Percorrer por autor "Di Maria, Salvatore"
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- Assessment of carrier-free metallacarboranes for targeted radiation therapies PBFT and BNCT : comparative cellular effects and dosimetry studies with [o-FESAN]− in breast cancer cellsPublication . Di Maria, Salvatore; Pinheiro, Teresa; Alves, Luís Cerqueira; Bitonto, Valeria; Protti, Nicoletta; Crich, Simonetta Geninatti; Nishimura, Kai; Nakamura, Hiroyuki; Matos, António P.; Pinto, Catarina I. G.; Mendes, Filipa; Teixidor, Francesc; Viñas, Clara; Marques, FernandaBackground: Ferrabis(dicarbollide) ([o-FESAN]−) in combination with proton–boron fusion therapy (PBFT) or boron neutron capture therapy (BNCT) are promising alternative radiation modalities for the treatment of breast cancer. The aim of this study was to explore the underlying effects of [o-FESAN]− radio enhancement on breast cancer cells in vitro and in vivo, and to perform comparative dosimetry calculations. Methods: The cellular effects on SKBR-3 and MDA-MB-231 breast cancer cells and MDA-MB-231 xenograft-bearing nude mice induced by carrier-free [o-FESAN]− after BNCT or PBFT were evaluated following recommended protocols. Monte Carlo (MC) dosimetry calculations were performed at the cellular scale for both radiation modalities. Results: Selective retention of [o-FESAN]− within the cytoplasm and nucleus of SKBR-3 and MDA-MB-231 breast cancer cells is demonstrated. Moreover, in vivo studies with MDA-MB-231 xenograft-bearing nude mice show appreciable accumulation of [o-FESAN]− in the tumor. Both radiation modalities induce loss of cellular viability and survival. Comparative dosimetry studies between proton and neutron irradiation agree with the viability data, showing a good correlation between absorbed dose vs. cellular effects. In the case of PBFT, cell structural changes are likely due to necrosis caused by the production of reactive oxygen species (ROS). To explain the radio enhancement effects in more detail, other mechanisms should be taken into consideration. Conclusions: Our results validate the effectiveness of both PBFT and BNCT therapeutic modalities, warranting further studies on carrier-free [o-FESAN]− as a candidate drug for potential clinical translation of radio enhancers in binary radiation therapies.
- TLD measurements and Monte Carlo simulations for glandular dose and scatter fraction assessment in mammography: a comparative studyPublication . Di Maria, Salvatore; Barros, Sílvia; Bento, Joana; Teles, Pedro; Figueira, Catarina; Pereira, Matheus; Vaz, P.; Paulo, GracianoThe main purpose of this study was to validate and compare Mean Glandular Dose (MGD) values obtained using Monte Carlo simulations with experimental values obtained from Entrance Surface Dose (ESD) and depth dose measurements performed in a Hospital mammography unit. ESD and depth dose were measured using ThermoLuminescent Dosimeters (TLDs), and a tissue equivalent mammography phantom recommended by the American College of Radiology (ACR). Measurements and Monte Carlo simulations were also compared with the MGD calculated using the Automatic Exposure Control (AEC) system of the mammographic unit. In the simulations the Doppler energy broadening effect was also taken into account. The simulated ESD are about 5%-10% higher than the measured ESD values. The deviation between the measured and simulated MGD values in the phantom is of about 15%. The MGD evaluated using the AEC system is smaller both with respect to the Monte Carlo simulation and experimental result by a factor of about 15% and 25% respectively. Moreover the BackScatter Factor (BSF) estimated by Monte Carlo simulations was used for the MGD calculation according to the Wu's method. Finally the inclusion of the energy broadening effect on MGD calculation produces negligible variations on the simulated results.