Authors: AYŞE GÜNEŞ TANIR, FATMA SERAP KETENCİ, MUSTAFA HİCABİ BÖLÜKDEMİR
Abstract: The total attenuation coefficients of 11 biological targets against photon energies were plotted within the energy range 1-10 MeV. From these plots a possible equation describing the relationship between photon energy and the total attenuation coefficient was derived. The suggested equation is mu/ rho = 0.0696/ surd E. To test the validity of the equation and to compare the results of the total attenuation coefficients of 3 tissue-equivalent materials (bolus, rice grains, and boiled rice) that could not be determined before, they were determined experimentally by using X-rays produced at 6 MV and 18 MV. The results of the experiment show a relatively good match with the computed values using the suggested equation. It is possible to conclude that 1) the suggested equation is a practical way to define the total attenuation coefficients of biological tissue or tissue-equivalent materials and 2) the attenuation coefficient is one of the most important to determine the absorbed dose by patients and so they should be worked out experimentally before treatment.
Keywords: Attenuation coefficients, radiotherapy, tissue equivalent materials
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