Publicação
Estudo da radiossensibilização de células tumorais do pâncreas com nanopartículas
| Resumo: | Introduction: Pancreatic cancer is the seventh leading cause of death by cancer in developed countries. Its high mortality rate is related to the difficulty of a diagnosis in its initial stages and also because these tumors are very resistant to conventional treatments. Thus, it is of extreme importance to find new treatment strategies for this disease. The main objective of this study was to assess the effect of the presence of gold nanoparticles (GNPs) on pancreatic cancer cells when irradiated with photons through Monte Carlo simulations. Materials and methods: All simulations were done using TOPAS-nBio code. Three different types of human pancreatic cancer cell lines were selected: BxPC-3, PANC-1 and Mia PaCa-2. Additionally, 104 spheric gold nanoparticles with 100 nm of diameter were randomly distributed through the cytoplasm of each cell. A monolayer of cells was simulated and irradiated with a monochromatic beam of 50 keV, a Cobalt-60 source, and one beam of 6 MV X-Rays from a clinic linear accelerator with three different setups: 1) Irradiation perpendicular to the layer of cells with a narrow beam with the width of the central cell; 2) Irradiation perpendicular to the layer of cells with a wide beam with the width of the culture of cells; and 3) Irradiation parallel to the cell culture with a narrow beam with the width of a single cell. For the central cell and the groups composed by the first, second and third neighboring cells of the central cell, the values of normalized dose to the central cell and the Dose Enhancement Factor (DEF) values, given by the ratio between the delivered dose with and without GNPs in a radiotherapy treatment, were calculated. Results: For the BxPC-3 cells, DEF values in the range of 0.63 to 4.34 were obtained. For the perpendicular irradiation with the narrow beam, irradiating only the central cell, the DEF values in this cell were 1.05 for 50 keV and Co-60, and 1.27 for 6 MV. Independently of the irradiation source, there was a larger radiosensitizing effect in the neighboring cells, that weren’t irradiated with the primary beam, when compared to the central cell. A maximum DEF value of 1.39 for the first neighbors with the 50 keV beam, 1.60 for the second neighbors with a Co-60 source and 1.36 for the third neighbors with 6 MV were obtained. Similarly, for the paralel irradiation with a narrow beam, a maximum DEF of 2.11 for the second neighbors with a Co-60 source and 2.29 for the third neighbors with 6 MV was obtained. For the perpendicular irradiation with a wide beam, the maximum DEF values were obtained in the central cell having a value of 4.34 and 2.84 for 50 keV and 6 MV, respectively. For the PANC-1, irradiated with a narrow beam, the DEF values ranged between 0.98 and 1.58. Conclusion: The presence of GNPs in a cell irradiated with photon beams also radiosensitizes neighboring cells. In the presence of GNPs the delivered dose on a cell of a specific culture is also due to the deposition of energy by action of secondary particles created by the nanoparticles in its neighboring cells. The 50 keV source produced the largest DEF values when compared to the other sources: Co-60 and 6 MV. Although the radiosensitizing effect was also produced when using these energies in the presence of GNPs. |
|---|---|
| Autores principais: | Fernandes, Nísia Santos |
| Assunto: | Cancro Pancreático Radioterapia Nanopartículas de Ouro Efeito Radiossensibilizador Simulações de Monte Carlo Teses de mestrado - 2022 |
| Ano: | 2022 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | português |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Introduction: Pancreatic cancer is the seventh leading cause of death by cancer in developed countries. Its high mortality rate is related to the difficulty of a diagnosis in its initial stages and also because these tumors are very resistant to conventional treatments. Thus, it is of extreme importance to find new treatment strategies for this disease. The main objective of this study was to assess the effect of the presence of gold nanoparticles (GNPs) on pancreatic cancer cells when irradiated with photons through Monte Carlo simulations. Materials and methods: All simulations were done using TOPAS-nBio code. Three different types of human pancreatic cancer cell lines were selected: BxPC-3, PANC-1 and Mia PaCa-2. Additionally, 104 spheric gold nanoparticles with 100 nm of diameter were randomly distributed through the cytoplasm of each cell. A monolayer of cells was simulated and irradiated with a monochromatic beam of 50 keV, a Cobalt-60 source, and one beam of 6 MV X-Rays from a clinic linear accelerator with three different setups: 1) Irradiation perpendicular to the layer of cells with a narrow beam with the width of the central cell; 2) Irradiation perpendicular to the layer of cells with a wide beam with the width of the culture of cells; and 3) Irradiation parallel to the cell culture with a narrow beam with the width of a single cell. For the central cell and the groups composed by the first, second and third neighboring cells of the central cell, the values of normalized dose to the central cell and the Dose Enhancement Factor (DEF) values, given by the ratio between the delivered dose with and without GNPs in a radiotherapy treatment, were calculated. Results: For the BxPC-3 cells, DEF values in the range of 0.63 to 4.34 were obtained. For the perpendicular irradiation with the narrow beam, irradiating only the central cell, the DEF values in this cell were 1.05 for 50 keV and Co-60, and 1.27 for 6 MV. Independently of the irradiation source, there was a larger radiosensitizing effect in the neighboring cells, that weren’t irradiated with the primary beam, when compared to the central cell. A maximum DEF value of 1.39 for the first neighbors with the 50 keV beam, 1.60 for the second neighbors with a Co-60 source and 1.36 for the third neighbors with 6 MV were obtained. Similarly, for the paralel irradiation with a narrow beam, a maximum DEF of 2.11 for the second neighbors with a Co-60 source and 2.29 for the third neighbors with 6 MV was obtained. For the perpendicular irradiation with a wide beam, the maximum DEF values were obtained in the central cell having a value of 4.34 and 2.84 for 50 keV and 6 MV, respectively. For the PANC-1, irradiated with a narrow beam, the DEF values ranged between 0.98 and 1.58. Conclusion: The presence of GNPs in a cell irradiated with photon beams also radiosensitizes neighboring cells. In the presence of GNPs the delivered dose on a cell of a specific culture is also due to the deposition of energy by action of secondary particles created by the nanoparticles in its neighboring cells. The 50 keV source produced the largest DEF values when compared to the other sources: Co-60 and 6 MV. Although the radiosensitizing effect was also produced when using these energies in the presence of GNPs. |
|---|