A biopsy site marker having at least one small marker body or pellet of bioresorbable material such as gelatin, collagen, polylactic acid, polyglycolic acid which has a radiopaque object, preferably with a non-biological configuration. The at least one bioresorbable body or pellet with a radiopaque object is deposited into the biopsy site, by an delivery device that includes an elongated tubular body with a piston slidable within the tubular body. One end of the tube is placed into the biopsy site. At least one but preferably several marker bodies or pellets are deposited sequentially into the biopsy site through the tube. At least the bioresorbable materials of the detectable markers remain present in sufficient quantity to permit detection and location of the biopsy site at a first time point (e.g., 2 weeks) after introduction but clear from the biopsy site or otherwise do not interfere with imaging of tissues adjacent the biopsy site at a second time point (e.g., 5-7 months) after introduction.

Imageable biopsy site marker

The invention is directed biopsy site markers and methods of marking a biopsy site, so that the location of the biopsy cavity is readily visible by conventional imaging methods, particularly by ultrasonic imaging. The biopsy site markers of the invention have high ultrasound reflectivity, presenting a substantial acoustic signature from a small marker, so as to avoid obscuring diagnostic tissue features in subsequent imaging studies, and can be readily distinguished from biological features. The several disclosed embodiments of the biopsy site marker of the invention have a high contrast of acoustic impedance as placed in a tissue site, so as to efficiently reflect and scatter ultrasonic energy, and preferably include gas-filled internal pores. The markers may have a non-uniform surface contour to enhance the acoustic signature. The markers have a characteristic form which is recognizably artificial during medical imaging. The biopsy site marker may be accurately fixed to the biopsy site so as to resist migration from the biopsy cavity when a placement instrument is withdrawn, and when the marked tissue is subsequently moved or manipulated.

Tissue site markers for in vivo imaging

Detectable markers that may be introduced into a cavity created by removal of a biopsy specimen to mark the location of the biopsy site so that it may be located in a subsequent medical/surgical procedure. The markers remain present in sufficient quantity to permit detection and location of the biopsy site at a first time point (e.g., 2 weeks) after introduction but clear from the biopsy site or otherwise not interfere with imaging of tissues adjacent the biopsy site at a second time point (e.g., 5-7 months) after introduction.

Methods and chemical preparations for time-limited marking of biopsy sites

A biopsy localization device made according to the invention includes a bioabsorbable element (34), such as a dehydrated collagen plug, delivered in a pre-delivery state to a soft tissue biopsy site (18) of a patient by an element delivery device (32). The bioabsorbable element preferably swells to fill the biopsied open region (26) and preferably is palpably harder than the surrounding soft tissue at the biopsy site. The bioabsorbable element permits the biopsy site to be relocated by palpation to eliminate the need to use metallic clips during biopsies and often eliminates the need for a return to the radiologist for pre-operative localization. In addition, the bioabsorbable element can be used as a therapeutic tool for treatment of the diseased lesion and for hemostatis.

Biopsy localization method and device

The bioabsorbable implant described has a porous body formed of bioabsorbable materials that have an in vivo life span of at least 2 weeks, preferably at least three weeks and not greater than 20 weeks, preferably no greater than ten weeks. The implant has a scaffolding structure which facilitates tissue in-growth and ultimately tissue replacement of the scaffolding structure. The implant has a radiopaque imaging agent at least at the exterior margins and an orientation plurality of radiopaque elements in the interior of implant. The implant preferably has three radiopaque elements within the interior that form a plane within the implant interior.

Porous bioabsorbable implant

A system for remotely inducing a phase transition in a gel is provided. The system includes a gel capable of volume change in response to an environmental stimulus, a seed material in contact with the gel, and generating a time-varying magnetic or a time-varying electric or electromagnetic field in the proximity of the gel to produce the environmental stimulus. In a preferred embodiment, the environmental stimulus is temperature.

Xiaohong Yu

Papers

Electromagnetically triggered, responsive gel based drug delivery device