Optical Markers for Dynamic Medical Device Calibration
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Solution Overview
Problem
Current medical imaging systems, such as PET/CT scanners, face challenges in maintaining accurate calibration and alignment due to issues like gantry offset changes during maintenance, bed deflection with heavy patients, and the need for calibration in dark environments, which can interfere with certain imaging processes.
Innovation Solution
The implementation of a system using coordinating optical markers and sensors, along with image processing circuitry, to dynamically calibrate the position and orientation of patient transportation mechanisms between medical diagnostic devices, allowing for continuous and accurate alignment of images without the need for pre-stored calibrations or visible light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If pre-stored calibration is used for gantry alignment, then calibration time is reduced, but calibration accuracy deteriorates when gantries are separated and reassembled
Solution Approach 1:
The system transitions from static pre-stored calibration to dynamic real-time calibration using optical markers and sensors. The calibration is performed automatically during each scan session, adapting to any gantry position changes or offsets that occur during operation, thereby maintaining high accuracy without significant time loss.
Solution Approach 2:
The system implements feedback through optical sensors that continuously monitor the position of optical markers on the patient table and gantry. This real-time feedback allows the system to detect and compensate for calibration drift or offset changes, ensuring accurate image fusion without requiring time-consuming manual recalibration.
2Ease of manufacture
If visible light optical markers are used for calibration, then calibration is simple to implement, but functional imaging is interfered with
Solution Approach 1:
The system uses an intermediary approach by employing infrared optical markers and infrared sensors instead of direct visible light. This intermediary wavelength allows calibration to occur without interfering with visible light functional imaging processes, as the infrared calibration signals operate in a different spectral band that does not conflict with PET or other functional imaging modalities.
Solution Approach 2:
The system changes the optical parameter (wavelength) from visible light to infrared for the calibration markers and sensors. This parameter change enables the calibration system to operate in a spectral range that does not interfere with functional imaging, allowing both calibration and imaging to proceed simultaneously without mutual interference.
3Device complexity
If single pre-stored calibration is used, then device complexity is reduced, but measurement precision deteriorates under dynamic bed deflection conditions
Solution Approach 1:
The system employs multiple optical markers distributed along the patient table to capture dynamic bed deflection in real-time. Instead of relying on a single static calibration, the system dynamically tracks the positions of multiple markers to compute accurate transformation parameters that account for bed deflection during scanning, maintaining high measurement precision without excessive complexity.
Solution Approach 2:
The calibration system is segmented into multiple independent optical markers placed at different locations along the patient table. Each marker provides independent position information, allowing the system to segment the overall calibration problem into smaller, manageable measurements that can be processed to account for local bed deflection and maintain precision.
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
This solution enables robust, dynamic calibration and alignment of medical images, ensuring accurate fusion of PET and CT images, even during gantry movement and bed deflection, while accommodating imaging requirements in dark conditions without interfering with functional imaging processes.
Implementation Method 1
at least one optical sensor for detecting the at least one optical marker
Data Source
AI summary
Optical sensors and optical markers are placed on components in a medical system to provide calibration and alignment, such as on a patient transportation mechanism and spatially separated medical diagnostic devices. Image processing circuitry uses the data captured by these optical devices to coordinate their movements and/or position. This enables scans that were captured in multiple medical diagnostic devices to be accurately aligned.