Tehran University of Medical Sciences Frontiers in Biomedical Technologies 2345-5837 1 2 2014 06 30 138 145 E Toktam Jahanfar Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran AND Research Center of Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran. Sedighe Marjaneh Hejazi Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran AND Research Center of Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran. Amir Homayoun Jafari Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran AND Research Center of Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran. Hanieh Mohammadreza Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran AND Research Center of Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran. 2015 10 13 2015 10 13 Purpose: Optical imaging is established as one of the modalities applied to molecular imaging studies. Molecular imaging can be used to visualization of molecular events in the cellular or sub-cellular level. One of the main goals in optical imaging is giving source distribution. The Forward problem seeks to determine the photon density on the surface of the subject. Among the different methods, Green functions provide a fast method for modeling the diffusion. Green functions are different depending on the source shape, set up and geometry. Methods: In this study, a new optical set up was implemented in the cylindrical geometry. The software is developed and written in MATLAB programming to estimate the intensity on the object’s surface. The algorithm is based on diffusion approximation and evaluated by phantom experiment. Results:The results showed significant correlation coefficients (R>0.9) which demonstrated the high accuracy of the algorithm. Conclusion: We have presented an approximate algorithm that solves the 3D diffusion equation in homogeneous turbid phantom like tissue. The algorithm can be used as part of the reconstruction program using FMT. https://fbt.tums.ac.ir/index.php/fbt/article/view/33 https://fbt.tums.ac.ir/index.php/fbt/article/download/33/32