Patent ID: 8463357

Claim:
An interstitial marker configured to be imaged when inserted into soft tissue of an organ, tumor or tumor bed within a mammalian body, the marker having a longitudinal length and rings made of a non-radioactive wire, the rings being held in spaced relation along the longitudinal length of the marker, the longitudinal length of the marker longer than an outer diameter of the rings, the marker configured for insertion into soft tissue inside the body and held by the soft tissue, the marker configured to be substantially straight just after insertion inside the soft tissue, the rings having an outer diameter of from about 25 μm to about 2500 μm, a ratio of length of the marker to outer diameter of the rings of 10 or more and the rings comprising a wire having a cross section length of from about 10 μm to about 2500 μm, wherein the longitudinal length of the marker, wire cross section length, outer diameter of the rings, and ratio of longitudinal length of the marker to the outer diameter of the rings are effective to make the marker visible under at least one imaging modality selected from the group consisting of x-ray, radiography, CT scan, ultrasonography, and fluoroscopy, and wherein the longitudinal length of the marker, wire cross section length, outer diameter of the rings and ratio of longitudinal length of the marker to the outer diameter of the rings also are effective for flexibility transverse to the longitudinal length of the marker and which flexibility is effective to permit the marker to be responsive to changes of shape of the organ, tumor or tumor bed and to follow movements of the organ, tumor, or tumor bed after insertion as a substantially straight marker, but after at least one of treatment, natural growth or stresses from the soft tissue while implanted in the mammalian body; and wherein the rings are separated by a distance along the longitudinal length of the marker, and a ratio of wire cross section length to the separation distance of the rings is about 1:1.2± about 0.2, the separation distance, the marker longitudinal length, the wire cross section length, the outer diameter of the rings, the ratio of longitudinal length to outer diameter of the rings effective for providing lateral flexibility transverse to the longitudinal length of the marker.