CT Table Height Offset Calibration for Accurate Isocenter Positioning
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Solution Overview
Problem
Existing CT systems face hospital-specific and location-specific deviations in table height positioning due to variations in cradle pads, accessory shapes, and camera calibration, leading to incorrect manual adjustments by operators.
Innovation Solution
A system that automatically adjusts table height by calculating the center of gravity from medical images, determining positional deviations, and updating offsets based on statistically reliable representative values to ensure precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If automatic positioning is used to move the table, then positioning efficiency is improved, but hospital-specific positional offset in table height is introduced
Solution Approach 1:
The system captures images of the subject body using an attached camera, automatically calculates the position of the imaging location, detects the table height positional offset by comparing actual position with prescribed position, and feeds back this offset information to automatically adjust the table height. This closed-loop feedback mechanism eliminates hospital-specific positional offsets while maintaining automatic positioning efficiency.
Solution Approach 2:
The invention replaces manual mechanical adjustment of table height with an automated optical measurement and calculation system. Instead of relying on manual empirical adjustments, the system uses camera imaging, coordinate transformation, and automated calculations to determine and correct table height positional offsets, thereby improving positioning accuracy while maintaining efficiency.
2Measurement precision
If manual offset adjustment is provided to correct table height positional offset, then positioning accuracy can be improved, but operator workload and potential for incorrect adjustment increases
Solution Approach 1:
The system performs self-service by automatically capturing images, calculating the imaging location position, detecting the table height offset, and adjusting the table height without requiring operator intervention. The offset correction is executed automatically based on calculated values, eliminating the need for operators to manually enter empirical offset values and reducing workload while maintaining high positioning accuracy.
Solution Approach 2:
The invention replaces manual operator adjustment with an automated computational system that uses camera imaging, coordinate system transformations, and algorithmic calculations to determine the correct table height offset. This substitution eliminates human error in manual adjustment while reducing operator workload to simply initiating the automatic process.
3Reliability
If statistical reliability checking is implemented for offset updates, then positioning reliability is improved, but processing time increases
Solution Approach 1:
The system implements statistical reliability checking by calculating the standard deviation of multiple offset measurements and comparing it against a predetermined threshold. Only when the standard deviation falls within the acceptable range (indicating sufficient measurement consistency) does the system proceed with offset updates. This partial action approach ensures reliability through necessary statistical validation while avoiding excessive processing by using efficient threshold-based decision making rather than complex continuous optimization.
Data Source
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AI summary
PROBLEM To provide technology capable of positioning an imaging location at a desired position. [Resolution means] A CT device 100, comprising: a table 116 on which a subject body 112 is placed; and at least one processor; wherein when executing an examination on the subject body 112, the at least one processor executes operations including: driving the table 116 using a table controller 118 that controls the table 116 based on offsets (F1, F2, F3) for correcting positional offset of the table 116 height to position the table 116 at an isocenter 31, obtaining a center of gravity 32 of the imaging location of the subject body in the height direction of the table 116 based on a scout image 17 of the imaging location of the subject body 112, calculating a difference of the isocenter 31 and the center of gravity 32 as a positional deviation d of the table 116 height, and storing the positional deviation d, and the at least one processor further executes operations including: obtaining an average value dave of the positional deviation d, determining whether or not the average value dave of the table 116 positional deviation d is statistically reliable, and updating the offsets based on the average value dave if the average value dave is determined to be statistically reliable.