María Pedrosa Rivera | Universidad de Granada (original) (raw)

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Papers by María Pedrosa Rivera

The experimental determination of the relative biological effectiveness of thermal neutron factor... more The experimental determination of the relative biological effectiveness of thermal neutron factors is fundamental in Boron Neutron Capture Therapy. Present values have been obtained using mixed beams consisting of both neutrons and photons of various energies. A common weighting factor has been used for both thermal and fast neutron doses, although such an approach has been questioned. At the nuclear reactor of the Institut Laue-Langevin a pure low-energy neutron beam has been used to determine thermal neutron relative biological effectiveness factors. Different tumor cell lines, corresponding to glioblastoma, melanoma, and head and neck squamous cell carcinoma, and non-tumor cell lines (lung fibroblast and embryonic kidney) have been irradiated using an experimental arrangement designed to minimise neutron-induced secondary gamma radiation. Additionally, the cells were irradiated with photons at a medical linear accelerator, providing reference data for comparison with that from ne...

Applied Radiation and Isotopes, 2020

The cold neutron beam at the PF1b line at the Institut Laue-Langevin (ILL), without fast neutrons... more The cold neutron beam at the PF1b line at the Institut Laue-Langevin (ILL), without fast neutrons and a low contribution of gamma rays, is a very suitable facility to measure cell damage following low-energy neutron irradiation. The biological damage associated with the thermal and the boron doses can be obtained in order to evaluate the relative biological effectiveness (RBE) for Boron Neutron Capture Therapy. Three different experiments were carried out on the A375 melanoma cell line: the first one in a hospital LINAC, to obtain the reference radiation data, and the other two at the ILL, in which the damage to cells with and without boron compounds added was measured.

Applied Radiation and Isotopes, 2020

The Granada group in BNCT research is currently performing studies on: nuclear and radiobiologica... more The Granada group in BNCT research is currently performing studies on: nuclear and radiobiological data for BNCT, new boron compounds and a new design for a neutron source for BNCT and other applications, including the production of medical radioisotopes. All these activities are described in this report.

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2020

Data on the radiobiological effects of thermal neutrons are usually obtained from irradiations in... more Data on the radiobiological effects of thermal neutrons are usually obtained from irradiations in a mixed field of neutrons of different energies and gamma rays or from conversion of proton data with similar energies to those created in the neutron capture on nitrogen. Experimental data from irradiations in a pure thermal or cold neutron beam can help to find new values for neutron relative biological effectiveness (RBE) factors, which are useful for BNCT (Boron Neutron Capture Therapy) and radiation protection applications. We present a new experimental setup for radiobiological studies at a cold neutron beam at Institut Laue-Langevin, a beam without fast neutron component and almost no gamma ray contribution. After the irradiation, survival assays are performed to obtain the survival curves. Finally, comparing with a reference photon irradiation, the thermal neutron RBE factors can be calculated. The methodology is outlined at the example of A375 melanoma cells for which new radiobiological data were obtained.

Applied Radiation and Isotopes, 2019

The current methodology for determining the biological effect of Boron Neutron Capture Therapy (B... more The current methodology for determining the biological effect of Boron Neutron Capture Therapy (BNCT) has recently been questioned, and a more accurate framework based in the photon isoeffective dose has been proposed. In this work we derive a first order approximation to this quantity than can be easily evaluated even from limited data, as is the current situation in the radiobiology of BNCT. This procedure removes the main drawbacks of the current method and it is based on new weighting factors that, as a difference with the previously used, are true constants (dose independent). In addition to this, we apply the formalism to allow the comparison to a fractionated conventional radiotherapy treatment, for which there is a lot of knowledge from clinical practice. As an application, the photon isoeffective dose of a BNCT treatment for a brain tumor is estimated. An excel sheet used for these calculations is also provided as supplementary material and can be used also with user-provided input data for the estimation of the photon isoeffective dose for comparison with conventional radiotherapy, both to single and fractionated treatments.

The experimental determination of the relative biological effectiveness of thermal neutron factor... more The experimental determination of the relative biological effectiveness of thermal neutron factors is fundamental in Boron Neutron Capture Therapy. Present values have been obtained using mixed beams consisting of both neutrons and photons of various energies. A common weighting factor has been used for both thermal and fast neutron doses, although such an approach has been questioned. At the nuclear reactor of the Institut Laue-Langevin a pure low-energy neutron beam has been used to determine thermal neutron relative biological effectiveness factors. Different tumor cell lines, corresponding to glioblastoma, melanoma, and head and neck squamous cell carcinoma, and non-tumor cell lines (lung fibroblast and embryonic kidney) have been irradiated using an experimental arrangement designed to minimise neutron-induced secondary gamma radiation. Additionally, the cells were irradiated with photons at a medical linear accelerator, providing reference data for comparison with that from ne...

Applied Radiation and Isotopes, 2020

The cold neutron beam at the PF1b line at the Institut Laue-Langevin (ILL), without fast neutrons... more The cold neutron beam at the PF1b line at the Institut Laue-Langevin (ILL), without fast neutrons and a low contribution of gamma rays, is a very suitable facility to measure cell damage following low-energy neutron irradiation. The biological damage associated with the thermal and the boron doses can be obtained in order to evaluate the relative biological effectiveness (RBE) for Boron Neutron Capture Therapy. Three different experiments were carried out on the A375 melanoma cell line: the first one in a hospital LINAC, to obtain the reference radiation data, and the other two at the ILL, in which the damage to cells with and without boron compounds added was measured.

Applied Radiation and Isotopes, 2020

The Granada group in BNCT research is currently performing studies on: nuclear and radiobiologica... more The Granada group in BNCT research is currently performing studies on: nuclear and radiobiological data for BNCT, new boron compounds and a new design for a neutron source for BNCT and other applications, including the production of medical radioisotopes. All these activities are described in this report.

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2020

Data on the radiobiological effects of thermal neutrons are usually obtained from irradiations in... more Data on the radiobiological effects of thermal neutrons are usually obtained from irradiations in a mixed field of neutrons of different energies and gamma rays or from conversion of proton data with similar energies to those created in the neutron capture on nitrogen. Experimental data from irradiations in a pure thermal or cold neutron beam can help to find new values for neutron relative biological effectiveness (RBE) factors, which are useful for BNCT (Boron Neutron Capture Therapy) and radiation protection applications. We present a new experimental setup for radiobiological studies at a cold neutron beam at Institut Laue-Langevin, a beam without fast neutron component and almost no gamma ray contribution. After the irradiation, survival assays are performed to obtain the survival curves. Finally, comparing with a reference photon irradiation, the thermal neutron RBE factors can be calculated. The methodology is outlined at the example of A375 melanoma cells for which new radiobiological data were obtained.

Applied Radiation and Isotopes, 2019

The current methodology for determining the biological effect of Boron Neutron Capture Therapy (B... more The current methodology for determining the biological effect of Boron Neutron Capture Therapy (BNCT) has recently been questioned, and a more accurate framework based in the photon isoeffective dose has been proposed. In this work we derive a first order approximation to this quantity than can be easily evaluated even from limited data, as is the current situation in the radiobiology of BNCT. This procedure removes the main drawbacks of the current method and it is based on new weighting factors that, as a difference with the previously used, are true constants (dose independent). In addition to this, we apply the formalism to allow the comparison to a fractionated conventional radiotherapy treatment, for which there is a lot of knowledge from clinical practice. As an application, the photon isoeffective dose of a BNCT treatment for a brain tumor is estimated. An excel sheet used for these calculations is also provided as supplementary material and can be used also with user-provided input data for the estimation of the photon isoeffective dose for comparison with conventional radiotherapy, both to single and fractionated treatments.