Overview of navigation systems in image-guided interventions

With the advent of new imaging technologies, physicians are urged to intervene on targets that are either undetectable previously or have challenging locations. The common practice of "expectant observation" is losing its appeal to many physicians as more and more of the previously "impossible to treat" lesions are within reach of operators. Navigation systems are a wide range of devices with different levels of complexity in design and function that are utilized to help operators to overcome challenges they confront in different clinical scenarios. With the help of these systems, operators can potentially improve clinical outcome of image-guided interventions. We present an overview of navigation in today's medicine and review some of the currently available systems.