TL and OSL dosimetric characterization of different luminescent materials for clinical electron beams application in TSI treatments

Abstract

Thermoluminescent dosimeters (DTLs) play an important role in radiotherapy for the dosimetry of ionizing radiation. This type of dosimeter presents advantages that makes them a useful tool, in particular, for measurements in anthropomorphic simulators and for dosimetry in vivo in patients. Several dosimetric materials have been used in the radiotherapy sectors such as LiF, LiF, CaSO4:Dy(1,2). The OSL dosimetry has also been widely used using Aluminum Oxide (Al2O3: C). These dosimeters have advantages over DTLs due to their high sensitivity, extensive linearity in response to the dose, faster readability, possibility of multiple re-readings and the need to perform the heat treatment of the samples(3). The objective of this work was to characterize the TL and OSL techniques using different luminescent dosimeters (LiF, LiF, CaSO4:Dy and Al2O3:C) to be applied in clinical electron beam used to TSI (Total Skin Irradiation) treatments. Parameters such as dose response curve, that presented linear behavior in the dose range studied; mean sensitivity of the dosimeters, that demonstrated constant values in the dose range analyzed: 28,7 cGy to 382,8 cGy were evaluated. Other parameters also studied were the angular dependence of the TL and OSL response and the intrinsic efficiency of the materials. The Al2O3:C dosimeters presented variation of the OSL response greater than the other dosimeters, probably, due to their thickness 0,9 mm.