Multi-leaf collimator leaf nut assembly for radiotherapy
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Solution Overview
Problem
Existing multi-leaf collimators face challenges in achieving accurate and efficient leaf positioning due to high-precision linear actuators, which are expensive and increase the device's volume and footprint, limiting integrability in radiotherapy devices.
Innovation Solution
A leaf assembly for a multi-leaf collimator is introduced, featuring a removably mounted leaf nut within the leaf profile, allowing for easier replacement and accurate positioning. The leaf nut is constrained to prevent rotational and longitudinal movement relative to the leaf, ensuring precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-precision linear actuators are used for leaf positioning, then positioning accuracy is improved, but device volume and footprint increase
Solution Approach 1:
The leaf drive unit is segmented into separate functional modules: a motor, a leaf nut, a leaf nut holder, and a leaf drive mount. This segmentation allows each component to be optimized independently and reduces the overall volume compared to a monolithic high-precision linear actuator while maintaining positioning accuracy through the threaded engagement mechanism.
Solution Approach 2:
The leaf nut is removably mounted within the profile of the leaf, and the leaf nut holder is integrated with the leaf drive mount. This nested arrangement allows compact integration of multiple components within the existing leaf structure, reducing the footprint without compromising positioning precision.
2Measurement precision
If high-precision linear actuators are used for leaf positioning, then positioning accuracy is improved, but manufacturing cost increases
Solution Approach 1:
By dividing the drive unit into separate modules (motor, leaf nut, leaf nut holder, mount), each component can be manufactured using standard precision machining processes rather than requiring expensive high-precision linear actuator assemblies. The threaded engagement provides sufficient precision at lower manufacturing cost.
Solution Approach 2:
The leaf nut is designed to be removable and replaceable, allowing for cost-effective maintenance and replacement rather than repairing expensive actuator components. This modular approach reduces overall system cost while maintaining positioning accuracy through the simple threaded mechanism.
3Measurement precision
If complex drive mechanisms are used for leaf positioning, then positioning accuracy is improved, but ease of repair deteriorates
Solution Approach 1:
The drive mechanism is segmented into modular components where the leaf nut can be independently removed and replaced without affecting other parts. This modularity significantly improves ease of repair while maintaining positioning accuracy, as damaged components can be quickly swapped rather than repaired.
Solution Approach 2:
The leaf nut is designed with removable mounting that allows dynamic access for maintenance. The nut can be easily detached and reattached, providing simple repair procedures while the threaded engagement ensures consistent positioning accuracy across multiple assemblies.
4Volume of moving object
If integrated leaf drive units are used, then device compactness is improved, but ease of maintenance deteriorates
Solution Approach 1:
The integrated drive unit is segmented into separable modules that maintain compactness when assembled but allow easy disassembly for maintenance. The leaf nut can be independently accessed and replaced while the overall assembly remains compact, resolving the contradiction between compactness and maintainability.
Solution Approach 2:
The mounting structure provides dynamic accessibility for maintenance while maintaining static compactness during operation. The removable leaf nut allows maintenance access without requiring disassembly of the entire drive unit, enabling easy maintenance while preserving device compactness.
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 solution enhances the accuracy and durability of leaf positioning, reduces maintenance complexity and costs, and allows for quicker access to individual leaves and leaf drive units, thereby minimizing radiotherapy device downtime.
Implementation Method 1
The leaf nut is constrained to prevent rotational and longitudinal movement relative to the leaf
Data Source
AI summary
A leaf assembly for a multi-leaf collimator comprises a leaf and a leaf nut removably mounted within the profile of the leaf, the leaf nut comprising a threaded hole for receiving a leaf actuator screw oriented along a first axis in the plane of the leaf. The leaf nut is mounted within the leaf such that relative movement between the leaf nut and the leaf is prevented both linearly along the first axis and rotationally about the first axis.