US Patent 9795455 Tissue marker for multimodality radiographic imaging

A radiographic marker containing a sensing medium that initially includes a gas and liquid mixture for producing increased signal intensity in a first imaging modality. The radiographic marker can have a permeable portion allowing the exchange of the gases or liquids of the sensing medium to be changed or exchanged for at least a second fluid in the surrounding tissue to reduce the bubbles or air pockets created by the gas portion of the sensing medium. The change or exchange of gas for the second liquid in the radiographic marker produces a detectable signal intensity of the radiographic marker in a second imaging modality different from the first imaging modality.