Electromagnetically Actuated Multi-Leaf Collimator for Rapid Beam Shaping

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Solution Overview

Problem

Conventional multileaf collimators in radiation therapy are limited by slow leaf movement and insufficient control, which restricts the ability to achieve advanced simultaneous shaping and modulating beam patterns, hindering the development of sophisticated treatment plans.

Innovation Solution

A highly responsive multileaf collimator with magnetically actuated leaves that can move quickly between fully open and fully closed positions, allowing for precise control and arbitrary 2D patterns, combining the speed benefits of binary MLCs with the flexibility of conventional shaping MLCs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional mechanical actuation is used for multileaf collimator leaves, then structural simplicity is maintained, but leaf movement speed is slow and control precision is insufficient

Engineering Contradiction:
Improveleaf movement speedVSAvoidactuation system complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical actuation systems with electromagnetic actuators (motors) to drive the multileaf collimator leaves. This substitution enables significantly faster leaf movement speeds while providing precise control through electrical signal regulation, directly resolving the contradiction between speed and control precision without excessive mechanical complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs variable speed control of the electromagnetic actuators, allowing the leaves to move at different speeds depending on position and treatment requirements. The system can accelerate rapidly when needed and decelerate precisely at target positions, optimizing both overall speed and positioning accuracy while maintaining manageable system complexity through electronic parameter regulation

Inventive Principle:
Principle #35Parameter changes

2Productivity

If conventional shaping MLC is used, then flexibility in beam shaping is achieved, but treatment time increases due to slow leaf movement

Engineering Contradiction:
Improvetreatment delivery speedVSAvoidbeam shaping flexibility
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent implements dynamic leaf movement where the leaves can change position and velocity continuously during treatment delivery. The electromagnetic actuators allow for arbitrary motion trajectories, enabling the system to rapidly transition between different beam shapes and maintain optimal shaping flexibility while dramatically reducing overall treatment time compared to conventional slow mechanical systems

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system pre-calculates and pre-positions leaves for subsequent beam shapes during the delivery of current shapes. The high-speed electromagnetic actuators enable leaves to move to predetermined positions in advance, allowing for overlapping preparation and execution of multiple beam shaping operations, thereby increasing productivity without sacrificing shaping precision or flexibility

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If binary MLC is used, then leaf movement speed is improved, but ability to create arbitrary 2D patterns and intensity modulation is reduced

Engineering Contradiction:
Improvebeam pattern versatilityVSAvoidleaf positioning speed
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent creates a universal leaf actuation system that can perform both binary (fully open/closed) positioning and continuous multi-position positioning within the same system. The electromagnetic actuators provide multi-functional capability, enabling the leaves to operate in binary mode for high-speed applications or in continuous mode for complex 2D pattern creation and intensity modulation, thus achieving both speed and versatility through a single unified system

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables more advanced radiation therapy treatments by allowing for rapid creation of complex beam shapes and intensity modulation, improving treatment planning and delivery efficiency.

Implementation Method 1

A highly responsive multileaf collimator with magnetically actuated leaves that can move quickly between fully open and fully closed positions

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnetic Propulsion

Data Source

PatentEP2962309B1Electromagnetically actuated multi-leaf collimator
Publication Date: 2022.02.16 ACCURAY INC
  • EP2962309B1 patent drawingFigure 1
  • EP2962309B1 patent drawingFigure 2
  • EP2962309B1 patent drawingFigure 3

AI summary

A multi-leaf collimator with electromagnetically actuated leaves. The multi-leaf collimator includes a plurality of leaves, a leaf guide configured to support the plurality of leaves, and a plurality of magnets. Each leaf includes a blocking portion that is radio opaque, a drive portion connected to the blocking portion, and a coil embedded in the drive portion. The coil is operatively connected to an electrical current source to generate a first magnetic field. The first magnetic field interacts with the magnetic field generated by the magnet to thereby move the leave to a desired state. The leaves have the capability of moving at speeds of 50 cm/s up to and higher than 1 m/s.