An exogenous contrast agent has been developed to enhance the contrast achievable in
Thermoacoustic Tomography (TAT). TAT utilizes the penetration depth of microwave
energy while producing high resolution images through acoustic waves. A sample
irradiated by a microwave source expands due to thermoelastic expansion. The acoustic
wave created by this expansion is recorded by an ultrasonic transducer. The water
content in biological samples poses an obstacle, as it is the primary absorber of
microwave radiation. The addition of an exogenous contrast agent improves image
quality by more effectively converting microwave energy to heat. The use of iron oxide
nanoparticles in MRI applications has been explored but super paramagnetic iron oxide
nanoparticles (SPION) have benefits in microwave applications, as well. Through
ferromagnetic resonance, SPION samples more effectively convert microwave energy
into heat. This transduction to heat creates significantly larger thermoacoustic waves
than water, alone. Characterization of the SPION samples is executed through TAT,
TEM, XPS, EDS, and a vector network analyzer with a dielectric probe kit. Onedimensional
and phantom model imaging with an iron oxide nanoparticle contrast agent
provide a two-fold improvement in contrast at current system configurations. Further
enhancement is possible through adjustments to the nanoparticles and TAT system.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1741 |
| Date | 02 June 2009 |
| Creators | Keho, Aaron Lopez |
| Contributors | Meissner, Kenith |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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