Minimally invasive spine procedures can spare the patient the trauma associated with open surgery. However, these procedures can be difficult to learn and require extensive training for proficiency. At Georgetown University Medical Center, spine biopsies are often done under computed tomography (CT) guidance. While this technique is effective, it is time consuming since the biopsy needle must be advanced slowly and its position checked several times to ensure vital organs are not damaged. A research project is being conducted to develop a computer-guided, image-based minimally invasive system for therapy and surgical techniques. As an initial step, a needle biopsy simulator for training is being developed. In the next phase, this simulator could also be used for preoperative planning. The simulator consists of two major modules: a visual module to display the medical images and biopsy tools and a haptic module to provide force feedback based on the needle position. The haptic module incorporates a robotic device that provides force feedback in three translational directions. In the future, it is anticipated that semi- autonomous robotic systems, in which the human controls some degrees of freedom and the robot the other degrees of freedom, will be developed for interventional tasks such as needle spine biopsy. The simulator described here can then be used as a 'master arm' to control the robotic system that actually performs the intervention.