Two main view modes allow the users to interact with the system. One view, the AR view, offers an overview of the surgical site to the user, by projecting the 3D reconstruction on the video image of the body. The second view, or VR view, is a purely virtual visualization of the 3D reconstructed radiation distribution from the view of the gamma probe, without visual reference to the anatomy. The separate view modes, including their appearance and motivation are presented in more detail in section 2.3.