Hydroxyapatite Tissue Marker for Multi-Modality Imaging

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Solution Overview

Problem

Existing tissue markers are not visible under all available imaging modalities, making it difficult to locate tumors for treatment, especially after tumor shrinkage or in cases where visualization depends on breast tissue positioning.

Innovation Solution

A biocompatible biopsy marker made of hydroxyapatite or porous metal/ceramic materials, with voids filled with biocompatible gas for ultrasonic visibility and a coating to prevent fluid ingress, ensuring visibility under multiple imaging modalities and biodegradability options.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a marker is designed to be visible under X-ray imaging, then X-ray visibility is improved, but visibility under ultrasonic imaging may be compromised

Engineering Contradiction:
Improveimaging modality visibilityVSAvoidvisualization reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The marker combines multiple materials with different imaging properties: a radiopaque material (such as metal or ceramic) provides X-ray visibility, while gas-filled pores provide ultrasonic visibility through acoustic impedance contrast. This composite structure allows simultaneous optimization for multiple imaging modalities without compromising either capability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The marker incorporates porous structures with gas-filled pores that create strong acoustic impedance contrast for ultrasonic imaging. The porous architecture also allows the marker to be biocompatible and potentially bioabsorbable, while the gas pockets maintain ultrasonic visibility throughout the degradation process.

Inventive Principle:
Principle #31Porous materials

2Object-affected harmful factors

If a marker is made of biocompatible biodegradable material, then biocompatibility is improved, but durability and visibility stability may worsen

Engineering Contradiction:
ImprovebiocompatibilityVSAvoidmarker durability
Core Design Contradiction:
Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The marker uses porous biocompatible materials such as hydroxyapatite or porous metal/ceramic that are inherently biocompatible and potentially bioabsorbable. The porous structure provides both biocompatibility and acoustic contrast for ultrasonic imaging, while the material properties can be tuned to achieve desired degradation rates.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The marker combines biocompatible biodegradable materials with radiopaque and ultrasonic contrast materials. The composite structure allows the biocompatible matrix to provide biological compatibility while the embedded radiopaque and gas-filled pores maintain imaging visibility and structural integrity throughout the marker's service life.

Inventive Principle:
Principle #40Composite materials

3Reliability

If tumor shrinkage is achieved through chemotherapy or irradiation, then treatment effectiveness is improved, but tumor locateability worsens

Engineering Contradiction:
Improvetreatment effectivenessVSAvoidtumor locateability
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The marker is placed at the tumor site during biopsy as a preliminary action to establish a permanent, visible reference point. This pre-positioned marker remains stable even as the tumor shrinks due to treatment, providing a reliable landmark that maintains its visibility and location accuracy throughout the treatment process and into post-treatment follow-up.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The marker utilizes contrast mechanisms that create distinct visual signatures under different imaging modalities. The radiopaque material provides X-ray contrast while the gas-filled pores provide ultrasonic contrast, creating a multi-modal visible marker that stands out clearly against surrounding tissue regardless of tumor size changes.

Inventive Principle:
Principle #32Color changes

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 markers provide clear visualization under X-ray and ultrasonic imaging, reducing the need for multiple procedures and enhancing biocompatibility, while allowing for selectable bioabsorbability.

Implementation Method 1

The biopsy site markers have high ultrasound reflectivity due to high contrast of acoustic impedance resulting from gas-filled internal pores

Methodology Applied
Scientific EffectAcoustic impedance contrast: Ultrasound

Implementation Method 2

The markers are visible under a variety of imaging modalities including X-ray and ultrasonic imaging

Methodology Applied
Scientific EffectX-ray absorption: X-Ray

Data Source

PatentEP3542748B1Multiple imaging mode tissue marker
Publication Date: 2023.08.16 CR BARD INC
  • EP3542748B1 patent drawingFigure 1~7

AI summary

An intracorporeal marker for marking a site within living tissue of a host having a body of porous hydroxyapatite whose physical properties permit the body to be distinguished from human soft tissue under visualization using ultrasonic and radiation imaging modalities.