Abstract: A convergent multibeam unit for radiation is disclosed. The unit comprises a lineal accelerator as a radiation means which is angularly displaceable around a virtual axis which intersects the radiation axis of same, said lineal accelerator being combined with a stereotaxic device constituting a frame angularly displaceable around an axis which is substantially normal to the axis of angular displacement of the lineal accelerator and contains the isocenter of same; the angular displacement arches of the radiation axis of said lineal accelerator and of said stereotaxic frame defining a virtual spherical cap in the center of which and coinciding with said isocenter, there is located the area to be radiated on said virtual spherical cap which determines multiple radiation entries converging on said area.

Abstract: An instrument and method for clipping blood vessels are disclosed. The new surgical tool disclosed is particularly adequate to place clips of alpha configuration ending in "V" on brain blood vessels. The invention enables a surgeon to have a free field of vision of the area and the blood vessel to be clipped as well as the clip carried by the instrument.