Comparison of LiF (TLD-100 and TLD-100H) detectors for extremity monitoring

In this work the results aimed at assessing the performance of two types of LiF detectors, TLD-100 and TLD-100H. used in the context of extremity dosimetry are presented. Each detector variety was studied for reproducibility, batch homogeneity, residual dose, linearity and energy dependence using, when appropriate, the Sr-90/Y-90 radiation source built-in one of the Harshaw 6600 readers, the ISO narrow X-ray beams of N30, N40, N60, N80, N100 and N120 or the gamma radiations of Cs-137 and Co-60. Two calibration energies (N120 and (CS)-C-137) were also used. The reproducibility and linearity results indicate that both LiF:Mg,Ti and LiF:Mg,Cu,P performed equally well. However, LiF:Mg,Cu,P presents a higher residual signal. In terms of energy dependence, LiF:Mg,Cu,P shows less variation than LiF:Mg,Ti particularly when N120 is used as calibration radiation. This seems to be a more realistic setup since the energy of the most frequently used radioisotopes in Nuclear Medicine departments with single photon emission computed tomography (SPECT) use gamma radiation energies closer to N120 than to 137CS. (C) 2008 Elsevier Ltd. All rights reserved.