PATRICIA BERINGHS RIO
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Artigo IPEN-doc 30343 Radiosurgery dosimetry using CaSO4:Eu OSLD film2023 - GASPARIAN, PATRICIA B.R.; MALTHEZ, ANNA L.M.C.; TORQUATO, MICHELE; CAMPOS, LETICIA L.Recent studies demonstrated that optically stimulated luminescence (OSL) systems allow the evaluation of doses for 2D mapping in a relatively fast and simple way and results show submillimeter resolution. This work presents, for the first time, an optically stimulated luminescence dosemeter (OSLD) in the form of film made with CaSO4:Eu particles embedded in a silicone elastomer matrix. The OSLD film was produced using a low-cost and relatively simple methodology. This film is reusable and the signal can be satisfactorily bleached using blue LEDs. The main dosimetric properties were evaluated using TL/OSL Risø reader with blue stimulation and Hoya U-340 filter. Investigation shows repeatability within 3% when measuring with the same film sample. Regarding the OSLD film homogeneity, nearly 12% sensitivity change was observed within the 5 × 5 cm2 produced film. Additionally, the dose response curve shows linearity from 5 to 25 Gy. Fading of the OSL signal is relatively high, about 50% in the first week and then is stable. Nevertheless, a 3 × 3 cm2 OSLD film was successfully used to map dose distribution in radiosurgery (6 MV photon beam). This work demonstrates the feasibility of 2D dosimetry using reusable OSLD films based on CaSO4:Eu.Artigo IPEN-doc 29845 An overview study on the TL and OSL dosimetry patent processes over time2023 - GASPARIAN, P.B.R.; MALTHEZ, A.L.M.C.; MARIANO, L.; CAMPOS, L.L.; POLITANO, R.Since its discovery, ionizing radiation has been used in many different applications. Materials and methods have been developed to measure and quantify radiation doses. Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) are two techniques used for radiation dosimetry. Both TL and OSL are primarily applied in several areas, such as dating of ancient materials, equipment quality control and individual monitoring. One of the parameters to measure the knowledge and development of a technology is the number of patents related to the field. In this work, we established a methodology for patent search on the World Intellectual Property Organization (WIPO) database aiming to review the development of TL and OSL dosimetry over time. We concluded that along with the OSL technique development, the TL technique should continue to be explored in radiation dosimetry.Artigo IPEN-doc 28844 Study of the dosimetric properties of CaSO4:Dy using OSL technique2022 - GASPARIAN, P.B.R.; MALTHEZ, A.L.M.C.; YOSHIMURA, E.M.; UMISEDO, N.K.; CAMPOS, L.L.Calcium sulfate doped with dysprosium (CaSO4:Dy) has been used for personal dosimetry using the thermoluminescence (TL) technique for decades and its TL properties are well-known. Considering the advantages of the OSL technique (relatively simple and faster readout and detector reusability) and the potential application of CaSO4:Dy as an OSL detector, this study aimed to investigate the dosimetric properties of CaSO4:Dy using the OSL technique. The present study was carried out using CaSO4:Dy pellets prepared at IPEN irradiated and read in a TL/OSL Risø reader with blue light stimulation and Hoya U-340 filter. OSL dosimetric properties essentially dose response, reproducibility, and fading characteristics were evaluated. Moreover, TL and OSL signals were compared to study the correlation between OSL signals and TL peaks. CaSO4:Dy OSL response is linear from 0.1 to 10 Gy and shows reproducibility better than 5%. The low-temperature TL peak is unstable; however, the OSL signal seems to be associated with higher-temperature peaks.