Thyroids Dose Evaluation and Calculation of Backscatter Factors for Co-60 Irradiations

The aim of the study is evaluation of absorbed doses for thyroids by using neck phantoms. For this purpose, it was arranged the irradiation set with different phantoms. Three different materials were used for phantom materials as, water, paraffin and wood. The phantoms were three different dimensions for simulation of different ages and human race for each material. Co-60 gamma source was used for irradiation and the experimental procedure applied rigorously with narrow beam geometry. As the results of the experiments the relative radiation doses are evaluated for therapeutic applications for thyroids and backscattering factors were calculated and shown that water, paraffin and wood can appropriate for phantom material with the converge values of backscattering factors. Keywords—Co-60, Dosimetry, phantom, thyroids.