Biopsy site marker for limited migration

A biopsy site marker, comprising:

• (a) a carrier, the carrier including:
• (i) an inner carrier portion defining a proximal end and a distal end,
• (ii) a pair of outer carrier portions, each outer carrier portion being disposed on the proximal end and the distal end of the inner carrier portion, respectively,
• (iii) a first interface disposed between the proximal end of the inner carrier portion and the corresponding outer carrier portion, and
• (iv) a second interface disposed between the distal end of the inner carrier portion and the corresponding outer carrier portion;
• and
• (b) a marker element extending from the inner carrier portion to at least one of the outer carrier portions,
• the pair of outer carrier portions both including a first marker material, wherein the first marker material of each outer carrier portion extends continuously from corresponding first and second interfaces to respective terminal ends of the carrier, the inner carrier portion including a second marker material extending from the proximal end to the distal end, wherein the marker element is disposed in the second marker material, the first marker material being configured to expand at a rapid rate relative to the second marker material in a presence of moisture;
• and
• the first interface and the second interface both being configured to restrict a diameter of each outer carrier portion near the first interface and the second interface, respectively.

A biopsy site marker, comprising:

• (a) a carrier defining a proximal-most end and a distal-most end, the carrier including:
• (i) an inner carrier portion defining a proximal end and a distal end,
• (ii) a proximal outer carrier portion,
• (iii) a distal outer carrier portion, the distal outer carrier portion and the proximal outer carrier portion being disposed on the distal end and the proximal end of the inner carrier portion, respectively,
• (iv) a first interface disposed between the proximal end of the inner carrier portion and the proximal outer carrier portion, and
• (v) a second interface disposed between the distal end of the inner carrier portion and the distal outer carrier portion;
• and
• (b) a marker element disposed within the carrier,
• the proximal outer carrier portion including a first marker material extending from the proximal-most end to the first interface and the distal outer carrier portion including the first marker material extending from the distal-most end to the second interface, the inner carrier portion including a second marker material extending from the first interface to the second interface, the first marker material being configured to expand at a rapid rate relative to the second marker material in a presence of moisture;
• and
• the first interface and the second interface both being configured to locally restrict a size of the proximal outer carrier portion and the distal outer carrier portion near the first interface and the second interface, respectively.