Fluorescence based spectroscopy and imaging techniques provide qualitative and quantitative diagnostic information about biological systems. Some tissue cells have inherent fluorescence characteristics, and when excited with light at a certain frequency, they can emit light of a slightly longer wavelength; a phenomenon known as autofluorescence. Differences in the autofluorescence emission spectra between healthy and diseased tissue may be used as a non-invasive diagnostic tool for the detection of diseases. In this thesis, I describe the design, fabrication, and testing of a miniaturized fluorescence imaging device for non-invasive clinical diagnosis in the gastrointestinal tract. The device is designed such that it can be turned completely wireless. The system includes three sub-modules: optical imaging, electronics control and image acquisition, and information processing and transmission. These modules were individually developed and tested before being integrated into a complete, externally powered device. The final integrated system is small in size (diameter: ~ 2.5 cm; length: ~ 11 cm). The performance of each individual module and the overall integrated system has been evaluated using fluorescent phantoms. It has been demonstrated that the miniaturized device can acquire spectrally-resolved fluorescence images. It has also been separately demonstrated that the image stream can be transmitted wirelessly. An important outcome of this feasibility study is the identification of important technological issues and pathways for future prototype development. / Thesis / Master of Applied Science (MASc)

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

Sheep scab is a highly contagious ectoparasitic disease caused by the mite, Psoroptes ovis, which causes intensely pruritic lesions with severe dermatitis and is a major welfare and production issue in the UK national flock. In an attempt to improve disease control, sheep scab was recently made notifiable in Scotland indicating that early diagnostic tests will be crucial to the success of this legislation. A sensitive and specific antibody based assay has been developed which can diagnose early infestation, but which does not indicate current disease status post-treatment due to residual circulating antibody levels. However, studies into host biology and response to disease have illustrated the potential use of biomarkers (BMs) in diagnostics as indicators of disease progression and the effectiveness of treatment regimes, including a recent microarray analysis which identified over 600 host genes differentially expressed in circulating leukocytes following P. ovis infestation. As many of these genes encoded proteins known to be involved in inflammatory responses, this data was used in the search for potential BMs. Initially the genes were filtered and ranked, using bioinformatic analysis, to identify the most promising BM candidates and then evaluated using Western blot analysis against a range of sera from P. ovis infested and naïve sheep. Promising results were obtained for a complement binding protein, C4BPB, showing it was rapidly up-regulated following infestation and correlated with disease progression as determined by lesion size development. The ovine C4BPB gene was successfully sequenced for the first time and a recombinant form of this protein expressed in E. coli. Antibodies, raised in rabbits against ovine rC4BPB, were used to develop a sandwich ELISA, results from which suggested the potential of C4BPB as a BM for sheep scab as it indicated current disease status postinfestation and post-treatment. The major ruminant acute phase proteins (APPs) serum amyloid A (SAA) and haptoglobin (Hp) were then investigated using commercially available assays, as previous studies indicated they were effective markers of inflammatory disease in ruminants. Results from these analyses indicated that both APPs responded positively to infestation with P. ovis but this was not statistically significant until 4 weeks post-infestation. After treatment, the APPs declined rapidly, as described by their short half life of less than 3 days following successful treatment, compared with 56 days for the estimated half life of the host antibody against the mite antigen Pso o 2. Further statistical analysis of the APP response suggested that SAA was the more discriminatory marker, with lower pre-infestation levels and higher sensitivity at the estimated optimum cut-off values. The possibility of using a signature of BMs, as an alternative to a single BM, was discussed as a method of increasing the sensitivity and specificity of the improved test, along with the potential of combining the BM diagnostic with the existing antibody assay. It was concluded that this would provide a highly sensitive and specific test for sheep scab which would diagnose early infestation as well as indicating current disease status post-treatment, providing a highly beneficial tool to the sheep industry to aid the control of this disease.

In computed radiography (CR) images, dose reduction up to 0.10 mGy is possible in chest radiography without image manipulation.  A lower dose of 0.06 mGy can be achieved when image manipulation is used for detection of lesions in the mediastinum.  Both clarity and detectability in the mediastinum improved by between 48 to 66% with image manipulation.  Abdominal images showed a significant difference at 2.69 mGy for the soft tissue area, suggesting caution in further dose reduction.  Image quality in the spinal area was improved significantly by 21 – 78.6% (for clarity) and 3 to 77% (for detectability) when image manipulation was employed. Comparatively, the image quality at the low doses studied was better for the film screen radiography than both processed and unprocessed CR images suggesting that low doses achieved in FSR may not be applicable to CR.  This difference may be attributed to the differences in the image receptors’ response to high photon energies, and the reduced number of x-ray quanta which produce lower subject contrast in FSR and reduced signal to noise ratio (SNR) as a result of increased noise in CR. Nigerian clay in its natural and salted forms cannot be used in radiation dosimetry in diagnostic radiology.  Paraffin wax/MgSO₄.6H₂0, and rice-gelatine (<i>rigel</i>) combinations as well as rice and gelatine used separately, have shown tissue equivalent x-ray attenuation at tube potentials above 80 kVp.  Paraffin wax/MgSO₄.6H₂0 and <i>rigel </i>can therefore be used as tissue substitutes.  Low patient entrance surface doses achieved in FSR may not produce equivalent image quality when applied to imaging with CR systems.  With respect to dose reduction, both modalities show the possibility of further dose reduction below current dose values by about 40% (chest) and 20% (abdomen), respectively, when used alone.