Expanding Hydrogel Biopsy Site Marker for Migration Control
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Solution Overview
Problem
Existing biopsy site markers are not visible under all imaging modalities and prone to migration, necessitating additional procedures and complicating tumor monitoring during neo adjuvant chemotherapy.
Innovation Solution
Development of a remotely detectable marker comprising a radiopaque element with a distinguishing pattern for x-ray imaging and a non-palpable body that expands to fill the biopsy cavity, providing ultrasound contrast and stability for at least 52 weeks, made from biocompatible materials like PMMA and hydrogel, with features to prevent migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional biopsy site marker is used, then the marker can be implanted at the biopsy site, but the marker is not visible under all imaging modalities (especially ultrasound) and may migrate from the biopsy site
Solution Approach 1:
The marker combines multiple materials with different properties: a radiopaque element (metal or metal alloy) for X-ray visibility, a hydrogel body for ultrasound visibility and tissue compatibility, and a shape memory polymer for controlled deployment. This composite structure enables the marker to be visible under multiple imaging modalities simultaneously while maintaining biocompatibility and preventing migration.
Solution Approach 2:
The marker is divided into distinct functional segments: a radiopaque element segment for mammography visibility, a hydrogel body segment for ultrasound visibility and cavity filling, and a delivery device segment for precise implantation. Each segment performs its specific function, and the segmented structure allows for optimized design of each component.
2Ease of operation
If the breast is released from compression after biopsy, then the breast returns to normal state, but the site marker may migrate within the site or out of the site through the needle tract
Solution Approach 1:
The marker utilizes dynamic shape memory materials that change shape in response to temperature changes. The marker is deployed in a compressed state during the biopsy procedure and then automatically transforms to its expanded stable shape after implantation, ensuring it remains anchored in the biopsy site even when breast compression is released.
Solution Approach 2:
The marker's physical parameters (shape, volume, stiffness) are changed through temperature-dependent shape memory effects. The marker transitions from a compact deployable state to an expanded stable state, and this parameter change ensures the marker remains firmly positioned in the biopsy cavity without migrating when breast compression is released.
3Measurement precision
If additional procedures are performed to place another device at the biopsy site, then the surgeon can locate the biopsy site during surgery, but the patient undergoes additional procedures and experiences increased burden
Solution Approach 1:
The marker is designed to serve multiple functions simultaneously: it provides X-ray visibility for mammography-guided biopsy, ultrasound visibility for intraoperative localization and post-biopsy monitoring, and physical anchoring to prevent migration. This multi-functionality eliminates the need for separate localization devices and procedures.
Solution Approach 2:
The patent merges the functions of multiple separate devices (radiopaque marker for X-ray, ultrasound marker for sonography, and localization device for surgery) into a single integrated marker system. This consolidation reduces the number of procedures needed and simplifies the overall treatment process.
4Duration of action of moving object
If a site marker is used to monitor tumor progression during neo adjuvant chemotherapy, then tumor shrinkage can be tracked, but the marker must remain stable and visible for extended periods (at least 52 weeks)
Solution Approach 1:
The marker is designed to maintain its visibility and positional stability continuously over the extended monitoring period of at least 52 weeks. The hydrogel body provides continuous ultrasound visibility, the radiopaque element provides continuous X-ray visibility, and the shape memory structure ensures continuous positional stability throughout the chemotherapy treatment and tumor regression monitoring process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The marker provides long-term visibility under multiple imaging modalities and minimizes migration, allowing precise lesion localization and monitoring without additional procedures, enhancing treatment accuracy and reducing patient burden.
Implementation Method 1
a radiopaque element having a distinguishing pattern for unique identification under x-ray imaging
Implementation Method 2
the body is comprised of a substantially dehydrated material in a pre-deployment configuration, wherein the body is configured to expand between 5 and 100 percent of its pre-deployment volume in approximately 30 to 60 minutes when exposed to fluid
Implementation Method 3
the body is configured to reflect ultrasound in a way that the body is recognizable as being artificial and is distinguishable from the radiopaque marker
Data Source
AI summary
A biopsy site marker configured to expand upon deployment into a biopsy cavity, and visible under several different imaging modalities, comprises a superabsorbent hydrogel component and a radiopaque element. The hydrogel is in a compressed, dehydrated state prior to deployment to facilitate placement of the marker within the biopsy site, and thereafter expands upon deployment in the biopsy site. Such expansion limits migration of the site marker.