Segmented Radiotherapy Collimator Weight Reduction
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Solution Overview
Problem
Conventional block collimators in radiotherapy apparatuses are heavy due to the use of solid tungsten, leading to increased weight and structural deformation issues, which complicates the control systems and radiation beam attenuation.
Innovation Solution
A collimator design with a block of radiation-attenuating material featuring a front face and non-parallel main rear faces, such as a concave V-shape, reduces the size and weight by optimizing the shape to match the trajectory of multi-leaf collimator leaves, allowing for reduced material usage and weight savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional block collimator uses solid tungsten material to provide effective radiation attenuation, then the radiation shielding performance is improved, but the weight of the collimator increases significantly
Solution Approach 1:
The collimator block is segmented into multiple sections along its length, with varying thicknesses. The front section has greater thickness for maximum attenuation, while rear sections have reduced thickness where less attenuation is needed, optimizing the balance between radiation shielding and weight reduction.
Solution Approach 2:
Different sections of the collimator block are designed with different thicknesses according to the local radiation attenuation requirements. The thickness profile is optimized so that each section provides adequate shielding for its specific position, reducing overall material usage and weight while maintaining effective radiation protection.
2Reliability
If the collimator block thickness is increased to reduce radiation leakage, then the radiation shielding performance is improved, but the weight and structural deformation increase
Solution Approach 1:
The collimator is divided into segments with optimized thickness distribution. The front segment provides maximum attenuation where radiation leakage is most critical, while subsequent segments have progressively reduced thickness, minimizing total material mass and structural deformation while maintaining adequate shielding performance.
Solution Approach 2:
The thickness parameter of the collimator block is varied along its length rather than being uniform. This parameter change optimizes the balance between radiation attenuation effectiveness and structural stability, providing sufficient shielding where needed while reducing overall weight and deformation.
3Reliability
If a pair of block collimators is used to cover the entire aperture width, then the radiation shielding performance is improved, but the device complexity and weight increase
Solution Approach 1:
The collimator system is segmented into functional sections with different thickness profiles. This segmentation allows for optimized radiation shielding in critical areas while reducing material usage and system complexity in areas where full attenuation is less critical, thereby simplifying the overall device configuration.
Solution Approach 2:
Different regions of the collimator are designed with locally optimized thicknesses based on the radiation leakage risk at each position. This local quality approach ensures adequate shielding where needed while reducing complexity and weight in regions with lower shielding requirements.
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 design effectively reduces the weight of the collimator while maintaining radiation shielding, minimizing radiation leakage and structural deformation, thus enhancing the efficiency and precision of radiotherapy apparatuses.
Implementation Method 1
a block of radiation-attenuating material for moving into and out of a beam of therapeutic radiation
Data Source
AI summary
A collimator for a radiotherapy apparatus, comprising a block of isolation-attenuating material having a front face forming the leading edge of tie block and at least one main rear face defining the trailing edge of the block, in which the or each rear face is substantially planar in the direction of the depth of the block and non-parallel to the front face. The collimator may form part of a radiotherapy apparatus, and methods of operation of such apparatus are described.