RESUMO
A dosimetry intercomparison between the boron neutron capture therapy groups of the Massachusetts Institute of Technology (MIT) and the Comisión Nacional de Energía Atómica (CNEA), Argentina was performed to enable combined analyses of NCT patient data between the different centers. In-air and dose versus depth measurements in a rectangular water phantom were performed at the hyperthermal neutron beam facility of the RA-6 reactor, Bariloche. Calculated dose profiles from the CNEA treatment planning system NCTPlan that were calibrated against in-house measurements required normalizations of 1.0 (thermal neutrons), 1.13 (photons), and 0.74 (fast neutrons) to match the dosimetry of MIT.
Assuntos
Terapia por Captura de Nêutron de Boro/estatística & dados numéricos , Terapia por Captura de Nêutron de Boro/normas , Radiometria/estatística & dados numéricos , Argentina , Calibragem , Humanos , Massachusetts , Radiometria/normas , Dosagem Radioterapêutica , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Irregular fields for boron neutron capture therapy (BNCT) have been already proposed to spare normal tissue in the treatment of superficial tumors. This added dependence would require custom measurements and/or to have a secondary calculation system. As a first step, we implemented the sector-integration method for irregular field calculation in a homogeneous medium and on the central beam axis. The dosimetric responses (fast neutron and photon dose and thermal neutron flux), are calculated by sector integrating the measured responses of circular fields over the field boundary. The measurements were carried out at our BNCT facility, the RA-6 reactor (Argentina). The input data were dosimetric responses for circular fields measured at different depths in a water phantom using ionisation and activation techniques. Circular fields were formed by shielding the beam with two plates: borated polyethilene plus lead. As a test, the dosimetric responses of a 7x4 cm(2) rectangular field, were measured and compared to calculations, yielding differences less than 3% in equivalent dose at any depth indicating that the tool is suitable for redundant calculations.