Non-Invasive Input Function Determination for Molecular Imaging
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Solution Overview
Problem
Current methods for determining pharmacokinetic and pharmacodynamic data in molecular imaging are cumbersome, requiring prolonged patient scanning and invasive blood sampling, which are inconvenient and prone to errors due to the diffusion of tracers into red blood cells during sampling.
Innovation Solution
A system and method for determining an input function from an organ with high blood volume using imaging data, allowing for repeated normalization of tracer uptake and circulation, eliminating the need for blood sampling by deriving the input function directly from images, and incorporating patient-specific information like hematocrit into models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive blood sampling is used to determine input function, then measurement precision may be improved, but device complexity and ease of operation deteriorate due to invasive procedures and tracer diffusion into red blood cells
Solution Approach 1:
The patent extracts the input function determination from invasive blood sampling and relocates it to non-invasive image-based measurement. By deriving the input function directly from imaging data of organs with high blood volume (heart, aorta, pulmonary artery), the method eliminates the need for invasive procedures while maintaining measurement capability.
Solution Approach 2:
The patent introduces imaging data as an intermediary between the tracer and the measurement process. Instead of directly sampling blood, the system uses images of blood-containing organs as a mediator to derive the input function, avoiding direct blood contact and tracer diffusion issues.
2Measurement precision
If prolonged scanning (60-90 minutes) is performed to acquire PK/PD data, then measurement precision is improved, but loss of time and productivity deteriorate
Solution Approach 1:
The patent performs preliminary determination of the input function from imaging data before proceeding with full PK/PD analysis. By establishing the input function early from image-based measurements, the method prepares necessary parameters in advance, enabling more efficient subsequent analysis and reducing total scanning time.
Solution Approach 2:
The patent uses partial information from images of organs with high blood volume to derive the complete input function. Instead of requiring full blood sampling over time, the method extracts sufficient data from selective organ imaging to reconstruct the input function, reducing the overall measurement burden.
3Measurement precision
If repeated blood sampling is performed to account for tracer diffusion, then measurement precision is improved, but device complexity and ease of operation worsen due to increased sampling frequency
Solution Approach 1:
The patent removes the complex repeated sampling requirement by extracting input function information directly from images. The method eliminates the need for multiple blood draws and the associated complexity of managing frequent sampling schedules and handling.
Solution Approach 2:
The imaging system itself provides the input function data without requiring external blood sampling interventions. The organs with high blood volume serve as self-contained sources of input function information, eliminating the need for separate sampling procedures.
Data Source
AI summary
Methods and systems for controlled administration of a tracer and quantification of uptake of the tracer by a target organ are described. The method includes administering a tracer to a patient and imaging at least two regions of the patient's body that cannot be imaged simultaneously. An input function for the tracer can be determined by imaging a first region of the patient's body during selected times, and using an injector to administer the tracer in a manner that accurately estimates the input function when this first region is not being imaged. One or more additional regions of the body may then be imaged to create data that may be used to estimate the input function. One or more parameters may then be estimated from each additional region of the body based on the input function and the imaging data gathered from each region.