Paper Title
Density Characterization of Radio Chromic Film Through Source Axis Distance (Sad) Techniques in Linac With Slab Phantom for Radiotherapy Applications

Abstract
Characterization of radiochromic film density has been done through Source Axis Distance (SAD) technique on a slab phantom Linac with the variety of wide and depth of field. The Type of the film used is gafchromic RTQA2. The radiation exposure dose of the film may cause changes in the density of the film. This study aims to determine the relationship of density with depth-dose through the characteristic of curves to determine the depth of the dose and the particular breadth field as a reference of the radiotherapy dose patients. The results showed that the higher of dose absorbed, the higher the level of darkness in the film, but the lower of density obtained. Depth dose was determined by measuring the amount of dose received at various depths and wide field uses film that is placed on the slab phantom with 6 MV linac radiation and a dose of 300 cGy. The depth variations of 1.5 cm; 4 cm; 6 cm; 8 cm; 10 cm and the field size of 4x4 cm2, the depth-dose of 359.7 cGy; 315.3 cGy; 281.4 cGy; 241.2 cGy; 220.5 cGy was determined. The field size of 6x6 cm2 depth- dose 354.6 cGy; 314.1 cGy; 282.6 cGy; 244.5 cGy; 224.7 cGy. The field size 8x8 cm2 depth-dose 351.6 cGy; 313 cGy; 283.8 cGy; 247.2 cGy; 228 cGy. The field size 10x10 cm2 depth-dose 348.9 cGy; 342.6 cGy; 248.4 cGy; 249.6 cGy; 231 cGy. Keywords- gafchromic filmRTQA2, SAD, Density, Depth-Dose