An implantable fiducial marker having a sealed cavity for the introduction of an imaging agent that provides imaging capability in several modes, including Computed Tomographic imaging (CT) and Magnetic Resonance Imaging (MRI) is disclosed. The marker may be permanent, or it may be temporary and readily...http://www.google.de/patents/US20010004395?utm_source=gb-gplus-sharePatent US20010004395 - Fiducial marker
