Needle Positioning Apparatus Using Mechanical Stopper
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Solution Overview
Problem
Current positioning systems for percutaneous puncture therapies, which rely on medical images like MRI or CT, face challenges in achieving high precision due to the complexity of absolute encoders and potential magnetic interference, leading to inaccuracies and increased surgeon burden.
Innovation Solution
A positioning apparatus with a guide for needle-shaped medical equipment, incorporating a rotation unit, detector, position measuring unit, contact portion, stopper, and setting unit to simplify the positioning process while ensuring accuracy, using incremental encoders and a stopper mechanism to regulate rotation and detect precise positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an absolute encoder is used to detect absolute position, then positioning precision is improved, but device complexity and signal processing requirements increase
Solution Approach 1:
The patent replaces the absolute encoder (electromagnetic/optical system) with a mechanical stopper mechanism combined with an incremental encoder. The stopper provides mechanical reference positioning, while the incremental encoder tracks position changes from this reference point, avoiding the complex absolute position detection requirements.
Solution Approach 2:
The patent introduces a stopper as an intermediary mechanical element that provides a reference position. The incremental encoder then measures position relative to this reference, serving as a mediator between the mechanical positioning system and the digital measurement system, simplifying the overall complexity.
2Measurement precision
If an absolute encoder is used in MRI environment, then positioning accuracy is improved, but magnetic interference affects reliability
Solution Approach 1:
The patent replaces electromagnetic absolute encoders with a mechanical stopper mechanism and incremental encoder system. This mechanical approach is immune to MRI magnetic field interference, ensuring reliable operation in the magnetic environment while maintaining positioning accuracy through the reference-based measurement approach.
3Measurement precision
If circuit scale is increased for absolute encoder, then positioning precision is improved, but magnetic distortion increases
Solution Approach 1:
The patent eliminates the need for large-scale electromagnetic circuits by using a mechanical stopper with an incremental encoder. This mechanical solution achieves positioning precision without introducing magnetic distortion, as it does not rely on electromagnetic fields that would be distorted by the MRI magnet.
4Ease of operation
If visual scale is used for puncture direction, then ease of operation is improved, but positioning precision is limited
Solution Approach 1:
The patent implements feedback by using the stopper to provide a definite reference position and the incremental encoder to accurately track position changes from this reference. This feedback mechanism allows the surgeon to easily operate the puncture device while the system automatically maintains precise positioning information.
Solution Approach 2:
The patent creates a digital copy of the mechanical position through the incremental encoder, which tracks position changes from the stopper reference. This digital representation provides precise positioning data without requiring the surgeon to directly read or interpret fine visual scales.
Data Source
AI summary
A positioning apparatus includes a needle guide, a rotation unit, a detector for the rotation position, a position measuring unit, an engageable stopper, and a setting unit for setting position information to a value corresponding to a predetermined position are provided herewith. The positioning apparatus can be used, for example, to position a needle placement manipulator.