Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Physics

Supervisor

Prof. Blaine Chronik

Abstract

Positron emission tomography (PET) and magnetic resonance imaging (MRI) provide complementary information, and there has been a great deal of research effort to combine these two modalities. A major engineering hurdle is that photomultiplier tubes (PMT), used in conventional PET detectors, are sensitive to magnetic field. This thesis explores the design considerations of different ways of combining small animal PMT-based PET systems with MRI through experimentation, modelling and Monte Carlo simulation. A proof-of-principle hybrid PET and field-cycled MRI system was built and the first multimodality images are shown. A Siemens Inveon PET was exposed to magnetic fields of different strengths and the performance is characterized as a function of field magnitude. The results of this experiment established external magnetic field limits and design studies are shown for wide range of approaches to combining the PET system with various configurations of field-cycled MRI and superconducting MRI systems. A sophisticated Monte Carlo PET simulation workflow based on the GATE toolkit was developed to model the Siemens Inveon PET. Simulated PET data were converted to the raw Siemens list-mode format and were processed and reconstructed using the same processing chain as the data measured on the actual scanner. A general GATE add-on was developed to rapidly generate attenuation correction sinograms using the precise detector geometry and attenuation coefficients built into the emission simulation. Emission simulations and the attenuation correction add-on were validated against measured data. Simulations were performed to study the impact of radiofrequency coil components on PET image quality and to test the suitability of various MR-compatible materials for a dual-modality animal bed.

Readme_root2lst_multi.txt (1 kB)
Readme for the root2lst code

root2lst_multi.cpp (13 kB)
Converts GATE ROOT output to Siemens Inveon listmode output

gate_batch_splitter.pl (1 kB)
Script to split a large GATE simulation into multiple threads

README_NEMA_Phantoms.rtf (1 kB)
Readme for the GATE NEMA phantom macros

phantom_nema_point_source.mac (1 kB)
NEMA NU 4-2008 Point Source Phantom

source_nema_point_source.mac (1 kB)
NEMA NU 4-2008 Point Source Phantom (Source)

phantom_nema_image_quality.mac (21 kB)
NEMA NU 4-2008 Image Quality Phantom

source_nema_image_quality.mac (2 kB)
NEMA NU 4-2008 Image Quality Phantom (Source)

phantom_nema_mouse_scatter.mac (1 kB)
NEMA NU 4-2008 Small Scattering Phantom

source_nema_mouse_scatter.mac (1 kB)
NEMA NU 4-2008 Small Scattering Phantom (Source)

phantom_nema_rat_scatter.mac (1 kB)
NEMA NU 4-2008 Medium Scattering Phantom

source_nema_rat_scatter.mac (1 kB)
NEMA NU 4-2008 Medium Scattering Phantom (Source)

phantom_nema_monkey_scatter.mac (1 kB)
NEMA NU 4-2008 Large Scattering Phantom

source_nema_monkey_scatter.mac (1 kB)
NEMA NU 4-2008 Large Scattering Phantom (Source)

GateAttenuationCorrectionActor.cc (19 kB)
Attenuation Correction Actor

GateAttenuationCorrectionActor.hh (4 kB)
Header for Attenuation Correction Actor

GateAttenuationCorrectionActorMessenger.cc (2 kB)
Messenger Class for AC Actor

GateAttenuationCorrectionActorMessenger.hh (1 kB)
Header for Messenger Class for AC Actor


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