US Patent 8401622 Biopsy marker with in situ-generated imaging properties

A biopsy marker having radio-opaque properties that are derived in situ, based on a natural a biological response, such as for example, calcification, accumulation or tissue-concentration of a chemical agent so as to provide an imaging contrast. A biodegradable foam such as collagen foam or gelatin foam is embedded with a biological tissue that is susceptible to the calcification. Initially the marker can be imaged using ultrasound, but over time, the embedded material calcifies causing it to become visible under radiation imaging.