Evaluating the effect of energy on calibration of thermo-luminescent dosimeters 7-LiF:Mg,Cu,P (GR-207A)

Background: 7-lif: mg,cu,p (gr-207a) is one kind of thermo-luminescent dosimeters (tld) which can be used in diagnostic radiology and radiotherapy applications. because of having suitable properties such as good sensitivity, small size and being tissue equivalent, thermo-luminescent dosimetry has been one of the most important techniques in medicine over many years. choosing a correct energy for tlds’ calibratioon is one of the most important factors in the accuracy of the absorbed dose. materials and methods: in order to evaluate the effect of calibration energy on the response of gr-207a tlds, calibration of the tlds were done with 120kvp, 200kvp, 6mv, 18mv and 60 ^co beams. then the responses of tlds were normalized to 60^co and energy dependence was calculated for each dose step. results: the results confirmed that this kind of tld dose not have the same response in different energies and reference dose affects on the amount of energy dependence.discussion: energy dependence of this type of tlds is more significant atlower energies compared to megavoltage beams. relative response to 60^co illustrates that gr-207a dose not have uniform response to different steps ofenergies and the amount of energy dependence is totally different in variousdose levels.