À la Une

Soutenance de thèse Arianna Religi

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Mme Arianna Religi soutiendra en anglais, en vue de l'obtention du grade de docteur ès sciences, mention informatique, sa thèse intitulée:

Ground UV Irradiance and 3D Rendering Techniques to Predict Anatomical Solar UV Exposure in Skin Cancer Research and Prevention

Date: Lundi 24 septembre 2018 à 10h00

Lieu: CUI / Battelle bâtiment A, auditoire rez-de-chaussée

Jury:

  • Prof. Stéphane Marchand-Maillet (advisor)
  • Dr. Laurent Moccozet (co-advisor)
  • Prof. Katarzyna Wac (internal examiner)
  • Dr. Caecilia Charbonnier (external examiner)

Résumé:

The solar ultraviolet (UV) radiation is one of the most relevant environmental factors for human health. While small amounts of UV can bear favourable effects and are essential in the production of vitamin D, protracted exposure may cause acute and chronic effects on skin, eyes and immune system. In particular, UV radiation has a significant influence on the premature ageing of the skin and on the development of skin cancers like cutaneous malignant melanoma (CMM), basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Over the past decades, because of the progressive increase in outdoor leisure activities, vacations in sunny regions and change in clothing habits, the incidence of skin cancer has sharply increased in many industrialised countries. On the other hand, studies suggest that upwards of 30–50% of children and adults are at risk of vitamin D deficiency. It is crucial then to estimate effective solar UV radiation needed for the vitamin D production and, at the same time, low enough to decrease sun damage risk.

This research stems from this need, focusing on the existing gaps between the growing burden of both skin cancer and vitamin D deficiency and the tools available to assess and manage UV exposure, gathering competencies in different fields, such as 3D computing science (Centre Universitaire d’Informatique of Geneva), meteorology (MeteoSwiss), public health (Institute of Work and Health of the University of Lausanne) and epidemiology (Cancer Epidemiology Unit of the Centre Hospitalier Universitaire Vaudois).

Since UV exposure is highly heterogeneous and strongly influenced by host and behavioural factors, such as posture, orientation to the sun, skin complexion and clothing, a three-dimensional numeric model (SimUVEx) has been developed to assess the dose and distribution of anatomical UV exposure. The model uses 3D computer graphics techniques to compute UV radiance on the basis of ambient irradiation data without necessitating time-consuming individual dosimetry, ensuring a wide potential use in skin cancer prevention and research. With the purpose to improve simulation capabilities and obtain more realistic scenarios in quantifying effective sun protection strategies, a second version (SimUVEx v2.0) was released and will be illustrated within this thesis, describing the model and its validation analysis.

Various sun protection estimates, both artificial (sunglasses, hats, shade structures) and natural (hair) will be investigated for facial zones, including eyes.

Afterwards, some applications carried out within the project are shown moving from the individual basis and considering the whole Switzerland and some other countries with which we established a collaboration. In particular, our focus lied on: cloud effects on erythemally weighted UV radiation for estimating exposure ratio (in Sweden), estimation of an optimal UV exposure balance between vitamin D and skin damage (in Switzerland), measurements of UV reflection on coastal sand (in Spain) and on the analysis of the dynamic effect on exposure (in Germany). Finally the results of the project will be summarize, underlining some potential applications and an overview of where to go next.

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