Percorrer por autor "Bravo, Isabel"
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- 3D vs 2D Cell Cultures in the Evaluation of Radiobiological Effects of Exposition to Low Doses - Medical Imaging Levels - of Ionizing RadiationPublication . Costa, Pedro; Caires, Hugo; Lemos, Joana; Cunha, Lídia; Bravo, Joana; Bravo, Isabel; Silva, Regina; Summavielle, Teresa; Metello, Luís F.Pretending to develop advanced biological models to study biological effects of low doses of ionizing radiation and following the actual policies on Animal Sciences, based on 3 R’s Rule (to Reduce, Refine and Replace) – that limits as much as possible the application of animal models – scientific research using cellular models is constantly increasing. Nevertheless, the intrinsic limitations of actual cellular models quite often had been recognized on a significant number of papers pointing a significant number of non-concordances between results obtained using in vitro and in vivo studies. Actually, an increasing number of authors admit that three-dimensional cell culture (and spheroid cell culture in particular) could represent an interesting solution and a step further on use of cellular models. The work here to be presented reflects the first phase on the use of this methodology on the study, evaluation and quantification of cellular effects of low doses – starting on medical imaging level - of exposition to ionizing radiation.
- Integrating PET for tumour hypoxia in radiotherapy planning: Insights from Portuguese radiotherapy and nuclear medicine technologistsPublication . Sousa, Ruben Diogo Oliveira; Faria, Brígida Mónica; Bravo, Isabel; Costa, Pedro; Costa, Pedro; Faria, Brigida MonicaIn the era of personalised medicine, tumour hypoxia (TH) is critical in radiotherapy (RT) response due to its role in tumour resistance. Positron Emission Tomography (PET) enables non-invasive assessment of TH and supports heterogeneous dose-escalation to hypoxic sub-volumes, improving treatment efficacy. This study explores Nuclear Medicine Technologists (NMT) and Radiotherapy Technologists (RTT) perceptions of PET-based TH (PET-TH) assessment and implementation in RT planning in Portugal. We conducted an observational cross-sectional survey of RTTs and NMTs currently working in Portuguese healthcare institutions. Statistical tests were used to assess associations and compare distributions using IBM® SPSS®. A total of 66 participants, 57 (86.4 %) females, with a mean age of 33.68 (±8.13) years, were included: 23 (34.8 %) NMTs and 43 (65.2 %) RTTs. While 65.2 % of NMT departments had PET scans with RT-compatible settings, only 8.7 % had performed PET-TH studies. Among RTTs, 88.4 % reported that their treatment planning systems were compatible with PET/CT fusion, yet only 9.3 % had used PET in RT planning. RTTs received more training in TH (p = 0.006) and rated their knowledge higher than NMTs (p = 0.042). Greater professional experience and higher perceived knowledge were associated with better performance on evaluation items (p = 0.027; p = 0.037). Regardless of institution type, 92.4 % expressed interest in interprofessional collaboration to support individualised planning. The assessed departments possess infrastructures for PET-TH integration, yet clinical implementation remains limited. Knowledge and professional experience are associated with competency. Targeted training for Technologists and interdisciplinary workflows may improve PET-TH adoption. Addressing knowledge and workflow could facilitate PET integration into RT planning and potentially enhance treatment outcomes. Future efforts should focus on interdisciplinary collaboration.
- Study of Non-Targeted Effects Induced on Cell Lines Using Low Doses of Ionizing RadiationPublication . Caires, Hugo R.; Costa, Pedro; Lemos, Joana; Silva, Regina; Bravo, Isabel; Cunha, Lídia; Metello, Luís F.The LNT - Linear-no-Threshold model, used to analyze dose-effect ratios after biological irradiation exposures, theorizes that effects produced are directly proportional to the irradiating doses, with a linear without threshold pattern. Nevertheless, there is a relevant number of evidence, accumulated essentially over the last decade, suggesting that risks inherent to low doses of irradiation cannot be strictly predicted by the LNT model. Among those, there is a significant number of experimental evidence for a variety of low dose induced biological phenomena, which seems to have an impact on modulating the shape of dose-effect curves, namely for expositions below 0.2 Sv, causing the deviation of LNT model. Accumulated evidence demonstrate that cell irradiation induces biological effects, both to directly irradiated cells as well as to cells not exposed to any kind of ionizing radiation, present in a mixed population. This assumption is breaking the classical idea, based on the belief that damage to cellular DNA is only induced by purely ionizing events in cells directly irradiated. This phenomenon, based on cell communication pathways, is termed “Bystander Effect” - clearly highlighted between the “non-targeted effects” of irradiation not considered by the LNT model - being considered one of the biggest paradigm shifts of modern radiobiology.
- Zebrafish and Nuclear Medicine methods and techniques: an each-day improving partnershipPublication . Lemos, Joana; Metello, Luís F.; Caires, Hugo; Costa, Pedro; Martins, Rosario; Bravo, Isabel; Carvalho, António Paulo; Vasconcelos, VítorAims: This work aims the introduction of zebrafish as a very promising and each day more interesting animal model in radiobiology. It will be briefly discussed the most relevant advantages and disadvantages related with the use of zebrafish, mentioning some of the previous studies using this model in Nuclear Medicine and concluding with its potential applications.