Dosimetric and bremsstrahlung Performance of a Single Convergent Beam for Teletherapy Device

R. FIGUEROA; M. SANTIBANEZ; M. VALENTE

PHYSICA MEDICA

IST EDITORIALI POLGRAFICI INT

Lugar: Roma; Año: 2016 vol. 32 p. 1489 - 1494

1120-1797

The present work investigates preliminary feasibility and characteristics of a new type ofradiation therapy modality based on a single convergent beam of photons. The proposalconsists of the design of a device capable of generating convergent x-ray beams useful forradiotherapy. The main goal is to achieve high concentrated dose delivery. The first step is ananalytical approach in order to characterize the dosimetric performance of the hypotheticalconvergent photon beam. Then, the validated FLUKA Monte Carlo main code is used toperform complete radiation transport to account also for scattering effects. The proposedmethod for producing convergent x-rays is mainly based on the bremsstrahlung effect. Hencethe operating principle of the proposed device is described in terms of bremsstrahlungproduction. The work is mainly devoted characterizing the effect on the bremsstrahlung yielddue to accessories present in the device, like anode material and geometry, filtration andcollimation systems among others.The results obtained for in-depth dose distributions, by means of analytical and stochasticapproaches, confirm the presence of a high dose concentration around the irradiated target, asexpected. Moreover, it is shown how this spot of high dose concentration depends upon therelevant physical properties of the produced convergent photon beam.In summary, the proposed design for producing single convergent x-rays attained satisfactoryperformance for achieving high dose concentration around small targets depending on beamspot size that may be used for some applications in radiotherapy, like radiosurgery.