Implantable Dissolved Oxygen Sensor Using MR Contrast Agent
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Solution Overview
Problem
Current methods for measuring intratumoral dissolved oxygen levels are invasive, limited to superficial tumors, and lack the ability for repeated, non-invasive monitoring, which is essential for effective treatment planning and patient outcomes.
Innovation Solution
An implantable sensor using a magnetic resonance (MR) contrast agent for oxygen, integrated with an oxygen-permeable material, allows for repeated measurements of dissolved oxygen concentrations in vivo through MR-based methods, providing higher sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive needle electrodes are used for oxygen measurement, then measurement precision is improved, but patient discomfort and invasiveness increase
Solution Approach 1:
The patent replaces the mechanical needle electrode system with an implantable sensor that uses magnetic resonance (MR) contrast agents. The sensor contains oxygen-sensitive paramagnetic materials that alter MR signal characteristics in response to oxygen concentration changes, eliminating the need for invasive needle insertion while maintaining measurement capability through non-invasive MRI scanning.
Solution Approach 2:
The patent introduces an intermediary substance - an oxygen-sensitive MR contrast agent - that mediates between the oxygen environment and the detection system. The contrast agent (such as perfluorocarbon or paramagnetic compounds) interacts with oxygen molecules and modulates MR signal properties, allowing indirect but accurate oxygen measurement without direct electrode-tissue contact.
2Productivity
If repeated invasive measurements are performed, then real-time monitoring capability is improved, but patient discomfort and measurement invasiveness increase
Solution Approach 1:
The implantable sensor with MR contrast agent enables repeated measurements by replacing the invasive needle procedure with a non-invasive MRI-based detection system. The sensor remains implanted and continuously monitors oxygen levels, with data retrieved through external MRI scanners, allowing frequent monitoring without repeated patient trauma.
Solution Approach 2:
The implantable sensor performs self-monitoring of oxygen levels continuously once implanted. The oxygen-sensitive contrast agent automatically responds to changes in the local oxygen environment, and the sensor maintains its function without requiring external intervention or repeated insertion procedures.
3Object-affected harmful factors
If non-invasive methods with contrast agents are used, then patient discomfort is reduced, but measurement precision and reliability decrease
Solution Approach 1:
The patent uses oxygen-sensitive MR contrast agents (such as perfluorocarbons or paramagnetic compounds like gadolinium chelates) as intermediaries that provide precise oxygen concentration information through their characteristic MR signal properties. These contrast agents have well-defined relaxation times that vary predictably with oxygen partial pressure, enabling accurate quantification.
Solution Approach 2:
The patent exploits changes in MR signal parameters (specifically T1 and T2 relaxation times) in response to oxygen concentration variations. The oxygen-sensitive contrast agent exhibits parameter changes in its MR signal characteristics that directly correlate with oxygen levels, allowing precise measurement through non-invasive MRI scanning.
4Measurement precision
If implantable sensors with MR contrast agents are used, then measurement precision and repeated monitoring capability are improved, but device complexity increases
Solution Approach 1:
The implantable sensor employs thin-film encapsulation and flexible encapsulating layers to contain the oxygen-sensitive MR contrast agent. These thin films provide a barrier that maintains the integrity of the contrast agent while allowing oxygen diffusion, creating a simple yet effective sensor structure that can be implanted without complex mechanical components.
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
Enables non-invasive, repeated monitoring of dissolved oxygen levels at specific tissue sites, improving treatment planning and patient outcomes by providing real-time data on hypoxia and metabolic activities without patient discomfort.
Implementation Method 1
an oxygen-permeable membrane covering the reservoir opening
Implementation Method 2
The sensing medium comprises an MR contrast agent for oxygen
Data Source
AI summary
A sensor is provided for measuring a dissolved oxygen concentration in vivo when implanted at a tissue site and in ex vivo applications. The sensor includes an article comprising a sensing medium retained within the implantable article by an oxygen-permeable material. The sensing medium comprises an MR contrast agent for oxygen. The sensor is configured to indicate the dissolved oxygen concentration of a fluid, e.g., in vivo at the tissue site, when subjected to an MR-based method.