Source Dispensing Unit for Precise Needle Retraction
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Solution Overview
Problem
Existing endoscopic procedures for implanting sources such as radioactive seeds face challenges in achieving precise positioning, requiring high expertise and often result in suboptimal placement leading to decreased effectiveness or tissue damage.
Innovation Solution
A source dispensing unit (SDU) is attached to a needle assemblage, enabling semi-automatic control over a hollow needle, sheath, and stylet, allowing independent manipulation and precise positioning of sources within the patient by translating the stylet relative to the needle during retraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual implantation of sources is performed by experts, then positioning precision can be achieved, but the procedure requires high expertise and is difficult to perform
Solution Approach 1:
A source dispensing unit is introduced as an intermediary device between the operator and the sources. This unit includes a needle assemblage with a hollow needle, stylet, and retaining bar that mechanically controls source movement and deployment, allowing non-experts to achieve precise positioning through simple operational controls
Solution Approach 2:
The needle assemblage is designed to automatically maintain source positioning through its mechanical structure. The stylet and retaining bar work together to self-maintain source location during needle retraction, eliminating the need for continuous expert intervention and manual adjustment
2Ease of operation
If sources are implanted with small deviations from target position, then the procedure may be easier to perform, but effectiveness decreases and healthy tissue may be damaged
Solution Approach 1:
The needle assemblage provides mechanical feedback through the stylet-stylet engagement with sources and the retaining bar structure. This feedback mechanism ensures sources remain properly positioned during deployment, preventing deviations from target location and ensuring procedure effectiveness
Solution Approach 2:
The hollow needle acts as an intermediary that precisely guides sources to the target location. The needle's structural integrity and alignment mechanisms ensure sources are delivered exactly to the intended position, preventing deviations that could reduce effectiveness or damage healthy tissue
3Device complexity
If a simple needle structure is used for source implantation, then the device complexity is reduced, but positioning precision and control are compromised
Solution Approach 1:
The implantation system is segmented into distinct functional components: the hollow needle for delivery, the stylet for source engagement and positioning, the retaining bar for source retention, and the source dispensing unit for control. This segmentation allows each component to be optimized for its specific function while maintaining overall positioning precision without excessive complexity
Solution Approach 2:
The needle assemblage employs a nested structure where the stylet is inserted within the hollow needle, and sources are contained within the needle lumen. The retaining bar is positioned within the needle structure. This nesting allows multiple functional elements to be integrated in a compact manner, achieving precise control without proportionally increasing device complexity
Data Source
AI summary
Apparatus for control of a needle assemblage having a handle coupled to a hollow needle and a stylet penetrating the hollow needle. The apparatus includes a retaining bar and a connector slidingly mounted on the retaining bar that is configured to fixedly attach to the handle. The connector has a control which in a first position causes translation of the connector proximally on the retaining bar by a preset distance to translate the handle and the hollow needle proximally by the preset distance and to translate the stylet distally by the preset distance with respect to the connector. In a second position the control causes translation of the connector on the retaining bar by the preset distance to translate the handle, the hollow needle, and the stylet by the preset distance.