Cobalt Contrast Marker for MRI Seed Localization
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Solution Overview
Problem
Current MRI technologies face challenges in accurately localizing titanium radioactive seeds and needle tracks within the prostate during brachytherapy due to negative contrast issues, leading to inaccurate dosimetry and poor quality assurance, which limits the effectiveness of MRI in treatment planning and evaluation.
Innovation Solution
Development of a contrast marker with a novel cobalt-based contrast agent and methodology to modulate signal intensity, allowing for the precise localization of therapy seeds and devices using MRI, enabling accurate dosimetry and improved treatment planning and evaluation in brachytherapy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard titanium radioactive seeds are used for brachytherapy, then the seeds can be implanted for radiation treatment, but the seeds appear as negative contrast on MRI and cannot be accurately localized within the prostate and periprostatic tissue
Solution Approach 1:
The patent combines a titanium radioactive seed with a cobalt-based contrast agent to create a composite seed structure. The titanium seed provides radiation therapy functionality while the cobalt contrast agent provides positive contrast for MRI visualization, resolving the contradiction between therapeutic function and imaging visibility.
Solution Approach 2:
The invention uses composite materials by integrating cobalt-based contrast agent material with the titanium seed structure. This composite approach allows the seed to simultaneously exhibit radiopacity for therapy and positive contrast for MRI imaging, overcoming the limitation of pure titanium seeds that only show negative contrast.
2Illumination intensity
If MRI is used for prostate imaging, then optimal soft tissue contrast is achieved, but the titanium seeds and needle tracks appear as black holes and cannot be accurately localized
Solution Approach 1:
The patent applies the principle of signal intensity change by using cobalt-based contrast agent that produces positive contrast signal on MRI. This changes the appearance of seeds from negative contrast (black holes) to positive contrast (hyperintense signals), enabling accurate localization while preserving optimal soft tissue contrast visualization.
3Measurement precision
If CT imaging is used for seed localization, then positive contrast of seeds is achieved, but the imaging modality is not optimal for prostate soft tissue visualization and dosimetry
Solution Approach 1:
The patent makes MRI multi-functional by enabling it to simultaneously provide optimal soft tissue contrast visualization and accurate seed localization through the cobalt contrast agent. This eliminates the need to switch between CT and MRI modalities, as MRI can perform both functions effectively.
4Measurement precision
If MRI pulse sequences are optimized to identify seeds, then some seeds can be detected, but 12-29% of seeds are still missing which leads to large dose uncertainties
Solution Approach 1:
The patent fundamentally changes the magnetic properties parameter of the seeds by incorporating cobalt-based contrast agent. This parameter change transforms the seeds from being invisible or poorly visible on MRI to being clearly visible with positive contrast, achieving 100% seed detection and eliminating dose uncertainties associated with missing seeds.
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 solution enhances the accuracy of seed placement and dosimetry, improving treatment outcomes and reducing side effects by providing a positive contrast of implanted seeds, thereby optimizing radiation delivery and post-treatment assessment.
Implementation Method 1
MRI is the optimal imaging modality for the prostate and surrounding critical organ structures
Implementation Method 2
a novel contrast agent comprising transition metal complexes, disposed within the casing
Data Source
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AI summary
A contrast marker having a casing and a novel MRI contrast agent comprising metal complexes disposed around, within, or abuting the casing is provided. Such contrast markers may be placed in a strand, with or without a therapy seed, to produce a seeded strand useful for imaging and in connection with brachytherapy.