MRI Biopsy Depth Stop with Rotating Guide Cube
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Solution Overview
Problem
Current biopsy systems for MRI-guided procedures face challenges in accurately positioning and controlling the depth of needle insertion within the breast tissue, particularly in navigating the complex anatomy and maintaining secure engagement of depth stop devices with cannulas during biopsy procedures.
Innovation Solution
The proposed system incorporates a two-axis rotatable guide cube and a depth stop device with dual rotational capability, allowing for secure engagement and tactile feedback, along with a control module that segregates components from the MRI machine's magnetic field, enabling precise control and navigation of biopsy devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a depth stop device is used to control needle insertion depth, then positioning precision is improved, but device complexity increases due to secure engagement requirements
Solution Approach 1:
A rotatable cube guide is introduced as an intermediary component between the depth stop device and the cannula. The rotatable cube guide features a recess that receives the depth stop device and a protrusion that engages with the cannula, simplifying the engagement mechanism while maintaining precise depth control through the mediating structure
Solution Approach 2:
The depth stop device is made rotatable relative to the rotatable cube guide, allowing dynamic adjustment of the depth stop position. This rotational capability enables the operator to securely engage the depth stop device at different depths while maintaining a simple engagement mechanism through the rotating interaction
2Ease of operation
If a rotatable guide cube is used for positioning, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The rotatable cube guide serves multiple functions simultaneously: it acts as a positioning guide for the needle, a depth stop mechanism, and a rotational adjustment device. By integrating these functions into a single component, the overall device complexity is reduced despite the added rotational capability
Solution Approach 2:
The depth stop device is nested within the rotatable cube guide structure, with the depth stop device fitting into a recess of the rotatable cube guide. This nested arrangement allows compact integration of multiple functional elements, reducing overall device complexity while maintaining ease of operation
3Reliability
If control module is segregated from MRI machine, then reliability is improved by protecting from magnetic field, but device complexity increases due to separate control system
Solution Approach 1:
The control module is segmented and physically separated from the MRI machine, with the biopsy device serving as an independent control unit. This segmentation protects the control electronics from the MRI magnetic field while maintaining functional independence, improving reliability through isolation
Data Source
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AI summary
A bi-directional depth stop for use with biopsy instrument including a body and a pair of blades. The body defines a channel sized to receive a cannula associated with the biopsy instrument. The channel includes a first pair of opposing concave surfaces and a second pair of opposing concave surfaces. The first pair and second pair of opposing concave surfaces together form a superimposed bi-oval-shaped cross-section. Each blade of the pair of blades projects inwardly into a concave surface of the first pair of opposing concave surfaces such the pair of blades are disposed on an opposing side of the body. In some instances, the concave surfaces may be beneficial to provide rotation of the dept stop in two directions rather than a single direction.