Browsing by Author "Khouri, Leila"
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- Analyses of pharyngeal constrictor muscles doses in radiotherapy of head and neck cancer patientsPublication . Guerra, Jéssica; Khouri, Leila; Ferreira, BrigidaLate dysphagia is a radiotherapy (RT) side-effect that may develop up to 3 years after treatment and could be related to the irradiation of the Pharyngeal Constrictor Muscles (PCM) in RT. To quantify the radiation dose delivered to the PCM in head and neck (H&N) cancer patients with and without dysphagia.
- Analysis of the cochlear dose in head and neck cancer radiotherapyPublication . Afonso, Jennifer; Khouri, Leila; Ferreira, BrigidaInternal hearing damage induced by radiotherapy (RT) can lead to sensorineural hearing loss (hypoacusia) due tumor’s proximity with the auditory apparatus. Furthermore, the concurrent use of RT with chemotherapy (cisplatin) is known to increase toxicity. To quantify the radiation dose delivered to the (ipsilateral and contralateral) cochlea in head and neck cancer patients with and without hypoacusia.
- Biological dose-escalated definitive radiation therapy in head and neck cancerPublication . Costa Ferreira, Brigida; Sá-Couto, Pedro; Khouri, Leila; Lopes, Maria do CarmoTo compare treatment outcome of patients with head and neck (HN) tumours treated with definitive radiation therapy that, mainly owing to differences in the fractionation scheme used with simultaneous integrated boost techniques, resulted in a different biological dose.
- Clinical validation of a graphical method for radiation therapy plan quality assessmentPublication . Ventura, Tiago; Dias, Joana; Khouri, Leila; Netto, Eduardo; Soares, André; Costa Ferreira, Brigida; Rocha, Humberto; Lopes, Maria do CarmoBackground: This work aims at clinically validating a graphical tool developed for treatment plan assessment, named SPIDERplan, by comparing the plan choices based on its scoring with the radiation oncologists (RO) clinical preferences. Methods: SPIDERplan validation was performed for nasopharynx pathology in two steps. In the first step, three ROs from three Portuguese radiotherapy departments were asked to blindly evaluate and rank the dose distributions of twenty pairs of treatment plans. For plan ranking, the best plan from each pair was selected. For plan evaluation, the qualitative classification of ‘Good’, ‘Admissible with minor deviations’ and ‘Not Admissible’ were assigned to each plan. In the second step, SPIDERplan was applied to the same twenty patient cases. The tool was configured for two sets of structures groups: the local clinical set and the groups of structures suggested in international guidelines for nasopharynx cancer. Group weights, quantifying the importance of each group and incorporated in SPIDERplan, were defined according to RO clinical preferences and determined automatically by applying a mixed linear programming model for implicit elicitation of preferences. Intra- and inter-rater ROs plan selection and evaluation were assessed using Brennan-Prediger kappa coefficient. Results: Two-thirds of the plans were qualitatively evaluated by the ROs as ‘Good’. Concerning intra- and inter-rater variabilities of plan selection, fair agreements were obtained for most of the ROs. For plan evaluation, substantial agreements were verified in most cases. The choice of the best plan made by SPIDERplan was identical for all sets of groups and, in most cases, agreed with RO plan selection. Differences between RO choice and SPIDERplan analysis only occurred in cases for which the score differences between the plans was very low. A score difference threshold of 0.005 was defined as the value below which two plans are considered of equivalent quality. Conclusion: Generally, SPIDERplan response successfully reproduced the ROs plan selection. SPIDERplan assessment performance can represent clinical preferences based either on manual or automatic group weight assignment. For nasopharynx cases, SPIDERplan was robust in terms of the definitions of structure groups, being able to support different configurations without losing accuracy.
- Estratégia preventiva da mucosite oral em doentes com tumores de cabeça e pescoço. Experiência com fosfato de cálcioPublication . Mousinho, Filipa; Costa Ferreira, Brigida; Khouri, Leila; Guardado, Maria João; Vale Marques, Rui; Rodrigues, Joana M.C.; Melo, GilbertoA mucosite oral é uma consequência frequente no tratamento de doentes oncológicos, nomeadamente de cabeça e pescoço. Refere-se a lesões eritematosas e ulcerativas da mucosa oral em doentes submetidos a radioterapia e/ou quimioterapia. Estas lesões são muitas vezes dolorosas e podem comprometer a nutrição, a hidratação, a higiene oral e ainda aumentar o risco de infecção sistémica. Infecções associadas a mucosite oral podem ser a causa de sepsis em doentes imunodeprimidos.
- Semi-supervised Self-training Approaches in Small and Unbalanced Datasets: Application to Xerostomia Radiation Side-EffectPublication . Soares, Inês; Dias, Joana; Rocha, Humberto; Khouri, Leila; Lopes, Maria do Carmo; Costa Ferreira, BrigidaSupervised learning algorithms have been widely used as predictors and applied in a myriad of studies. The accuracy of the classification algorithms is strongly dependent on the existence of large and balanced training sets. The existence of a reduced number of labeled data can deeply affect the use of supervised approaches. In these cases, semi-supervised learning algorithms can be a way to circumvent the problem.
- SPIDERplan: A tool to support decision-making in radiation therapy treatment plan assessmentPublication . Ventura, Tiago; Lopes, Maria do Carmo; Costa Ferreira, Brigida; Khouri, LeilaAim In this work, a graphical method for radiotherapy treatment plan assessment and comparison, named SPIDERplan, is proposed. It aims to support plan approval allowing independent and consistent comparisons of different treatment techniques, algorithms or treatment planning systems. Background Optimized plans from modern radiotherapy are not easy to evaluate and compare because of their inherent multicriterial nature. The clinical decision on the best treatment plan is mostly based on subjective options. Materials and methods SPIDERplan combines a graphical analysis with a scoring index. Customized radar plots based on the categorization of structures into groups and on the determination of individual structures scores are generated. To each group and structure, an angular amplitude is assigned expressing the clinical importance defined by the radiation oncologist. Completing the graphical evaluation, a global plan score, based on the structures score and their clinical weights, is determined. After a necessary clinical validation of the group weights, SPIDERplan efficacy, to compare and rank different plans, was tested through a planning exercise where plans had been generated for a nasal cavity case using different treatment planning systems. Results SPIDERplan method was applied to the dose metrics achieved by the nasal cavity test plans. The generated diagrams and scores successfully ranked the plans according to the prescribed dose objectives and constraints and the radiation oncologist priorities, after a necessary clinical validation process. Conclusions SPIDERplan enables a fast and consistent evaluation of plan quality considering all targets and organs at risk.