| dc.description.abstract | The aim of this thesis was to investigate both the survival of mouse oral carcinoma (MOC2) cells following x- ray irradiation and production of micronuclei following both x-ray and proton irradiation MOC2 and A549 lung cancer cells. The project consisted of experimental work in addition to program development for image analysis. The first part of the project considered the survival of x-ray irradiated MOC2 cells. A survival curve based on the linear quadratic (LQ) model was established by clonogenic assay experiments. The parameters of the LQ model were determined by linear regression and an 𝛼-value of 𝛼 = 0.1693 and a 𝛽-value of 𝛽 = 0.0416 were found. The 99% confidence intervals were [0.0965, 0.2421] and [0.0331, 0.0500] for 𝛼 and 𝛽 respectively. By comparing these results to previous survival experiments, MOC2 were found to be less radiosensitive than MOC1 and A549 cells. The second part of the project considered micronucleus production following both x-ray and proton irradiation. An experimental method for observation of micronuclei by using a confocal microscope had previously been established. However, manual scoring turned out to be both labor intensive and inconsistent across different observers. One of the main components of the present project was to establish an automated method for micronucleus scoring based on image analysis. A method using Otsu thresholding and watershed segmentation was developed and used for analysis of experimental data from 6 experiments. The algorithm is sensitive to image quality, in particular background light gradients and low contrast. The causes for the algorithm’s sensitivity were identified, and specific improvements were suggested. The results of the analysis of the experimental data suggest that a higher dose and a higher linear energy transfer (LET) are both associated with an increased micronucleus production for MOC2 and A549 cells following both proton and x-ray irradiation. However, the conclusion was only statistically significant for x-ray irradiated A549 cells and proton irradiated MOC2 cells. Micronucleus production is assumed to contribute to anti-cancer immune responses. Future experiments investigating the underlying mechanisms will require a consistent and stable method for quantifying the micronucleus response. This project has implemented such a method using segmentation-based image analysis. | eng |