The use of TLDs for brachytherapy dosimetry

• Brachytherapy measurements with LiF:Mg,Ti TLDs performed.
• Intrinsic energy dependence for several brachytherapy sources determined.
• New LiF:Mg,Ti energy dependence results compared with previous data for x-ray beams.
• Uncertainty of LiF:Mg,Ti TLD measurements reviewed.

Thermoluminescent dosimeters (TLDs) are routinely used to measure the dose around brachytherapy sources due to their small size and high precision. This work presents a concise overview of the use of LiF:Mg,Ti TLDs for brachytherapy dosimetry including the experimental procedures required to achieve high-precision measurements as well as new results regarding the intrinsic energy dependence with some of the commonly used brachytherapy sources. Equations to correct TLD light output to air kerma are outlined and a description of the method to determine the intrinsic energy dependence is presented. For the intrinsic energy dependence investigation, a review of previously published results is presented as well as new experimental results using 125I, 103Pd, 192Ir, and miniature x-ray brachytherapy sources at the University of Wisconsin Medical Radiation Research Center (UWMRRC). The results of these experiments are consistent with previous work and give valuable insight to investigators using TLDs for brachytherapy measurements.