Multi-leaf collimator with compact gear segment drive
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Solution Overview
Problem
Current multi-leaf collimators for high-energy radiation therapy require a large number of electric motors and drive transmissions, making them bulky and heavy, which complicates their integration within the irradiation head and limits their mobility and precision in shaping irregularly formed treatment objects like tumors.
Innovation Solution
The design incorporates a compact and lightweight leaf drive system with gear rod-like engagement, where segment disks and pinions are arranged in an arch-like pattern on a bearing block, allowing for staggered motor-side gear segments and adjustable mounting to reduce space and weight, enabling precise control of high-energy beams without increasing the collimator's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If each leaf is assigned an electric motor and drive transmission, then positioning precision is improved, but device weight and volume increase
Solution Approach 1:
Multiple individual motor drives are merged into a single centralized drive unit that controls all leaves through a common rack gear mechanism. The segment disk with gear segments replaces multiple individual pinions, consolidating the driving function into one location while maintaining individual leaf positioning capability through selective engagement of different gear segments.
Solution Approach 2:
The centralized drive unit performs multiple functions: it positions all leaves individually, maintains precise positioning through the rack-gear mechanism, and enables coordinated movement of multiple leaves simultaneously. The single drive unit serves as both the actuator and the positioning control system for the entire collimator assembly.
2Manufacturing precision
If each leaf is assigned an electric motor and drive transmission, then positioning precision is improved, but device complexity increases
Solution Approach 1:
Multiple individual motor drives are merged into a single centralized drive unit that controls all leaves through a common rack gear mechanism. The segment disk with gear segments replaces multiple individual pinions, consolidating the driving function into one location while maintaining individual leaf positioning capability through selective engagement of different gear segments.
Solution Approach 2:
The drive system is segmented into modular components: a centralized motor unit, a segment disk with multiple gear segments, a common rack gear, and individual leaf assemblies. This segmentation allows for easier manufacturing, assembly, and maintenance while reducing overall system complexity compared to fully distributed individual motors.
3Manufacturing precision
If more and thinner leaves are used to re-create treatment object shape, then treatment precision is improved, but drive system volume increases
Solution Approach 1:
Multiple individual motor drives are merged into a single centralized drive unit that controls all leaves through a common rack gear mechanism. The segment disk with gear segments replaces multiple individual pinions, consolidating the driving function into one location while maintaining individual leaf positioning capability through selective engagement of different gear segments.
Solution Approach 2:
The drive system transitions from a distributed three-dimensional arrangement of individual motors to a centralized two-dimensional segment disk layout. The gear segments are arranged radially on the segment disk, allowing multiple leaves to be controlled from a single plane, thereby reducing the overall volume required for the drive system.
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
This configuration allows for a more compact and lightweight collimator that can accurately shape high-energy beams, enhancing mobility and reducing treatment time by enabling faster repositioning of the irradiation head, thus improving the efficiency and cost-effectiveness of radiation therapy.
Implementation Method 1
a pinion drivable by a motor engaging with the motor-side gear segment
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The invention relates to a multi-leaf collimator (1) with leaf drives (2), with two sets (4, 4') of displaceable leaves (3, 3', 3",...) arranged side by side of each other and facing each other in order to impress a high-energy beam (5) with the shape of an irregularly formed treatment object (6) by enabling each of the leaves (2) to assume a position oriented along the shape of the treatment object (6) by means of a leaf drive (2), with the leaf drives (2) being designed in such a way that the leaves (3, 3', 3",...) are each equipped with a gear rod-like drive engagement (8, 8', 8",....) in the direction of the displacement (7). The invention facilitates a design of leaf drives as compact and lightweight as possible and an advantageous arrangement in an irradiation head due to the fact that a leaf-side pivotable gear segment (9, 9', 9",... ) located, together with a motor-side gear segment (10, 10', 10",...), on a segment disk (11, 11', 11",...) engages with the gear rod-like drive engagement (8, 8', 8",....), with a pinion (13) drivable by a motor (12) engaging with the motor-side gear segment (10, 10', 10',...); that the segment discs (11, 11', 11",...) are arranged side by side for each set (4, 4') of leaves (3, 3', 3",...) as a package (15) on one axis (14); and that the motor-side gear segments (10, 10', 10",...) of two segment disks (11, 11', 11",...) located next to each other are staggered in such a way that they will not abut each other; that the segment disks (11, 11', 11",...) are positioned on a radiation source-facing side (46) of the leaves (3, 3', 3",...); and that the segment disks (11, 11', 11",...) have a radius (R) that is comparable to a predefined range of displacement (D) of the leaves (3, 3', 3",...).