Oncology Commons^™

Acute Pharmacologic Modulation Of Glioblastoma Ph Monitored By Chemical Exchange Saturation Transfer Magnetic Resonance Imaging, Mohammed Albatany

Electronic Thesis and Dissertation Repository

The response of tumor intracellular pH (pH_i) to a pharmacological challenge could help identify aggressive cancer. In addition, tumor pH_i may influence cell proliferation, apoptosis, chemotherapy resistance, and thermosensitivity. Chemical exchange saturation transfer (CEST) is a novel MRI contrast mechanism that is sensitive to cellular pH. More specifically, a CEST method called amine and amide concentration-independent detection (AACID) produces images weighted by intracellular pH (pH_i) and can be used to study pharmacologic pH modulation in tumours.

The overall goal of this thesis was to maximize the magnitude of intracellular tumour acidification using pharmacologic agents. Several …

Developments In Pet-Mri For Radiotherapy Planning Applications, John Christian Patrick

Electronic Thesis and Dissertation Repository

The hybridization of magnetic resonance imaging (MRI) and positron emission tomography (PET) provides the benefit of soft-tissue contrast and specific molecular information in a simultaneous acquisition. The applications of PET-MRI in radiotherapy are only starting to be realised. However, quantitative accuracy of PET relies on accurate attenuation correction (AC) of, not only the patient anatomy but also MRI hardware and current methods, which are prone to artefacts caused by dense materials. Quantitative accuracy of PET also relies on full characterization of patient motion during the scan. The simultaneity of PET-MRI makes it especially suited for motion correction. However, quality assurance …

Optimizing Respiratory Gated Intensity Modulated Radiation Therapy Planning And Delivery Of Early-Stage Non-Small Cell Lung Cancer, Ilma Xhaferllari

Electronic Thesis and Dissertation Repository

Stereotactic ablative body radiotherapy (SABR) is the standard of care for inoperable early-stage non-small cell lung cancer (NSCLC) patients. However, thoracic tumours are susceptible to respiratory motion and, if unaccounted for, can potentially lead to dosimetric uncertainties. Respiratory gating is one method that limits treatment delivery to portions of the respiratory cycle, but when combined with intensity-modulated radiotherapy (IMRT), requires rigorous verification. The goal of this thesis is to optimize respiratory gated IMRT treatment planning and develop image-guided strategies to verify the dose delivery for future early-stage NSCLC patients.

Retrospective treatment plans were generated for various IMRT delivery techniques, including …

Development Of A Small Animal Conformal Irradiator With Dual Energy X-Ray Computed Tomography Imaging For Kilovoltage Dosimetry, Michael D. Jensen

Electronic Thesis and Dissertation Repository

External beam radiotherapy has become technically sophisticated with image guided radiation therapy (IGRT) and intensity modulated radiation therapy (IMRT). These technologies allow for precise delivery of radiation to geometric targets in cancer patients. However, many questions remain on how to best define targets based on biological information, such as functional imaging, and how to combine radiation with other cancer therapies. To help answer these questions, small animal preclinical studies are needed to generate data to inform clinical trials. However, the precise radiation delivery capabilities of IGRT and IMRT have not been available in the preclinical labs. To enable translational experiments …

Mri Relaxation Rates: A Quantitative Approach To Track Tumour Cells Expressing Maga, Anindita Sengupta

Electronic Thesis and Dissertation Repository

Using magnetic resonance imaging, relaxation rate measurements were

performed in cancer cells overexpressing a magnetotactic bacterial gene, MagA.

Measurements of magnetic resonance relaxation rates in this expression

system is important for optimizing cell detection and specificity, for developing

quantification methods, and for refinement of gene-based iron contrast using

magnetosome associated genes. We measured the total transverse

relaxation rate (R2^*), its irreversible and reversible components (R2 and R2^′,

respectively) and the longitudinal relaxation rate (R1) in MDA-MB-435 tumor cells.

Clonal lines overexpressing MagA were cultured in the presence and absence of

iron supplementation, and mounted in a …

Multiparametric Imaging And Mr Image Texture Analysis In Brain Tumors, Harish A. Sharma

Electronic Thesis and Dissertation Repository

Discrimination of tumor from radiation injured (RI) tissues and differentiation of tumor types using noninvasive imaging is essential for guiding surgical and radiotherapy treatments are some of the challenges that clinicians face in the course of treatment of brain tumors. The first objective in this thesis was to develop a method to discriminate between glioblastoma tumor recurrences and radiation injury using multiparametric characterization of the tissue incorporating conventional magnetic resonance imaging signal intensities and diffusion tensor imaging parameters. Our results show significant correlations in the RI that was missing in the tumor regions. These correlations may aid in differentiating between …

The Impact Of Lateral Electron Disequilibrium On Stereotactic Body Radiation Therapy Of Lung Cancer, Brandon Disher

Electronic Thesis and Dissertation Repository

Stereotactic Body Radiation Therapy (SBRT) is an effective treatment option for patients with inoperable early-stage lung cancer. SBRT uses online image-guidance technology [e.g. cone-beam CT (CBCT)] to focus small-fields of high energy x-rays onto a tumour to deliver ablative levels of radiation dose (e.g. 54 Gy) in a few treatment fractions (e.g. 3). For the combination of these treatment parameters and a low density lung, lateral electron disequilibrium (LED) can potentially occur, reducing lung and tumour doses. The goal of this thesis was to determine the impact of LED on stereotactic body radiation therapy for lung cancer.

The effect of …

Metastatic Disease: Interactions Between Tumor Cells And Host Environment During Cancer Cell Spread, Jennifer M. Maclean

Electronic Thesis and Dissertation Repository

Tumor and metastasis formation are not cell autonomous phenomena, but rather an evolution of disease within and responding to the host environment. Metastatic spread from a primary tumor occurs as a result of a complex interplay between tumor cells and the host, wherein tumor cells must escape the primary tumor, enter the host vasculature, travel to and arrest in a distant tissue and survive and grow in that new organ. It is known that cells that progress through these stages must both escape and exploit host systems, yet the mechanisms used are not fully understood. Therefore, the goal of this …

From Isolated Tumour Cells To Overt Lymph Node Metastases: Biological And Imaging Studies On The Development Of Experimental Lymph Node Metastases, Michael M. Lizardo

Electronic Thesis and Dissertation Repository

Metastatic colonization and establishment of overt lymph node (LN) tumours indicates poor prognosis for cancer patients. However, the basic biology that influences the development of LN metastasis is poorly understood due to the lack of basic animal models. The following work provides a new lymph node experimental metastasis assay (LEMA) that permits the assessment of tumour cell fate after they arrest in draining LNs. In using this new model, we discovered that only 8% of the tumour cells that arrive in the LN are successful in forming overt tumours. This work also explored the use of imaging approaches to monitor …