DANIELA PIAI GROPPO
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Tese IPEN-doc 28012 Correlação de parâmetros físicos e dosimétricos de diferentes detectores utilizados em dosimetria de campos pequenos para radioterapia em um acelerador linear clínico2020 - GROPPO, DANIELA P.Atualmente, as doses administradas em procedimentos radiocirúrgicos são extremamente elevadas, quando comparadas a outros procedimentos radioterápicos. A acurácia dosimétrica para esses tipos de tratamentos requer um comissionamento de campos pequenos de radiação a serem parametrizados em um sistema de planejamento computadorizado. A medição dosimétrica (relativa e direta) de campos pequenos representa um desafio, pois pode introduzir erros na entrega de dose; assim, alguns parâmetros dosimétricos (perfil de dose e porcentagem de dose na profundidade) da interação da radiação com a matéria podem ser comprometidos como o equilíbrio de partículas carregadas. Para melhor mensurar esses dados dosimétricos, alguns detectores são empregados. Mesmo com o uso destes detectores específicos, faz-se necessário identificar e avaliar as incertezas que podem provir do efeito do tamanho do volume e do arranjo experimental do detector sob o campo de radiação. Neste trabalho, as medições dosimétricas foram obtidas com filmes radiocrômicos (medição de referência), câmaras de ionização de volume sensível pequeno, diodos e detectore de diamante. Para correlacionar os parâmetros físicos e dosimétricos obtidos com os detectores, foram utilizados formalismos matemáticos. Esses formalismos matemáticos propostos mostraram-se eficazes quando aplicados à dosimetria de campos pequenos circulares em aceleradores lineares clínicos da fabricante Elekta, modelo Versa HD®, com feixes de fótons (6 MV), com e sem o uso do filtro aplainador (flattening filter).Artigo IPEN-doc 27205 Determination of the penumbra width of Elekta SRS cone collimator for 6 MV FF and 6 MV FFF energies using gradient-based edge detection2020 - GROPPO, DANIELA P.; SARAIVA, CRYSTIAN W.C.; CALDAS, LINDA V.E.The dosimetric measurements of small fields of radiation are undertaken with detectors such as: GafchromicTM films, diodes, diamond detectors and ionization chambers of small volumes. The penumbra width, e.g. the spatial distance between 80% and 20% dose, is smaller in small fields. This fact increases the curvature and hence the volume effect in the penumbra region. The accuracy in the penumbra calculation is important at the QA test for implementation of the cranial Stereotactic Radiosurgery. The objective of this work was to apply a Gradient- Based Edge Detection plugin to calculate the penumbra of a radiation beam defined with the Elekta SRS Cone Collimators for beams of 6 MV (Flattening Filter – FF) and 6 MV (Flattening Filter Free – FFF) energies using the beam profile obtained with GafchromicTM film. The results corroborate those from the literature, and they allow a quantitative evaluation of the width of dosimetric penumbra by Gradient-Based Edge Detection.Artigo IPEN-doc 26872 Gamma Knife radiosurgery for vestibular schwannomas2020 - SARAIVA, CRYSTIAN W.C.; CARDOSO, SIMONE C.; GROPPO, DANIELA P.; SALLES, ANTONIO A.F. de; AVILA, LUIZ F. de; ROSA, LUIZ A.R. daIntroduction This study explores the possibility of a relationship between the sphericity degree of a target volume with the dose distribution. This relationship is evaluated based on the ratio isodose volume / target volume (IV/TV) and the metrics coverage, i.e., selectivity, gradient index, conformity index and mean dose when planning radiosurgery for vestibular schwannoma. Methods Sphericity degree (φ) was calculated for each target volume (TV) of 64 patients who underwent stereotactic radiosurgery (SRS) for vestibular schwannoma. The calculation of this parameter was developed using the theoretical definition for operational sphericity φ = VP/ VCS. The values found are evaluated considering the following metrics:—Coverage (C), selectivity (S), gradient index (GI), Paddick conformity index (CIPaddick) and dose distribution (IV/TV). The planning was also carried out considering a spherical target volume defined in a spherical phantom. The spherical volume is the same as the target used in the treatment plan. The planning of the spherical target was considered as a reference plan to evaluate the dose distribution inside and outside the volume. Results It was possible to observe that the majority of target volumes has (ϕ) around 0,66–0,77, corresponding to 54,7% of the total. Considering the mean values for metrics, the results are: C = 0,98, S = 0,78, GI = 3,11 and CI = 0,81. The dose distribution was equivalent for treatment plans and reference plans. Quantitative analysis for IV/TV shows that these values are higher than 30% for treatment plans where shot density is large. Conclusion This study demonstrates that de sphericity degree (φ) can be related to the dose distribution (IV/TV). Therefore the sphericity degree is a good parameter to evaluate the dose distribution of a plan for vestibular schwannoma treatment, considering the reference plan as being a spherical target using a leksell gamma knife® perfexion (LGKP). This study shows that the sphericity degree offers important information of the dose distribution outside and inside the target volume. This is not evaluated by the other parameters already implemented as metric to analyzing the GKP plans.Resumo IPEN-doc 26026 Determination of the penumbra width of Elekta SRS Cone Collimator for 6 MV FF and 6 MV FFF energies using Gradient-Based Edge Detection2018 - GROPPO, DANIELA P.; SARAIVA, CRYSTIAN W.C.; CALDAS, LINDA V.E.Artigo IPEN-doc 23571 OSL response bleaching of BeO samples, using fluorescent light and blue LEDs2016 - GROPPO, DANIELA P.; CALDAS, LINDA V.E.The optically stimulated luminescence (OSL) is widely used as a dosimetric technique for many applications. In this work, the OSL response bleaching of BeO samples was studied. The samples were irradiated using a beta radiation source (90Sr+90Y); the bleaching treatments (fluorescent light and blue LEDs) were performed, and the results were compared. Various optical treatment time intervals were tested until reaching the complete bleaching of the OSL response. The best combination of the time interval and bleaching type was analyzed.Artigo IPEN-doc 21503 OSL response bleaching of BeO samples, using fluorescent light and blue LEDs2015 - GROPPO, DANIELA P.; CALDAS, LINDA V.E.Artigo IPEN-doc 20191 Luminescent response from BeO exposed to alpha, beta and X radiations2014 - GROPPO, D.P.; CALDAS, L.V.E.Resumo IPEN-doc 17495 Resultados preliminares de um sistema TL Vinten 802 para monitoração individual2011 - GROPPO, DANIELA P.; CALDAS, LINDA V.E.Resumo IPEN-doc 18627 Dosimetric characterization of BeO OSL detectors in standard X radiation beams2012 - GROPPO, DANIELA P.; CALDAS, LINDA V.E.Resumo IPEN-doc 19774 Luminescent response from BeO exposed to alpha, beta and X radiations2013 - GROPPO, DANIELA P.; CALDAS, LINDA V.E.