Radiotherapy forms an essential part in the increase survival and relieve of cancer globally. Tumoricidal dose are delivered to cancerous tumours conformal as practically achievable. Radiation delivery mode, dosimetric verification and quality assurance play a key role in prior to patient treatment. The focus of this study is to present a modality for ensuring good quality control prior to treatment delivery using Cobalt ( 60 Co) source. In the study, absorbed dose to water is computed in a virtual phantom with approximate full scatter conditions with gamma as the radiation source. Monte Carlo Neutron Photon (MCNP) code system was used to simulate the properties of the system geometry of the phantom following the International Atomic Energy Agency (IAEA) Technical Report Series 398 protocol. The research was limited to the use of virtual simulation of water phantom for the Cobalt-60 treatment unit. This work provides information recommended for photon energy according to the medical situation at the radiotherapy facilities in Ghana.