdZnTe Detector and its Front-end-electronics 3.2.2 LSO Block-Detector 3.2.3 Mounting Frame 3.2.4 DAQ Hardware and Software 3.3 Results 3.3.1 Detector Performance 3.3.2 System Performance 3.4 Conclusions 4 Beam Experiments 4.1 Introduction 4.2 Materials and Methods 4.3 Results 4.3.1 Source Test 4.3.2 Beam Profile 4.3.3 Trigger Rate 4.3.4 Pixel Selection in the LSO 4.3.5 Phantom Measurement 4.4 Conclusions 5 Discussion Appendix A A.1 Technical Drawing of the CdZnTe Electrode Layout Bibliography Danksagung Erklärung / This work presents the first efforts at the Dresden University of Technology to study the feasibility of Compton imaging as a modality to monitor ion beam radiation therapy. The inherent limitations of the method have been studied by means of calculation and Monte Carlo simulation. As a result, the room-temperature semiconductor cadmium zinc telluride appeared as a promising detector material for a clinical device. For more detailed investigation, a simple Compton camera has been constructed comprising a cadmium zinc telluride detector and a position sensitive scintillation detector. This system has proven that accurate imaging of radioactive point sources in the laboratory is feasible. More practical restrictions of Compton imaging in beam conditions have been derived through experiments at a proton facility. Through the experimental work with the Compton camera developed in this work, valuable information was gathered which allowed to test the image reconstruction and to direct the further research towards a clinical Compton camera system.:Abstract/Zusammenfassung Illustration Index Index of Tables List of Abbreviations 0 Introduction 0.1 Motivation 0.2 Task 1 Physical Background 1.1 Interaction of Ionizing Radiation with Matter 1.1.1 Coherent Photon Scattering 1.1.2 Incoherent Photon Scattering 1.1.3 Complete Absorption in the Nuclear Electric Field 1.1.4 Pair Production 1.1.5 Total Photon Cross Section 1.1.6 Directly Ionizing Radiation 1.2 Prompt Gamma-rays from Nuclear Reactions 1.3 Detector Technology 1.3.1 Semiconductor Detectors 1.3.2 Scintillation Detectors 1.4 Compton Imaging 1.4.1 Image Formation 1.4.2 History and Application of Compton Cameras 1.5 Prompt Gamma-ray Imaging for In-vivo Dosimetry – Work of Other Groups 2 Design Study 2.1 Introduction 2.1.1 Emission Spectra – Available Data 2.2 Materials and Methods 2.2.1 Angular Resolution 2.2.2 Efficiency 2. Results 2.4 Conclusions 3 Prototype System 3.1 Overview 3.2 System Components 3.2.1 CdZnTe Detector and its Front-end-electronics 3.2.2 LSO Block-Detector 3.2.3 Mounting Frame 3.2.4 DAQ Hardware and Software 3.3 Results 3.3.1 Detector Performance 3.3.2 System Performance 3.4 Conclusions 4 Beam Experiments 4.1 Introduction 4.2 Materials and Methods 4.3 Results 4.3.1 Source Test 4.3.2 Beam Profile 4.3.3 Trigger Rate 4.3.4 Pixel Selection in the LSO 4.3.5 Phantom Measurement 4.4 Conclusions 5 Discussion Appendix A A.1 Technical Drawing of the CdZnTe Electrode Layout Bibliography Danksagung Erklärung

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