Magnetomotive optical coherence tomography and elastography with applications in magnetic thermotherapy dosimetry

Magnetic nanoparticles (MNPs), with their versatility, have raised extensive interest in the field of biomedicine. MNPs can be delivered to the tumors as therapeutic agents in magnetic thermotherapy (MT) to ablate the malignancies. Remotely manipulated with an external magnetic field, the same MNPs can also induce “magnetomotions”, which can be detected via magnetomotive optical coherence tomography (MM-OCT) and enable biomechanical characterization with magnetomotive optical coherence elastography (MM-OCE). In this thesis, the theranostic functionality of MNPs are exploited, where the biomechanical alterations of the MT-treated tissues were probed by MM-OCE; thereby providing a biophysically informative evaluation of the thermal damage. Treated with MNP hyperthermia, the elasticity changes were qualitatively measured based on the natural/resonant frequency detected by transient-response or spectroscopic MM-OCE. Interstitial MT was provided using a magnetic thermoseed, and the thermally perturbed tissue stiffness was quantified with shear-wave MM-OCE. From ex vivo porcine livers, a linear correlation between the stiffness increase and the thermal energy deposited was observed, offering physical meanings to the elasticity-based metric. In addition, in vivo MM-OCE-based elastograms were generated, for the first time, with an accelerated MM-OCE platform developed with a single chirped force excitation, rapid BM-mode scanning, and parallel-programming-based image reconstruction. Finally, the association between the tissue elasticity, the fundamental biological variations (i.e. tumor cellularity, protein conformation forms), and the MT-induced temperature rise was characterized on in vivo murine melanoma tumors. It was observed that tumors with lower cellularity can be softened after MT treatment. In contrast, depending on the temperature rise achieved and the conformation forms of the collagen fibers, highly cellular tumors can be stiffened either reversibly or irreversibly. In summary, theranostic MNPs can be delivered to the tumors and tracked by MM-OCT imaging. The MT-induced biomechanical alteration (which is related to the intrinsic biological features and molecular changes) can then also be characterized with MM-OCE.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Bioengineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2021

Author dc:creator

• Huang, Pin-Chieh

Contributors dc:contributor

• Boppart, Stephen A
• Insana, Michael F
• Sutton, Bradley P
• Sobh, Nahil A

• Optical coherence tomography
• Elastography
• Magnetic nanoparticles
• Magnetic hyperthermia

Statement dc:rights

• Copyright 2020 Pin-Chieh Huang

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/109607

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/109607