Optimization of PAVAgNO3 Films for Measuring Entrance and Exit Radiotherapy Dose Relative to TLDs

The aim of this study was to synthesize the PVAAgNO3 polymer films and to optimize it is radiation measurement based on entrance and exit dose measurement relative to thermoluminiscence detector (TLD) method. The polymer films have been synthesized by casting technique after dissolving of polyvinyl alcohol (PVA) under controlled temperature (80 C) and stirring and hybridization with silver nitrate (AgNO3). The polymer films have been characterized after irradiation at the entrance and exit sites of Perspex by UV-visible spectroscopy and an optical densitometer (OD). The study revealed that there were absorption peaks at wavelength () 190 and 425 nm related to pure PVA and silver out of UV-visible spectroscope, and the average entrance and exit doses read by TLD was 7.064.7 and 3.982.8 Gy and they are usually less than the applied dose by an average factor of 0.22 and 3.3 Gy respectively, also there is a linear proportional and significant (R2 = 0.9) relationship between the applied dose and the measured OD at entrance and exit side of the phantom that could be fitted in the following equation y = 0.040x + 0.117 and y = 0.031x + 0.099 respectively, where x refers to the applied dose and y refers to the OD at the entrance and exit sides of the phantom. Also there is a linear proportional and significant (R2 = 0.9) relationship between the entranceexit doses measured by TLD and the relative OD at both sides of the phantom which could be fitted in the following equation y = 0.035x + 0.159 and y = 0.027x + 0.132 respectively, where x refers to the entranceexit doses and y refers to the entranceexit OD and the attenuation coefficient of Perspex (phantom) has been derived correctly from the relationship between the phantom thickness and its absorption coefficient which was 0.1670 cm-1.