Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Medical Biophysics

Supervisor(s)

Dr. Timothy Scholl

Abstract

Delta relaxation enhanced magnetic resonance (dreMR) is a novel imaging method capable of producing contrast proportional only to the concentration of the bound form of the targetable contrast agent using a dynamic field-cycling technique. The characteristic high relaxivity magnetic field dependence of bound paramagnetic contrast agents enables suppression of tissue contrast from unbound agents and unenhanced tissue, thereby increasing probe specificity. The dreMR technique requires an auxiliary actively shielded field-shifting insert electromagnet to modulate the strength of the main clinical magnetic field as a function of time during the relaxation and evolution periods of a pulse sequence.

Ablavar (approved for human use) binds specifically to serum albumin and has a strong magnetic field dependence for serum albumin around 1.5T. Native biological tissues and unbound Ablavar demonstrate very little magnetic field dependence. Using a custom dreMR preparatory pulse, where the strength of the B0 field is modulated for different times, signal intensity from only the bound form of Ablavar can be produced.

This work entails further advancement of the dreMR method, where we investigate developing the dreMR contrast using phantoms loaded with and without Rabbit Serum Albumin and in vivo imaging using mouse subjects with prostate and breast cancer.


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