Browsing by Subject "Medical imaging"

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    Functional Neuroimaging of Electrophysiological Rhythms in Pathological and Normal Brains
    (2012-07) Yang, Lin
    Imaging of electrophysiological activity in the brain plays a critical role in neuroscience research. Shown by emerging neuroimaging studies, rhythmic oscillations in electrophysiology reflect important functional changes in the brain. More importantly, the mapping of electrophysiological neural signals can serve as a diagnostic tool for neurological diseases. One typical example is the electroencephalography (EEG) technique, which has been established as a core component of pre-surgical evaluation in epilepsy treatment. However, despite the recent advances of functional neuroimaging techniques, a non-invasive, high resolution, electrophysiological imaging approach still remains challenging. In the clinical application of epilepsy, there is not an established protocol that can image, non-invasively, the electrophysiological signals during the most important epileptic event - epileptic seizures. The present dissertation research aims at developing electrophysiological imaging approaches with focus on the rhythmic activity in pathological and normal brains. Towards this goal, we have developed a spatiotemporal EEG imaging method, which is suited to image dynamic changes of ictal discharges during epileptic seizures. As evaluated in a group of epilepsy patients in clinical environment, such a non-invasive seizure imaging approach could potentially translate into a more precise and less risky pre-surgical imaging tool for epilepsy diagnosis. In addition to the direct impact of seizures, we have studied the electrophysiological changes in the widespread brain networks. The spatial and spectral features of EEG rhythms can reflect important correlation with the impact of seizures and the change of cognitive functions. The electrophysiological imaging in epilepsy, therefore, can serve as a useful tool in a pathological model to study cognition and consciousness in human brains. In order to achieve higher spatial resolution, we also improved the EEG source imaging by adding a multimodal component of functional MRI. From all the results we have obtained so far in these studies, it is suggested that the spatiotemporal EEG source imaging has the potential to improve clinical diagnosis and treatment of neurological disorders. It can also advance our understanding of basic neuroscience questions.
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    Molecular Imaging of Prostate Cancer Using Biomarker-Guided Strategies
    (2019-08) Shapovalova, Mariya
    Prostate cancer affects 1 in 9 men in their lifetime. While disease that is detected early can be very treatable, recurrence affects about 30% of the patients. Imaging is an important tool for detecting and assessing therapeutic regimens for prostate cancer patients. Patients with advanced stages of prostate cancer, typically those who have had a recurrence and are forming resistance to hormone therapy, are in a great need for a more accurate assessment of the extent of their disease for a better understanding of its aggressiveness. Clinical imaging offers physicians information about the location and extent of disease. Unfortunately, conventional imaging methods often lack the sensitivity needed to detect some lesions properly, especially when the disease is no longer localized and has spread outside of the prostate, which leads to insufficient information that is needed for proper diagnosis and treatment planning. Most of the current imaging techniques are not specific for tumor physiological processes. Therefore, a clinical need remains for new imaging agents that can target prostate tumors more specifically and sensitively. My PhD research focused on using molecular-genetic imaging approaches to develop imaging agents in vitro and in vivo that can detect prostate cancer using the cancer's unique regulatory genetic differences from normal cells. I investigated the expression two prostate cancer-specific genes, AMACR and PEG10 and used the genes' unique transcriptional regulations in the prostate cancer cells to induce prostate cancer-specific expression of reporter proteins. Specifically, I used the promoters of AMACR and PEG10 in adenovirus and plasmid DNA vectors upstream of various reporter genes to induce expression of reporter proteins in prostate cancer cells. By using the prostate cancer-specific promoters, I was able to image prostate cancer in vivo using various vectors and different modes of imaging such as bioluminescence/fluorescence and positron emission tomography imaging. My results strongly support that prostate cancer specific promoters can induce prostate cancer specific gene expression and may have the potential to be used for imaging purposes.