Application of luminescent detectors in quality assurance of clinical electron beam

Abstract

Thermoluminescent dosimeters (TLD) are widely applied in quality assurance of external radiotherapy beam. The aim of this study is to check the possible use of radiophotoluminescent glass dosimeters (RPLGD), and optically stimulated luminescent dosimeters (OSLD) in quality assurance of clinical electron beam (used in radiotherapy treatments). For this purpose, we give in this paper, an estimation and a comparison of dosimetric parameters, characterizing dose profile and percentage depth dose (PDD) curves, for electron beam using the different studied detectors. The Monte Carlo MCNP5 simulation code was utilized to calculate the distribution of deposited energy along X-axis and PDD curves in a water phantom using RPLGD (FD-7glass), TLD (LiF: Mg, Ti) and OSLD (Al2O3:C) for electron beam energies of 9, 12, 16 and 20 MeV. Our calculations show that the profiles for different electron energies are almost identical for all used materials: we found similar average penumbra and full width at half maximum (FWHM). For flatness and symmetry, our results show a good correspondence with the recommended values where the flatness and symmetry calculated in all dosimeters materials are less than 1.7%. We also found concordance with the literature for the parameters derived from PDD curves, such as various ranges (R100, R90, R80, R50 and Rp) and energies specification (Ep,o and E0) for different electron beams (9, 12, 16 and 20 MeV). In conclusion, this study demonstrates a good correspondence with the results of measurements and Monte Carlo simulations found in the literature. RPLGD and OSLD can be as TLD useful detectors for quality assurance (QA) verifications concerning dose profile and PDD curve for clinical electron beam. Further research is recommended to broaden the scope of the current study.

Geometrical effects on luminescent dosimeter energy response

“…Luminescent dosimeters are materials that emit a quantity of light, proportional to the absorbed ionizing radiation when irradiated. There are three main groups of luminescence detectors applied in clinical dosimetry: thermo-luminescence dosimeter (TLD), Optically stimulated luminescence dosimeter (OSLD) and Radiophotoluminescent glass dosimeters (RPLD) [1][2][3][4].…”