Radiolucent Head Clamp with Relocated Adjustment Mechanisms
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Solution Overview
Problem
Current head clamps for combined MR and X-ray imaging systems fail to meet the radiolucency requirements, as they interfere with X-ray imaging due to material volume and placement of adjustment mechanisms, causing unacceptable artifacts and not being FDA compliant with attenuation factors.
Innovation Solution
A head fixation device with a C-shaped support and dual adjustment systems, where the coarse and fine adjustments are consolidated and located out of the primary imaging fields, using PEEK material to minimize attenuation and radiopacity, with a mechanism that applies and measures pinning force at the base of the skull clamp, keeping it out of the imaging field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If adjustment mechanisms are placed on the skull clamp for ease of operation, then the clamp can be adjusted to fit different patients, but the adjustment mechanisms interfere with X-ray imaging and cause artifacts
Solution Approach 1:
The adjustment mechanisms are extracted from the skull clamp structure and relocated to the base of the C-shaped support. This separation removes the harmful adjustment components from the imaging field while preserving their functionality for operating the clamp
Solution Approach 2:
The adjustment mechanisms are positioned in a different spatial dimension (at the base rather than on the clamp arms) so that they lie outside the primary imaging planes. This dimensional relocation allows the clamp to remain radiolucent in the imaging field while maintaining full adjustment capability
2Strength
If material volume is increased to provide structural support and adjustment mechanisms, then the clamp can support the skull and provide adjustment functionality, but the material volume causes unacceptable attenuation and reduces radiolucency
Solution Approach 1:
The C-shaped support is designed with non-uniform material distribution - the legs and base have sufficient material for structural strength, while the portions within the imaging field are minimized. The adjustment mechanisms are placed in the base where they do not interfere with imaging, allowing local optimization of material placement
Solution Approach 2:
The skull clamp is constructed from composite materials that provide high strength-to-density ratio. The C-shaped support uses materials that are both mechanically strong for supporting the skull and radiolucent for clear X-ray imaging, achieving both structural requirements and imaging compatibility
3Object-generated harmful factors
If the clamp structure is simplified to reduce material volume, then radiolucency is improved, but the structural integrity and adjustment capability may be compromised
Solution Approach 1:
The skull clamp system is segmented into distinct functional components: the C-shaped support for positioning, the clamp arms for engagement, and the base for housing adjustment mechanisms. This segmentation allows each component to be optimized for its specific function while minimizing overall material volume and radiopacity
Data Source
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AI summary
A head clamp for Magnetic Resonance and X-ray imaging is generally C-shaped including a base and two legs carrying pin clamp members. A course and fine adjustment system allows one of the clamp members to move inwardly relative to the other and then to be finely adjusted so as to apply a clamping force to the skull. The C-shaped support member comprises a truss with a C-shaped inner band adjacent the skull, an outer band generally following the shape of inner band and a plurality of openings defining spaced bars between the inner band and the outer band. The adjustment system comprises a screw that adjusts the width of the C-shaped member at the base and at one leg and includes a gauge to measure force applied with the mechanism located outside the field of view of the head both vertically and horizontally.