RESUMO
Polymeric gel dosimeters are being used to verify three-dimensional (3D) dose distributions of different types of radiotherapy treatments, especially the most complexes ones. An important factor that can limit the wider use of this kind of dosimeter is temperature, as gel melting can destroy 3D information. This work shows that adding formaldehyde to the gel preparation increases the melting point, allowing its use in warmer environments, including up to body temperature. An addition of 3% in mass of the formaldehyde solution to a MAGIC type gel dosimeter increased its melting point from 25 to 69 degrees C. Also important were a 12.5% increase in gel sensitivity and an expressive decrease in relaxation rate R2 uncertainty.
Assuntos
Ácido Ascórbico/química , Sulfato de Cobre/química , Formaldeído/química , Gelatina/química , Hidroquinonas/química , Metacrilatos/química , Polímeros/química , Doses de Radiação , Temperatura de Transição , Sensibilidade e EspecificidadeRESUMO
Functional MRI produces a more accurate localization of the language areas for epilepsy surgery purpose, but requires the patient's cooperation. We report a 34 year-old woman with mental retardation who underwent two different verbal fluency tasks, category and word naming. We found a strong activation of Broca's area in the most difficult task. We suggest that a multi-task fMRI study could be successful in patients with cognitive delay.