A comparative study for different shielding material composition and beam geometry applied to PET facilities: simulated transmission curves

Abstract

The aim of this work is to simulate transmission data for different beam geometry and material composition in order to evaluate the effect of these parameters on transmission curves. The simulations are focused on outgoing spectra for shielding barriers used in PET facilities. The behavior of the transmission was evaluated as a function of the shielding material composition and thickness using Geant4 Monte Carlo code, version 9.2 p 03.The application was benchmarked for barited mortar and compared to The American Association of Physicists in Medicine (AAPM) data for lead. Their influence on the transmission curves as well the study of the influence of the shielding material composition and beam geometry on the outgoing spectra were performed. Characteristics of transmitted spectra, such as shape, average energy and Half-Value Layer (HVL), were also evaluated. The Geant4 toolkit benchmark for the energy resulting from the positron annihilation phenomena and its application in transmission curves description shown good agreement between data published by American Association on Physicists in Medicine task group 108 and experimental data published by Brasil. The transmission properties for different material compositions were also studied and have shown low dependency with the considered thicknesses. The broad and narrow beams configuration presented significant differences on the result. The fitting parameter for determining the transmission curves equations, according to Archer model is presented for different material. As conclusion were defined that beam geometry has significant influence and the composition has low influence on transmission curves for shielding design for the range of energy applied to PET.

Narrow and Broad Beam Attenuation of Diagnostic X Ray Beam Across Lead Sample Found in Ebonyi State, South East Nigeria

“…Currently, the country intends to build more Radiotherapy centers across the federation. Available broad beam data are found to be unsatisfactory and according to Hoff [12] ; the adequate characterization of a shielding material is important for supporting efficient radiation shielding design processes. The authors believe that the result of this study will give basic information on the radiation shielding capacity of the lead sample deposit found in Ebonyi state.…”