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Full-Text Articles in Medicine and Health Sciences

Strategies For Reducing The Impact Of Tumour Motion During Helical Tomotherapy, Bryan Kim Aug 2011

Strategies For Reducing The Impact Of Tumour Motion During Helical Tomotherapy, Bryan Kim

Electronic Thesis and Dissertation Repository

Tumour motion presents a significant limitation for effective radiotherapy of lung cancer, and more specifically for helical tomotherapy. The simultaneous and continuous movements of tomotherapy subsystems (gantry, couch, and binary multi-leaf collimator) can lead to inaccurate dose delivery, when combined with tumour motion. In this thesis, we have investigated the impact of tumour motion and strategies to reduce the resulting dose discrepancies for helical tomotherapy, through computer simulations and film measurements performed in a dynamic body phantom. Three distinctively different types of dose discrepancies have been isolated: dose rounding, dose rippling, and the intensity-modulated radiation therapy (IMRT) asynchronization effect. Each …


Metastatic Disease: Interactions Between Tumor Cells And Host Environment During Cancer Cell Spread, Jennifer M. Maclean Jul 2011

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 Apr 2011

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 …


The Characteristics Of Successful Evidence Retrieval By Nephrologists And The Impact Of Pubmed Search Filters, Salimah Shariff Mar 2011

The Characteristics Of Successful Evidence Retrieval By Nephrologists And The Impact Of Pubmed Search Filters, Salimah Shariff

Electronic Thesis and Dissertation Repository

Background: Clinicians frequently search PubMed to guide patient care. This study investigated the factors that impact successful searching and the utility of PubMed search filters.

Methods: A random sample of nephrologists was surveyed between 2008 and 2010; 160 valid responses were received (72% response rate). One group of 60 respondents was presented with the same two clinical questions, while the other 100 were each presented with a unique clinical question. The clinical questions were based on recently published systematic reviews. Respondents provided the search terms they would type into PubMed to address their clinical question(s). All physician-provided searches …