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4 results on '"Arous, Delmon"'

1. Principal component-based image segmentation: a new approach to outline in vitro cell colonies

Author

Arous, Delmon, Schrunner, Stefan, Hanson, Ingunn, Edin, Nina F. J., and Malinen, Eirik

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

The in vitro clonogenic assay is a technique to study the ability of a cell to form a colony in a culture dish. By optical imaging, dishes with stained colonies can be scanned and assessed digitally. Identification, segmentation and counting of stained colonies play a vital part in high-throughput screening and quantitative assessment of biological assays. Image processing of such pictured/scanned assays can be affected by image/scan acquisition artifacts like background noise and spatially varying illumination, and contaminants in the suspension medium. Although existing approaches tackle these issues, the segmentation quality requires further improvement, particularly on noisy and low contrast images. In this work, we present an objective and versatile machine learning procedure to amend these issues by characterizing, extracting and segmenting inquired colonies using principal component analysis, k-means clustering and a modified watershed segmentation algorithm. The intention is to automatically identify visible colonies through spatial texture assessment and accordingly discriminate them from background in preparation for successive segmentation. The proposed segmentation algorithm yielded a similar quality as manual counting by human observers. High F1 scores (>0.9) and low root-mean-square errors (around 14%) underlined good agreement with ground truth data. Moreover, it outperformed a recent state-of-the-art method. The methodology will be an important tool in future cancer research applications.

Published
2021
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2. Acute normal tissue responses in a murine model following fractionated irradiation of the head and neck with protons or X-rays

Author

Zlygosteva, Olga, Juvkam, Inga Solgård, Arous, Delmon, Sitarz, Mateusz, Sørensen, Brita Singers, Ankjærgaard, Christina, Andersen, Claus E., Galtung, Hilde Kanli, Søland, Tine Merete, Edin, Nina Jeppesen, Malinen, Eirik, Zlygosteva, Olga, Juvkam, Inga Solgård, Arous, Delmon, Sitarz, Mateusz, Sørensen, Brita Singers, Ankjærgaard, Christina, Andersen, Claus E., Galtung, Hilde Kanli, Søland, Tine Merete, Edin, Nina Jeppesen, and Malinen, Eirik

Abstract

Background: The purpose of this study was to investigate acute normal tissue responses in the head and neck region following proton- or X-irradiation of a murine model. Materials and methods: Female C57BL/6J mice were irradiated with protons (25 or 60 MeV) or X-rays (100 kV). The radiation field covered the oral cavity and the major salivary glands. For protons, two different treatment plans were used, either with the Bragg Peak in the middle of the mouse (BP) or outside the mouse (transmission mode; TM). Delivered physical doses were 41, 45, and 65 Gy given in 6, 7, and 10 fractions for BP, TM, and X-rays, respectively. Alanine dosimetry was used to assess delivered doses. Oral mucositis and dermatitis were scored using CTC v.2.0-based tables. Saliva was collected at baseline, right after end of irradiation, and at day 35. Results: The measured dose distribution for protons (TM) and X-rays was very similar. Oral mucositis appeared earlier, had a higher score and was found in a higher percentage of mice after proton irradiation compared to X-irradiation. Dermatitis, on the other hand, had a similar appearance after protons and X-rays. Compared to controls, saliva production was lower right after termination of proton- and X-irradiation. The BP group demonstrated saliva recovery compared to the TM and X-ray group at day 35. Conclusion: With lower delivered doses, proton irradiation resulted in similar skin reactions and increased oral mucositis compared to X-irradiation. This indicates that the relative biological effectiveness of protons for acute tissue responses in the mouse head and neck is greater than the clinical standard of 1.1. Thus, there is a need for further investigations of the biological effect of protons in normal tissues.

Published
2023

4. A preclinical model to investigate normal tissue damage following fractionated radiotherapy to the head and neck.

Author

Juvkam, Inga Solgård, Zlygosteva, Olga, Arous, Delmon, Galtung, Hilde Kanli, Malinen, Eirik, Søland, Tine Merete, and Edin, Nina Jeppesen

Subjects
ORAL mucosa, ANIMAL models in research, SALIVARY glands, NECK, MONTE Carlo method, RADIODERMATITIS, TISSUES
Abstract

Radiotherapy (RT) of head and neck (H&N) cancer is known to cause both early- and late-occurring toxicities. To better appraise normal tissue responses and their dependence on treatment parameters such as radiation field and type, as well as dose and fractionation scheme, a preclinical model with relevant endpoints is required. 12-week old female C57BL/6 J mice were irradiated with 100 or 180 kV X-rays to total doses ranging from 30 to 85 Gy, given in 10 fractions over 5 days. The radiation field covered the oral cavity, swallowing structures and salivary glands. Monte Carlo simulations were employed to estimate tissue dose distribution. The follow-up period was 35 days, in order to study the early radiation-induced effects. Baseline and post irradiation investigations included macroscopic and microscopic examinations of the skin, lips, salivary glands and oral mucosa. Saliva sampling was performed to assess the salivary gland function following radiation exposure. A dose dependent radiation dermatitis in the skin was observed for doses above 30 Gy. Oral mucositis in the tongue appeared as ulcerations on the ventral surface of the tongue for doses of 75–85 Gy. The irradiated mice showed significantly reduced saliva production compared to controls. In summary, a preclinical model to investigate a broad panel of normal tissue responses following fractionated irradiation of the H&N region was established. The optimal dose to study early radiation-induced effects was found to be around 75 Gy, as this was the highest tolerated dose that gave acute effects similar to that observed in cancer patients. [ABSTRACT FROM AUTHOR]

Published
2023
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