Paramount to the success of image guided interventional procedures is accurate device placement at the target of interest. This requires the operator to plan needle or probe trajectories and execute their placement utilizing real time or intermittent image guidance. Conventional imaging modalities used for interventional guidance include ultrasound, computed tomography, or fluoroscopy. Each modality possesses benefits as well as limitations1. Ultrasound offers real time guidance and the freedom of needle positioning and angulation without imparting radiation to the patient or operator. On the other hand, ultrasound may not be able to visualize deep lesions or those obscured by lung, bone or bowel. Fluoroscopy also has the benefit of real time imaging but lacks the soft tissue detail afforded by cross sectional imaging. Interventional CT units provide better visualization of deep visceral or lung lesions but impart radiation to the patient and operator, restrict device manipulation within the gantry and only allow for fixed 2-dimensional imaging. For those targets seen on prior MRI or PET/CT, but not readily seen or accessible using ultrasound, fluoroscopy or interventional CT, the operator must rely on estimations of target location based upon landmarks and mental registration/correlation. Multimodality image fusion techniques aim to mitigate these limitations and eliminate the need for mental triangulation by combining the strengths of complementary imaging modalities in the same procedural session. This can be accomplished by co-registering different imaging modalities as a superimposed data set or displaying two co-registered data sets side-by-side. This allows the operator to visualize the size and shape of a lesion, the surrounding structures as well as optimize needle trajectory. Image fusion allows the operator to leverage the benefits of both cross-sectional imaging and real time guidance e.g. with ultrasound or fluoroscopy, while obviating the need for the physical presence of a CT, MRI or PET/CT scanner in order to perform the procedure. Image fusion can facilitate targeting of lesions that might be difficult or impossible to target with either single modality alone, and has the potential to reduce procedure time, procedural complications and radiation dose2.