THERMOLUMINESCENT DOSIMETRY:
Introduction:
Ionizing radiations have been used during the last century for many uses, mainly in clinical applications such as diagnostic radiology and radiotherapy. Advances in radiotherapy have increased the use of cobalt units and linear acceleretors, and have also increased the number and types of the therapeutic techniques used.
Although the benefits of the application of radiations, the detrimental effects of exposure to radiations, such as induction of cancer and genetic deffects, have led to tighter controls on the dose received. In radiotherapy because of the high delivered doses to the patient, subsequently, the accurate measurement of dose absorbed by the tissue became of importance. Related to this topic, in 1976, the ICRU(International Comission on Radiation Units and Measurements) recommended that the dose to the target volume should be delivered to within +-5%.
At this time treatment planning in radiotherapy is realized by means of complex computer codes that calculate the dose distribution in the patient. However, it is obvious that 'in vivo' verification of patient treatment is needed to check inaccuracies such as errors in the computer dose calculation or errors in the patient set-up, and so on.
Thermoluminescence:
Thermoluminescent detectors can absorb the deposited energy of the radiation, store a fraction of it, and convert it into optical radiation (luminescence) when heated.
The association of luminescence, and in particular thermoluminescence (TL) with exposure of a material to the radiations was observed by the pioneers of research in radioactivity. Marie Curie observed and noted the thermoluminescence of calcium fluoride in her doctoral thesis, and in 1953 Daniels et al proposed TL as a system to make quantitative measurements of radiation exposure, [McKinlay, 1981].
Up to now, thermoluminescence of many materials have been studied and have been applied to many areas as personal, environmental, and clinical dosimetry, and in fields as dating.
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