Abstract : The current research focuses on simulation of image reconstruction of polypropylene (PP) with rebars by filtered back projection algorithm using PHITS and MATLAB program. Linear attenuation coefficients () and mass attenuation coefficients (m) were investigated in the photon energies of 0.03 to 20 MeV. particle and heavy ion transport code system (PHITS) was used with gamma radiation narrow beam transmission technique. Simulation measurements were carried out by NaI (Tl) detector and Cs-137 source. Firstly, pure polypropylene block was carried out with PHITS simulation. Secondly, standard phantom of cylindrical polypropylene with 5 cm diameters of two holes was studied according to IAEA TECDOC series. Thirdly, the samples of polypropylene block containing one steel bar and two steel bars with different diameters were also tested. These phantoms were scanned with 6 intervals over 0 to 180 in PHITS simulation and measured with moving of center to center detector spacing of 0.5 cm, 1.0 cm and 1.5 cm, respectively. The most popular methods in image reconstruction is filtered back projection (FBP) algorithm. The results indicated that the images of the phantoms in image reconstruction were seen clearly at 0.5 cm distance of spacing. Performance improvements in MATLAB were investigated. It was found that spline and without filter were the best functions for the clearest image of polypropylene for both two holes, and one bar and two bars. Therefore, the obtained images indicated that FBP algorithm used in MATLAB can be substantial for various applications in the field of medicine and industry

Keyword : Attenuation Coefficients, Filtered Back Projections, Image Reconstruction, Polypropylene