Simulators are medical devices used in the oncology clinics to perform the simulation for the external beam radiotherapy treatment. Unlikely for a clinic to obtain a real Simulator is a high investment in terms of money, space and personnel. The alternative here can be a Virtual Simulator (VS). The CT simulators are system-software that can perform the simulation process using the Computed Tomography (CT) data set of the patient, including the external patient's skin landmarks, instead of the physical patient. In this paper we present a new high performance CT based virtual simulation system running on a low cost widely available PC hardware - EXOMIO. The implemented high-end visualization techniques allow the users to simulate every function of the real simulator including the mechanical component movements, radiation beam projection and fluoroscopy. Further more this virtual simulation concept provides the physicians with ergonomic volume definition and navigation tools. Our clinical experience is described using three patient examples: Neck cancer, prostate cancer and breast cancer. The advantages of virtual simulation system over classical simulation are stated and its clinical effectiveness is emphasized
