Characterization of CaF2:Dy (TLD-200) dosimeters and determination of dosimetric quantities in mammography

Abstract

This study aimed to characterize CaF2:Dy (TLD-200) thermoluminescence dosimeter (TLD) in mammography, and to determine entrance surface dose (ESD), relative depth dose (RDD), and mean glandular dose (MGD) values. The angular and energy dependencies, dose-response, and TL intensity reproducibility characteristics of dosimeters were investigated. The dosimeters showed a linear dose-response behavior corresponding to air kerma values ranging between 2.11 and 21.98 mGy and a reproducibility of ±5%. The response of the dosimeters showed by ∼48% over response when the tube potential increased from 22 to 32 kVp, indicating that they have a substantial energy dependence. On the other hand, the TL intensity at 90° decreased by 70% compared with that at 0°, when the angular dependence of dosimeters was investigated. The ESD and MGD values obtained for both polymethyl methacrylate (PMMA) and BR-12 phantoms were compatible with existing literature, and the MGD values were also agreed with the European Federation of Organisations for Medical Physics (EFOMP). The RDD value decreased by nearly 90% at 6 cm depth. These dosimetric quantities did not change considerably for PMMA and BR-12 phantoms. The results showed that TLD-200 could be used as an alternative dosimeter in mammography to determine dosimetric quantities.