Contrast-Loaded Microbeads for SIRT Shunt Fraction Mapping
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Solution Overview
Problem
Existing SIRT treatments face challenges in determining the quantity of microbeads that shunt or migrate to non-targeted tissues, necessitating separate pre-treatment mapping sessions with biodegradable radioactive microbeads and coordinating scheduling of angiography and nuclear imaging resources, which is logistically difficult and time-critical.
Innovation Solution
A method using X-ray imaging of biodegradable microbeads with different contrast materials to estimate microbead concentration and distribution in target tissue, allowing for dosimetric calculations without the need for separate nuclear imaging, and enabling easier logistics by using only a CBCT or Angio-CT room.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate pre-treatment mapping session with biodegradable radioactive microbeads is performed, then shunt fraction can be determined, but logistical complexity and scheduling difficulty increase
Solution Approach 1:
The patent combines the mapping function and treatment function into a single injection procedure. Non-radioactive contrast-loaded microbeads are used to perform both the shunt fraction determination (mapping) and the treatment in one session, eliminating the need for separate pre-treatment mapping sessions with radioactive MAA beads and coordinating multiple imaging resources.
Solution Approach 2:
The patent uses non-radioactive contrast-loaded microbeads instead of radioactive MAA beads. These non-radioactive microbeads can be stored at room temperature or in a refrigerator for extended periods without the time-critical ordering constraints of radioactive materials, simplifying logistics while maintaining the ability to determine shunt fraction accurately.
2Loss of information
If separate pre-treatment mapping session is scheduled, then shunt information is obtained, but time consumption and scheduling difficulty increase
Solution Approach 1:
The mapping and treatment procedures are merged into a single session. The non-radioactive contrast-loaded microbeads serve dual purposes: they enable shunt fraction determination through X-ray/CT imaging and simultaneously provide the treatment effect, thereby obtaining shunt information without requiring separate scheduling of pre-treatment mapping sessions.
Solution Approach 2:
Non-radioactive contrast-loaded microbeads serve as an intermediary that enables both mapping and treatment functions. These microbeads allow visualization through X-ray/CT imaging (providing mapping information) while also delivering the therapeutic effect, thus obtaining shunt information without the time loss associated with separate radioactive bead ordering and imaging scheduling.
3Measurement precision
If radioactive MAA microbeads are used for mapping, then shunt detection is possible, but time-critical preordering and storage constraints arise
Solution Approach 1:
The patent replaces radioactive MAA beads with non-radioactive contrast-loaded microbeads. These non-radioactive microbeads do not have time-critical ordering constraints or limited half-life requirements. They can be stored at room temperature or in a refrigerator for extended periods while maintaining stability, eliminating the logistical burden of time-critical preordering associated with radioactive materials.
Solution Approach 2:
The patent changes the detection parameter from radioactive emission detection (SPECT/CT) to X-ray/CT density-based detection. This parameter change allows the use of non-radioactive contrast-loaded microbeads that can be stored long-term without degradation, removing the constraint of radioactive half-life time while maintaining the ability to detect shunt fraction through imaging.
4Loss of information
If SPECT/CT or PET/CT imaging is used for mapping, then radioactive microbead distribution is visualized, but resource coordination complexity increases
Solution Approach 1:
The patent introduces non-radioactive contrast-loaded microbeads as an intermediary that enables visualization through conventional X-ray/CT imaging. This intermediary approach allows obtaining microbead distribution information without requiring coordination of specialized nuclear imaging resources (SPECT/CT or PET/CT), as X-ray/CT is more widely available and does not require the same level of resource coordination.
Solution Approach 2:
The patent uses conventional X-ray/CT imaging which serves multiple functions: it can visualize the contrast-loaded microbeads for shunt fraction determination, and it is a more universally available modality compared to specialized nuclear imaging. This multi-functionality reduces the complexity of coordinating specialized imaging resources while still providing the necessary microbead distribution information.
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
Facilitates accurate determination of shunt fractions without requiring separate nuclear imaging, reducing logistical complexity and time-critical ordering of radioactive materials, while maintaining stability for several months.
Implementation Method 1
X-Ray images of tissue including microbeads are used to estimate the microbead concentration and distribution in target tissue of interest
Implementation Method 2
Known spectral X-ray imaging approaches of material separation between multiple contrast agents for photon counting CT/CBCT or dual energy CT/CBCT are used in the disclosed method
Data Source
AI summary
A method includes determining a shunt fraction of microbeads by comparing a known ratio of a mixture of smaller microbeads loaded with a first contrast agent to larger microbeads loaded with a second contrast agent changes to a diffused ratio of the smaller microbeads to the larger microbeads after the mixture has been administered to a treatment site.