SimITK/SimVTK environment is developed for image analysis, visualization, and image-guided surgery.SimITK/VTK is an implementation of the ITK and VTK C++ libraries in MATLAB, specifically the Simulink visual programming environment.The advantage to this visual programming approach, compared to scripting or C++ applications, are short development times and high maintailabilty due to the existence of pre-built SimITK/VTK models.SimITK/VTK also generates the Simulink blocks directly from the library source files via custom-written automated processes specifically tailored to each library. This ensures that the final blocks parallel their written-code equivalents.The main interest of this project is image-guided therapy. To support this, SimVTK blocks are available for surgical tracking devices and ultrasound video acquisition.