Ponente
Descripción
Boron Neutron Capture Therapy (BNCT) is a neutron-based treatment designed to eliminate tumors, mainly head and neck tumors or Glioblastoma Multiforme (GBM), using 1 or 2 sessions, which is an advantage over conventional therapies that could use more than 20 individual sessions. It is a two-step strategy: first, the administration of a boron-containing compound to selectively enrich tumor cells with boron-10 nuclei; and second, irradiation with thermal neutrons. The aim is to induce reactions between thermal neutrons and boron-10 nuclei, releasing high-LET alpha particles with an average range shorter than the cell size. This feature gives BNCT a highly selective and destructive character, maximizing the dose contrast between tumor and healthy tissue.
The uptake of boron-rich nanoparticles and the response to BNCT can be studied in-vitro with cell cultures. This requires access to a source of thermal neutrons at very high flux. In this work, a nanoparticle-based boron compound was tested through a series of experiments carried out at the TRIGA nuclear reactor in Mainz. The objectives focused on the one hand, on characterizing the background dose generated by the reactor. For this purpose, pre-calibrated radiochromic films (RCF) were used under different reactor power and irradiation time configurations. In some experiments, parts of the RCF were covered with cadmium or lead to attenuate this background dose. These results allow for estimating the dose absorbed by a cell population exposed to the reactor in the absence of alpha particle production. It is worth noting that this dose originates both from the photon background and from fast, unmoderated neutrons emitted from the reactor core.
On the other hand, aqueous solutions of the boron-containing compound were prepared at different concentrations and irradiated under variable power and time conditions in wells of Petri plates. The well openings were covered with PADC (CR-39) detectors to register alpha-particle tracks generated by the interaction between boron-10 nuclei and thermal neutrons. After etching, holes associated with alpha particles were observed, superimposed on a rough background attributed to secondary protons produced by fast neutrons. These observations qualitatively confirm alpha production.
As a future perspective, we plan to use cell lines incubated with these boron-based nanoparticles to evaluate both the absorbed dose and the cell survival fraction under nuclear reactor irradiation.
