Compact Needle Manipulator for MRI-Guided Prostate Interventions
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Solution Overview
Problem
Current robotic manipulators lack the dexterity and power required to accurately deliver needles within the confined space of MRI instruments during prostate cancer treatments, leading to challenges in tumor localization and treatment efficacy.
Innovation Solution
A robotic manipulator system with a translational carriage propelled by a linear motor, a shoulder yaw joint actuated by a shoulder yaw motor, and a yaw-pitch-roll wrist mechanism, allowing for precise control and movement of a needle-based instrument within the MRI bore, enabling accurate needle placement and treatment delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air-powered, ultrasonic, or piezoelectric robots are used, then the manipulator can operate within MRI environment, but the dexterity and power are insufficient
Solution Approach 1:
The patent replaces traditional mechanical drive systems with magnetic coupling mechanisms. External magnets on the manipulator arms interact with internal magnets in the MRI bore, enabling mechanical actuation without direct contact. This substitution allows the system to maintain mechanical dexterity and power while operating within the MRI environment, resolving the contradiction between MRI compatibility and operational capability.
2Volume of moving object
If a compact manipulator is designed for MRI bore, then the space constraint is satisfied, but the range of motion and positioning precision are limited
Solution Approach 1:
The manipulator is divided into multiple independent arms (first manipulator arm, second manipulator arm) that can move and position separately. Each arm can be independently controlled to achieve precise positioning at the target location within the MRI bore. This segmentation allows the compact structure to maintain high positioning precision by coordinating the motion of multiple smaller components rather than relying on a single large mechanism.
Solution Approach 2:
The patent introduces a needle holder as an intermediary component between the manipulator arms and the needle. The needle holder provides a stable mounting point and allows for precise angular adjustment and positioning of the needle. This intermediary mechanism enables accurate needle placement while keeping the manipulator arms compact, as the precision is achieved through the specialized needle holder design rather than requiring excessively long or complex arm structures.
3Ease of operation
If multiple manipulator arms are used to improve dexterity, then the positioning capability is enhanced, but the device complexity increases
Solution Approach 1:
The manipulator arms are designed with universal joints and magnetic coupling mechanisms that allow them to perform multiple functions: positioning, orienting, and stabilizing the needle. Each arm can independently execute these functions, and they can work in coordination. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in device complexity despite having multiple arms. The same structural elements serve multiple purposes across different operational phases.
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
The system provides enhanced precision and power for needle placement, improving tumor localization and treatment efficacy while maintaining sterility and compatibility with MRI environments.
Implementation Method 1
a translational carriage coupled to ride along the track, the translational carriage being propelled along the track by a linear motor
Implementation Method 2
a shoulder yaw joint coupled to the translational carriage, the shoulder yaw joint being actuated by a shoulder yaw motor
Implementation Method 3
a shoulder pitch joint coupled to the shoulder yaw joint, the shoulder pitch joint including an arm, a wrist mount coupled to the arm, struts coupled between the wrist mount and the shoulder yaw joint and forming a 3D parallelogram that holds a face of the wrist mount in a vertical orientation perpendicular to an insertion direction, and a shoulder pitch motor coupled to actuate the shoulder pitch joint, the struts, the arm, and the wrist mount
Implementation Method 4
a yaw-pitch-roll wrist coupled to the face of the wrist mount, the yaw-pitch-roll wrist including a yaw joint actuated by one or more wrist yaw motors
Implementation Method 5
a differentially driven pitch-roll joint actuated by differentially driven pitch-roll motors
Implementation Method 6
an instrument mount coupled to the yaw-pitch-roll wrist, the instrument mount having one or more instrument motors providing an instrument drive
Data Source
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Figure 3~4A
AI summary
Embodiments of an instrument manipulator are disclosed. An instrument manipulator can include a track; a translational carriage coupled to ride along the track; a shoulder yaw joint coupled to the translational carriage; a shoulder pitch joint coupled to the shoulder yaw joint, the shoulder pith joint including an arm, a wrist mount coupled to the arm, struts coupled between the wrist mount and the shoulder yaw joint, and a shoulder pitch mechanism coupled to the arm; a yaw-pitch-roll wrist coupled to the wrist mount, the yaw-pitch-roll wrist including a yaw joint and a differentially driven pitch-roll joint; and an instrument mount coupled to the wrist. The various joints and carriages can be driven by motors.