Introduction: According to the literature, optical coherence tomography (OCT) can be used measure radiation absorbed dose. This study was carried out to design a computed tomography system for the calculation of absorbed dose and optimization of dose delivery in radiotherapy using gel dosimeters. Material and Methods: An advanced charge-coupled device based OCT system was developed in laboratory with the capability for high resolution three-dimensional (3D) radiation dosimetry using gel dosimeters. The OCT system was compared to magnetic resonance imaging (MRI) as a standard system to investigate its accuracy. Additionally, a number of parameters were checked for assessing the performance of the system. Results: Developing an advanced OCT system, the calibration curve was drawn for OCT and MRI and the received dose values were compared. The amounts of dose obtained from OCT and MRI were 1.98 and 2 Gy respectively with a relative difference of 2%. Conclusion: The quality of treatment can be improved using OCT system in radiotherapy dosimetry.