CT Couch Weight Sensing for Posture-Independent Measurement
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Solution Overview
Problem
Conventional X-ray CT apparatuses face measurement accuracy issues due to moment loads caused by varying subject postures and positions on the table, leading to errors in weight measurement.
Innovation Solution
The X-ray CT apparatus incorporates a table with weight sensors and a processing circuitry that estimates weight based on measurement signals and arrangement information, using calibration information to account for different measurement modes, such as posture and position, thereby improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If weight measurement is performed using a load cell in a conventional CT table, then weight measurement function is provided, but measurement accuracy deteriorates due to moment loads caused by varying subject postures and positions
Solution Approach 1:
The patent divides the weight measurement function into multiple load cells positioned at different locations on the table. Instead of using a single load cell, the system segments the measurement into multiple points (e.g., four load cells at table corners), allowing independent measurement of forces at each position. This segmentation enables the system to account for moment loads by analyzing the distribution of forces across multiple measurement points, thereby maintaining accuracy despite variations in subject posture and position.
Solution Approach 2:
The patent changes the measurement parameters by measuring not only vertical forces but also moment loads (torques) around different axes. By introducing additional measurement parameters (moment values around X-axis and Y-axis) alongside the standard weight measurement, the system can mathematically separate and compensate for the effects of moment loads. This parameter expansion allows accurate weight determination even when subjects are in various postures or positions on the table.
2Measurement precision
If multiple load cells are used to measure moment loads and compensate for posture variations, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the load cell system multi-functional by enabling it to perform both traditional weight measurement and moment load measurement using the same hardware components. The existing load cells are utilized not only for measuring vertical forces (weight) but also for calculating moment loads around different axes through mathematical processing of the force distribution. This universal use of components avoids the need for separate sensors for moment measurement, thereby limiting the increase in device complexity while achieving improved measurement accuracy.
Solution Approach 2:
The patent replaces complex mechanical moment measurement mechanisms with a simplified system based on force distribution analysis. Instead of using dedicated mechanical torque sensors or complex linkage mechanisms to directly measure moments, the system substitutes these with a network of load cells that measure forces, combined with computational algorithms that calculate moment values from the force distribution. This substitution of mechanical complexity with computational processing reduces overall system complexity while maintaining measurement 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 approach ensures accurate weight measurement of subjects regardless of their posture or position, allowing for precise determination of contrast agent dosage and X-ray intensity, and enabling weight measurement during scanning without reducing accuracy.
Implementation Method 1
a measurement unit that outputs a measurement signal corresponding to weight of the subject placed on the table-top
Data Source
AI summary
A medical image diagnostic apparatus according to an embodiment includes a table-top, a measurement unit, and processing circuitry. The table-top places thereon a subject. The measurement unit outputs a measurement signal corresponding to weight of the subject placed on the table-top. The processing circuitry estimates the weight of the subject placed on the table-top, based on the measurement signal and arrangement information on arrangement of the measurement unit.