Sensitivity of Alanine Dosimeters with Gadolinium Exposed to 6 MV Photons at Clinical Doses

In this study we analyzed the ESR signal of alaninedosimeters with gadolinium exposed to 6 MV linearaccelerator photons. We observed that the addition ofgadolinium brings about an improvement in the sensitivity to photons because of its high atomic number. Theexperimental data indicated that the addition of gadolinium increases the sensitivity of the alanine to 6 MV photons. This enhancement was better observed at high gadolinium concentrations for which the tissue equivalence is heavily reduced. However, information about the irradiation setup and of the radiation beam features allows one to correct forthis difference. Monte Carlo simulations were carried out toobtain information on the expected effect of the addition of gadolinium on the dose absorbed by the alanine molecules inside the pellets. These results are compared with theexperimental values, and the agreement is discussed.