Date of Graduation

12-2016

Document Type

Thesis

Degree Name

Bachelor of Science in Electrical Engineering

Degree Level

Undergraduate

Department

Electrical Engineering

Advisor

El-Shenawee, Magda

Abstract

This thesis presents the work performed to develop tissue phantoms and a contrast agent that will be used in future research of terahertz time-domain imaging of breast tumor margins. Since an excised breast tumor can contain healthy fibrous and fatty tissues along with invasive ductal carcinoma (IDC), three phantom materials were developed. Solid phantom materials were made by using TX151 to solidify water in order to tune the refractive index and absorption coefficient of the fibrous tissue phantom and IDC phantom to the properties of freshly excised breast tissue. Various amounts of olive oil were added to the water prior to solidification to achieve these properties. As the fat tissue phantom required too much olive oil, a commercially available material was found that match the optical properties of fresh breast tissue. Both the refractive index and the absorption coefficient of the three phantoms were verified through the use of time-domain terahertz spectroscopy performed on the pulsed terahertz system at the University of Arkansas.

The proposed terahertz contrast agent was chosen from a group of carbon-based particles which included high pressure, high temperature synthetic diamond particles and onion-like carbon (OLC). To test the contrast agent, polyethylene tablets containing a known concentration of these particles were characterized using the time-domain terahertz spectroscopy. Two sizes of OLC (100-200nm) and five sizes of diamond particles (1-150um) were tested to determine the effects of varying particles sizes. Additionally, diamond particles with three types of treatments (pristine, irradiated and irradiated-annealed) were tested to determine what effects, if any, the treatments had. The particles effeteness as a contrast agent in lossy phantom tissue was tested by incorporating them into IDC phantoms. The results show that the 100nm OLC had potential as a terahertz contrast agent in breast cancer.

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