Irreversible electroporation (IRE) is a local ablation technique that has been shown to be both safe and effective in the treatment of solid tumors. The treatment typically consists of inserting needle electrodes directly into the treatment zone and applying high-voltage pulses with widths on the order of hundreds of microseconds. These pulses permeabilize tissue leading to loss of homeostasis among the cells in the treatment zone. Predicting these treatments is challenging as the electric field (EF) induced through the electrode configuration is heterogeneous and is affected by several adjustable parameters. Computational treatment planning models aim to provide a visualization of the treatment zone, and they rely on two critical pieces of information: the electric field distribution (EFD) within the tissue, and the lethal EF threshold for the target tissue type. This work primarily aims to quantify tissue properties necessary for computing the EFD for any electrode configuration, for both traditional IRE as well as next-generation high-frequency IRE treatments. Also included is the determination of pancreatic tumor lethal EF threshold using collagen tissue mimics. Additionally, this work builds on previous reports of an optimal resistance reached during IRE by examining the changes in patients' immune cell populations following treatment, and proposing a method of optimizing these populations by monitoring real-time current achieved during IRE. / Doctor of Philosophy / We are in dire need of new options in cancer therapy, especially in the treatment of tumors that are unresectable, particularly aggressive, or resistant to drugs. Irreversible electroporation (IRE) is a local tumor treatment that has been shown to safely and effectively destroy tumor tissue while leaving behind important structures like blood vessels. As IRE treatments depend on the electric field (EF) generated within the target tissue, it is difficult for clinicians to predict the amount of tissue that will be treated ahead of time. This work aims to collect and examine the information about tumors and the surrounding healthy tissue that is critical to models that can help visualize the treatment and ensure the tumor is exposed to enough lethal energy. Additionally, a new and improved, high-frequency version of IRE (H-FIRE) is explored in terms of its impact on how tissue behaves during the delivery of these types of pulses. In addition to informing models of these therapies, we also explore strategies that clinicians can employ during treatment in order to know when to stop in order to avoid over-treating the area.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/112171 |
| Date | 23 April 2021 |
| Creators | White, Natalie B. |
| Contributors | Electrical Engineering, Davalos, Rafael V., Jia, Xiaoting, Zhou, Wei, Allen, Irving Coy, Zhu, Yizheng |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf, application/x-zip-compressed |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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