Multi-leaf collimator leaf assembly lateral movement
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Solution Overview
Problem
Multi-leaf collimators in radiotherapy suffer from leakage radiation due to gaps between adjacent leaves, which are unavoidable in current designs, leading to inexact and potentially harmful irradiation treatments.
Innovation Solution
The leaf assembly allows lateral movement of leaves to superpose linear guidance, enabling mutual abutting of adjacent leaves and eliminating gaps, thereby preventing leakage radiation. This is achieved through conical leaf designs, inclined upward movement, grooves in the leaf frame, laterally flexible elements, and tiltable leaf sides, ensuring complete shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a small gap remains between adjacent leaves to enable individual displacement, then leaf adjustability is improved, but leakage radiation increases
Solution Approach 1:
The patent introduces lateral movement capability to leaves, adding a second dimension of motion (lateral direction) to the primary adjusting direction. This enables leaves to move sideways and abut against each other, closing gaps that would otherwise allow leakage radiation, while preserving the ability to individually position leaves along the adjusting direction.
Solution Approach 2:
The leaf frame is designed to allow dynamic lateral movement of leaves superposing the linear guidance. This dynamic capability enables leaves to adapt their positions laterally to achieve mutual abutting and eliminate gaps, while maintaining the primary adjusting function along the linear guidance path.
2Object-generated harmful factors
If lateral movement is allowed to enable mutual abutting, then leakage radiation is reduced, but device complexity increases
Solution Approach 1:
The patent combines the linear guidance function with lateral movement capability into a unified leaf frame structure. The grooves in the leaf frame simultaneously provide linear guidance along the adjusting direction and constrain lateral movement to achieve mutual abutting, merging multiple functions into a single integrated mechanism rather than adding separate complex systems.
Solution Approach 2:
The leaf frame structure serves multiple functions: it provides linear guidance for individual leaf adjustment, enables lateral movement for mutual abutting, and maintains the mechanical linkage for radiation field shaping. This multi-functionality reduces the need for additional separate mechanisms and lowers overall device complexity.
Data Source
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AI summary
The invention relates to a leaf assembly (102) for a multi-leaf collimator, comprising a leaf frame (104) and a plurality of leaves (106) for shielding beams (108) from a selected area, wherein the leaves (106) are arranged sideways and adjacently in the leaf frame (104) for shielding beams (108) being emitted from a radiation source (110) located above the assembly (102), wherein each leaf (106) is mounted in the leaf frame (104) displaceably in an adjusting direction (112) being oriented perpendicularly related to said beams (108), and wherein the leaf frame (104) provides a linear guidance (114) for each leaf (106) within the adjusting direction (112), being designed in a such a way that the leaf frame (104) is adapted to allow for lateral movement of the leaves (106) superposing said linear guidance (114), thus allowing mutual abutting of the leaves (106). Furthermore, the invention relates to a multi-leaf collimator comprising two leaf assemblies (102) according to the invention, wherein the assemblies (102) are arranged to face each other within the adjusting direction (112). The invention is based on the objective of designing a leaf assembly (102) for a multi-leaf collimator and a multi-leaf collimator in such a way that the occurrence of leak-age radiation may be diminished.