Apparatus and methods are described for deploying an implantable tool at an implantation location of a blood vessel. The tool is placed at the implantation location in a non-deployed configuration. A plurality of image frames are acquired of the non-deployed tool at the implantation location, during respective phases of the vessels motion cycle. A stabilized image stream is generated of the non-deployed tool at the implantation location. It is determined based upon the stabilized image stream of the non-deployed tool that, during the vessels motion cycle, the tool moves from the implantation location by a given distance in a first direction. Movement of the tool by the given distance is accounted for, by deploying the tool at a deployment location that is distant from the implantation location in the opposite direction to the first direction. Other embodiments are also described.