[Personalized low-melting alloy shield for high-energy electrons in the treatment of superficial neoplasms of critical or esthetically important regions]. / Schermature personalizzate in lega bassofondente per elettroni di alta energia nel trattamento di neoplasie superficiali situate in regioni estetiche o critiche.

Individualized Cerrobend beam shapings for high-energy electrons have been utilized in the treatment of superficial tumours located in aesthetic or critical regions. Individualized cellulose acetate masks have been used as immobilization device. Measured transmissions through Cerrobend ranged from 0.5% at 4 MeV to 8.5% at 18 MeV. Phantom dosimetry showed a poor influence of Cerrobend on PDD (percentage depth doses). Output factor variations appeared to depend on electron energy and shielded area. It is very important to perform either empirical measurements or to adopt semiempirical models in order to exactly calculate those output factors. Three clinical examples are presented: the utilization of immobilization device and field shaping are illustrated with the main aim of sparing the dose to critical organs.