Theses and Dissertations at Montana State University (MSU)
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Item MEMS 3-dimensional scanner with SU-8 flexures for a handheld confocal microscope(Montana State University - Bozeman, College of Engineering, 2018) Liu, Tianbo; Chairperson, Graduate Committee: David DickensheetsThe conventional method for diagnosing skin cancer is to perform a biopsy followed by pathology. However not only are biopsies invasive and likely to leave permanent scarring, they also sample the body sparsely. Fortunately, a non-invasive method of imaging called confocal laser scanning microscopy has shown great potential to replacing invasive biopsies. Confocal microscopy can use light to achieve high-resolution imaging of cells that lie underneath the surface of the skin. However, the large size of current confocal microscopes limits their application to all but the most accessible sites. In this dissertation, I address the miniaturization of confocal microscopy through the development of a new microelectromechanical systems scan mirror that can scan a focused beam in three dimensions. The scanner has a 4 mm aperture, and has the capability to replace all of the bulky beam scanners and focus mechanisms that contribute to the large size of current confocal microscopes. The fabrication of the scanner explores the use of the polymer SU-8 for its mechanical structures. The gimbal mirror has demonstrated scan angles in excess of plus or minus 3° mechanical for lateral scanning, and its deformable surface provided controllable deflection up to 10 microns for focus control. This newly developed scanner was integrated into a confocal system to test its imaging capabilities. The device demonstrated high-resolution scanning with simultaneous focus adjustment suitable for the next generation of miniaturized confocal laser scanning microscopes.Item A combined confocal imaging and raman spectroscopy microscope for in vivo skin cancer diagnosis(Montana State University - Bozeman, College of Engineering, 2008) Arrasmith, Christopher Lyman; Chairperson, Graduate Committee: David L. DickensheetsConfocal microscopy has provided a useful tool for imaging biopsied tissue samples. The cross sectioning ability inherent in confocal microscopes provides a method for viewing of cellular structure at different layers of a histology sample, allowing for optical cross sectioning and viewing structures below the surface of the sample. As a cancer diagnosis technique, confocal microscopy has been shown to provide valuable information showing differences in cell morphology of malignant and benign regions. Raman spectroscopy has also been shown to be a useful tool for cancer diagnosis in skin tissues due to its ability to distinguish different types of chemical bonds. While both of these methods may be used for cancer detection, current devices are limited to ex vivo samples. The goal of this project was to design and build a hand held microscope which could be used for in vivo confocal imaging and Raman spectroscopy of suspected malignant lesions in skin. This thesis describes the optical, mechanical and electrical design and fabrication of the microscope, as well as performance testing and initial in vivo skin data collected with the microscope. It is our hope that this instrument will be used to gather important in vivo skin cancer data and spur future developments in small diagnosis tools that can be used in a clinical setting.