Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Science

Program

Medical Biophysics

Supervisor

Foster, Paula

Abstract

Magnetic particle imaging (MPI) is an emerging imaging modality that specifically detects superparamagnetic iron oxide nanoparticles (SPIOs). Our lab has shown that cell tracking with magnetic resonance imaging (MRI) has very high sensitivity, but low specificity and quantification of iron labeled cells is difficult. MPI cell tracking could overcome these limitations. A MomentumTM MPI system was installed at Robarts in August 2019 and this is the first project to be completed using MPI. In Chapter 2 a series of in vitro experiments are reported which tested the repeatability and reproducibility of imaging SPIO labeled cell samples. There are no reports of the use of micron-sized iron oxide particles (MPIO) for cell tracking by MPI. Therefore, in Chapter 3, MPIO was evaluated for in vivo detection and quantification of cancer cells in the mouse brain by MPI. In Chapter 4, limitations of these studies and plans for future work are discussed.

Summary for Lay Audience

The purpose of this thesis is to explore a new imaging tool called magnetic particle imaging (MPI) to study its ability to detect iron-labeled cancer cells that have been dispersed in the brain or cell samples. MPI directly detects iron oxide nanoparticles and can be used to provide a measure of the iron content and number of iron labeled cells in the brain. Since MPI is so new it is not known what type of iron particle will be ideal for cell detection. I explore two different iron particles in this thesis. I labeled breast cancer cells that spread to the brain with large micron-sized iron oxide particles and studied how well these cells could be detected. I compared this particle with the current gold standard for MPI which is called Vivotrax. Experiments were conducted on iron labeled cell samples to determine ways to improve image quality, to see if MPI would damage cells during scanning, and to compare how imaging and analysis were affected when different users conducted scans and analyzed the same data. Iron labeled cancer cells were then injected into mice to see how well MPI would be able to detect cells that were dispersed in a mouse brain. Images from MPI and MRI were compared to determine the benefits and limitations of these complementary imaging tools. Major limitations of the studies and ideas for future work are also discussed.

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