Browsing by Author "Ferreira, Sara"
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- PET/CT in the evaluation of hypoxia for radiotherapy planning in head and neck tumors: systematic literature reviewPublication . Lopes, Susana Isabel; Ferreira, Sara; Caetano, MarcoIntroduction: PET/CT combines the molecular with the anatomical level which, with the administration of a hypoxia-sensitive radiopharmaceutical, allows the evaluation of tissue oxygenation. Materials and Methods: The work consists of a systematic literature review, including electronic addresses, books, and articles dating from July 1997 to December 2019. The aim of this work is to identify the best-suited PET radiopharmaceuticals for the detection of cell hypoxia and recognize the benefits for treatment planning with IMRT/VMAT techniques. Results: Hypoxia affects the likelihood of cure of head and neck tumors, thereby reducing the success rate. Radiopharmaceuticals such as 18F-FMISO, 18F-FETNIM, and 18F-HX4 allow the delineation of hypoxic subvolumes within the target volume to optimize IMRT/VMAT treatment. Discussion: The identification of hypoxia areas with PET/CT imaging and subsequent treatment with IMRT/VMAT allows a possible radiation dose escalation in radioresistant subvolumes. Conclusion: There is a decrease in relapses and an increased likelihood of disease-free survival.
- Radiotherapy setup displacements in breast cancer patients: 3D surface imaging experiencePublication . Sá, Ana Cravo; Fermento, Ana; Neves, Dalila; Ferreira, Sara; Silva, Teresa; Coelho, Carina Marques; Vaandering, Aude; Roma, Ana; Quaresma, Sérgio; Bonnarens, EmmanuelAim - In this study, we intend to compare two different setup procedures for female breast cancer patients. Background - Imaging in radiotherapy provides a precise localization of a tumour, increasing the accuracy of the treatment delivery in breast cancer. Materials and methods - Twenty breast cancer patients who underwent whole breast radiotherapy (WBRT) were selected for this study. Patients were divided into two groups of ten. Group one (G1) was positioned by tattoos and then the patient positioning was adjusted with the aid of AlignRT (Vision RT, London, UK). In group two (G2), patients were positioned only by tattoos. For both groups, the first 15 fractions were analyzed, a daily kilovoltage (kV) cone beam computed tomography (CBCT) image was made and then the rotational and translational displacements and, posteriorly, the systematic (Σ) and random (σ) errors were analyzed. Results - The comparison of CBCT displacements for the two groups showed a statistically significant difference in the translational left-right (LR) direction (ρ = 0.03), considering that the procedure with AlignRT system has smaller lateral displacements. The results of systematic (Σ) and random (σ) errors showed that for translational displacements the group positioned only by tattoos (G2) demonstrated higher values of errors when compared with the group positioned with the aid of AlignRT (G1). Conclusions - AlignRT could help the positioning of breast cancer patients; however, it should be used with another imaging method.