En 2006 Dilmanian et al. ont proposé une méthode d'irradiation par rayonnement synchrotron innovante appelée minifaisceaux. L'irradiation de tumeur par minifaisceaux monochromatiques consiste en un motif fractionné spatialement de faisceaux de rayons X submillimétriques produits par un synchrotron. Afin d'obtenir une dose homogène dans le volume cible, deux incidences orthogonales sont entrecroisées. Le tissu sain environnant ne subit que l'irradiation fractionnée, entre les faisceaux la dose n'est dûe qu'au diffusé et l'énergie déposée y est donc 10 à 15 fois inférieure à celle déposée sur les axes des faisceaux. Cela permet un effet protecteur des tissus sains tout en distribuant de fortes doses à la tumeur. Cette thèse porte sur le développement de la méthode expérimentale des minifaisceaux monochromatiques, ce qui comprend le contrôle de la géométrie d'irradiation, la dosimétrie expérimentale et l'étude Monte Carlo correspondante. Afin d'évaluer son efficacité, des études précliniques ont été réalisées sur un modèle de tumeur cérébrale implantée chez le rat (F98). Un suivi de traitement est réalisé par de l'imagerie anatomique et fonctionnelle afin d'évaluer son efficacité. L'imagerie de perfusion cérébrale (menant aux volumes et débits sanguin cérébrales, au temps de transit moyen) est d'après la littérature un moyen efficace de pronostique du résultat du traitement. Les paramètres clés de la vascularisation cérébrale sont principalement étudiés par imagerie IRM, du fait de l'innocuité de ce type d'imagerie. La Synchrotron Radiation Computed Tomography (SRCT) est une modalité d'imagerie dont les performances sont proches des limites théoriques dans l'obtention de mesures absolues des concentrations d'agent de contraste et peut être utilisé en tant que gold-standard. Les modèles pharmacocinétiques utilisés nécessitent comme paramètre d'entrée des concentrations d'agent de contraste en fonction du temps. La relation entre le signal obtenu par IRM et la concentration d'agent de contraste est très complexe et difficilement quantitative. Une comparaison des mesures de perfusion effectuées par IRM et par SRCT a été effectuée afin de calibrer les mesures IRM. / An innovative method of synchrotron radiation therapy, called minibeams, was proposed by A. Dilmanian et al. in 2006. Minibeams consists in tumor irradiation with monochromatic submillimetric x-ray beams spatially fractionated produced by a synchrotron source. To obtain a homogeneous dose in the target volume, an interleaving is realized using two orthogonal incidences. Adjacent healthy tissue is only partially irradiated by minibeams, the areas between the beams only receive scattered radiation and therefore the energy deposited is 10 to 15 times lower than on one minibeam axis, leading to a sparing effect of healthy tissue even when a high dose is deposited in the target volume. The thesis project is the development of this experimental method of monochromatic minibeams, which involves the control of the irradiation geometry, the control of dosimetry and its modeling by Monte Carlo simulations. To evaluate the method, preclinical experiments on models of brain tumors implanted in rats (F98) are performed. Follow-up by anatomical and functional imaging is carried out to evaluate the effectiveness of the treatment. Functional imaging of cerebral perfusion (volume and cerebral blood flow, mean transit time of heavy elements) appears to be associated in the literature as a relevant method for monitoring prognostic. The key parameters of the cerebral vasculature are mainly studied in magnetic resonance imaging (MRI), because of the harmlessness of this imaging modality. The relation between MRI signal and contrast agent concentration is very complex and no quantitative relationship is well known. Synchrotron Radiation Computed Tomography (SRCT) is an imaging modality with performances to measure absolute contrast agent concentration very close to the theoretical limits and can be used as gold-standard. The used pharmacokinetic models need as input parameters a contrast agent concentration versus time. A comparison of perfusion measurements between MRI and SRCT has been done in order to calibrate MRI measurements.

The aim of the study is to determine the nature and utilisation of an Employee Assistance Programme (EAP) in a white-collar work environment, and, more specifically, in a South African context. Information about the research topic was obtained from accumulate records of the Standard Bank's Employee Well-being Programme (EWP), structured interviews which were conducted with eleven EWP practitioners and a union representative, and from self-administered questionnaires which were completed by a sample of 153 of the bank's employees. The study includes an in-depth literature review on EAPs in general and issues such as the nature and scope of the bank's EWP, the extent to which the EWP addresses employees' needs, the nature and extent of the marketing of the EWP, and the extent to which the workforce is utilising the programme, were explored and described. The main findings are that the EWP shows evidence of acceptance by employees as well as a degree of utilisation that compares favourably with local and international trends. It also shows an incongruence between marketing and employee orientation and training initiatives and reveals that programme evaluation efforts are insufficient and could be significantly improved. Accordingly, recommendations have been made pertaining to the needs of employees, employee and union involvement, a multi-disciplinary approach to case management, marketing, training and evaluation with regard to the EWP, an EWP database, and a post-treatment follow-up. / Social Work / M.A. (Social Work)

The aim of the study is to determine the nature and utilisation of an Employee Assistance Programme (EAP) in a white-collar work environment, and, more specifically, in a South African context. Information about the research topic was obtained from accumulate records of the Standard Bank's Employee Well-being Programme (EWP), structured interviews which were conducted with eleven EWP practitioners and a union representative, and from self-administered questionnaires which were completed by a sample of 153 of the bank's employees. The study includes an in-depth literature review on EAPs in general and issues such as the nature and scope of the bank's EWP, the extent to which the EWP addresses employees' needs, the nature and extent of the marketing of the EWP, and the extent to which the workforce is utilising the programme, were explored and described. The main findings are that the EWP shows evidence of acceptance by employees as well as a degree of utilisation that compares favourably with local and international trends. It also shows an incongruence between marketing and employee orientation and training initiatives and reveals that programme evaluation efforts are insufficient and could be significantly improved. Accordingly, recommendations have been made pertaining to the needs of employees, employee and union involvement, a multi-disciplinary approach to case management, marketing, training and evaluation with regard to the EWP, an EWP database, and a post-treatment follow-up. / Social Work / M.A. (Social Work)

Objective: Recent evidence suggests that illness perceptions in paediatric patients and their parents may differ, with parents holding more negative views compared to their children. Little is known about illness perceptions of very young patients and their parents. This study investigates illness perceptions in paediatric cancer patients aged 4–18 years and their parents in acute treatment or follow‐up care, distinguishing patients by age (4–11, 12–18) and stage of medical treatment. - Methods: N = 45 patient–parent dyads in acute treatment and n = 95 dyads in follow‐up care were examined. Parents and older children aged 12–18 years completed the Illness Perception Questionnaire—Revised (IPQ‐R) and younger children aged 4–11 years were examined using an age‐adapted hand puppet interview containing the IPQ‐R questions. Difference scores of illness perceptions (symptoms, timeline‐acute/chronic, timeline‐cyclical, personal control, illness coherence, consequences, emotional representations) between children and parents were tested for significance using Wilcoxon signed‐rank tests. - Results: Overall, parents perceived more symptoms associated with their child's illness/treatment than the children themselves. In acute treatment, younger children indicated more negative and older children more positive views regarding chronicity than parents. Younger children held less negative views on consequences, and all children reported less negative emotional representations than parents. In follow‐up care, all children held less negative views on consequences and emotional representations. Older children reported less negative views on chronicity, cyclicity and illness coherence. - Conclusion: Differences in illness perceptions of paediatric patients and their parents should be considered during and after treatment/medication and psychosocial care to support illness coping in person‐ and family‐centred interventions.