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Full-Text Articles in Biomedical Engineering and Bioengineering
A 3d Printed Axon-Mimetic Diffusion Mri Phantom, Tristan K. Kuehn
A 3d Printed Axon-Mimetic Diffusion Mri Phantom, Tristan K. Kuehn
Electronic Thesis and Dissertation Repository
Diffusion MRI is used to non-invasively characterize the microstructure of the brain. However, the accuracy of the characterization is difficult to verify because no other non-invasive imaging modality provides the same information. This thesis presents a novel 3D printed axon-mimetic (3AM) diffusion MRI phantom, a synthetic object designed to mimic the brain's microstructure.
The phantoms were characterized using microscopy, synchrotron micro-computed tomography, and diffusion MRI, and found to have sufficiently axon-mimetic properties to be useful as diffusion MRI phantoms. A set of phantoms designed to have anatomically realistic and complex fibre structures was used to test the response of diffusion …
Incorporating Cardiac Substructures Into Radiation Therapy For Improved Cardiac Sparing, Eric Daniel Morris
Incorporating Cardiac Substructures Into Radiation Therapy For Improved Cardiac Sparing, Eric Daniel Morris
Wayne State University Dissertations
Growing evidence suggests that radiation therapy (RT) doses to the heart and cardiac substructures (CS) are strongly linked to cardiac toxicities, though only the heart is considered clinically. This work aimed to utilize the superior soft-tissue contrast of magnetic resonance (MR) to segment CS, quantify uncertainties in their position, assess their effect on treatment planning and an MR-guided environment.
Automatic substructure segmentation of 12 CS was completed using a novel hybrid MR/computed tomography (CT) atlas method and was improved upon using a 3-dimensional neural network (U-Net) from deep learning. Intra-fraction motion due to respiration was then quantified. The inter-fraction setup …