Investigation of TLD-700 energy response to low energy x-ray encountered in diagnostic radiology

Abstract

Abstract:The aim of this work is to study the energy dependence of thermoluminescent dosimeter (TLD-700) for low energy X-ray beams encountered in conventional diagnostic radiology. In the rst step, we studied some characteristics (reproducibility and linearity) of TLD-700 chips using a Cs source, and selected TLD chips with reproducibility better than 2.5%. Then we determined TLD-700 energy response for diagnostic radiology X-ray qualities, and investigated its in uence on air kerma estimate. A maximum deviation of 60% can be obtained if TLDs are calibrated for Cs radiation source and used in diagnostic radiology elds. However, this deviation became less than 20% if TLDs chips are calibrated for the reference x-ray radiation quality RQR5 (recommended by the IEC 61267 standard). Consequently, we recommend calibrating this kind of TLD detector with RQR5 diagnostic radiology X-ray quality. This method permits to obtain a good accuracy when assessing the entrance dose in diagnostic radiology procedures.

Determination of Calibration Factors and Uncertainties Associated with the Irradiation of MTS-N (LiF: Mg, Ti) Chips with Cesium-137 and X-ray Sources Under Low Doses for Personal Dosimetry in Diagnostic Radiology

“…There are few studies on the use of low radiation dose with TL calibration in conventional radiography, where uncertainty in personal equivalent dose is most likely to be high. A study by Herrati et al pointed out that uncertainty in deviation can reach 60% with low doses (17). Sabar et al, likewise, reported that there could be very high deviation (above 40%) below 0.3mGy (18).…”

Comparison of entrance surface air kerma measurement with MTS-N (LiF: Mg, Ti) chips with a kilovoltage X-ray source

“…High deviations at low doses using different types of TLDs have been reported. For instance, an investigation to the effect of TLD-700 energy response at low energy X-ray encountered in diagnostic radiology using caesium-137 source by Herrati et al, shows that maximum deviation could reach 60% and his study also shows that with the use of appropriate radiation quality (RQR5), dose accuracy can be reduced by up to 20% [22]. Alashrah et al in his study also reported a deviation up to 50% at the surface of a water phantom at a depth of 0.007cm as recommended by the International Commission on Radiological Protection (ICRP) and the International Commission on Radiation Units and Measurement (ICRU) with radiochromic films (RFs), thermoluminescent dosimeters and an ionization chamber with a 6-MV photon beam [23].…”