Dual-Density Proton Therapy Collimator Leaf

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Solution Overview

Problem

Conventional multi-leaf collimators for proton therapy are heavy and costly due to thick leaves required to block proton beams, making them difficult to manipulate and increasing inertia, which restricts their use on gantries and increases treatment complexity.

Innovation Solution

Designing multi-leaf collimators with leaves of reduced size and weight, featuring two regions of different densities, where a high-density region is used for blocking the proton beam and a lower-density region provides structural support, allowing for precise beam shaping and reduced overall weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thick leaves are used to block proton beams, then beam blocking capability is improved, but weight and cost increase

Engineering Contradiction:

Improvebeam blocking capabilityVSAvoidcollimator weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The leaf is divided into two distinct regions: a first region with high density material (such as tungsten or lead) positioned to intercept and block the proton beam, and a second region with lower density material providing structural support. This local differentiation allows the leaf to achieve effective beam blocking only where needed while reducing overall weight compared to uniformly thick leaves.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The leaf combines different materials with different density characteristics - a high-density material for the beam-blocking first region and a lower-density material for the structural second region. This composite structure optimizes both beam blocking performance and weight reduction, resolving the contradiction between reliability and weight.

Inventive Principle:

Principle #40Composite materials

2Reliability

If thick leaves are used to block proton beams, then beam blocking capability is improved, but manipulation difficulty increases

Engineering Contradiction:

Improvebeam blocking capabilityVSAvoidmanipulation ease

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

By concentrating the high-density blocking material only in the first region where beam interception is needed, rather than distributing it uniformly throughout the entire leaf, the overall weight is reduced. This makes the leaves easier to manipulate and reposition during treatment while maintaining effective beam blocking capability.

Inventive Principle:

Principle #3Local quality

3Reliability

If thick leaves are used to block proton beams, then beam blocking capability is improved, but inertia increases

Engineering Contradiction:

Improvebeam blocking capabilityVSAvoidinertia

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The composite leaf structure uses high-density material only for the functional beam-blocking region while using lower-density material for structural support. This reduces the overall mass and moment of inertia of the leaf assembly, enabling faster acceleration and deceleration during dynamic treatment protocols while maintaining reliable beam blocking.

Inventive Principle:

Principle #40Composite materials

4Weight of moving object

If reduced size leaves are used, then weight is reduced, but beam blocking capability may be compromised

Engineering Contradiction:

Improvecollimator weightVSAvoidbeam blocking capability

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The leaf employs local quality differentiation by placing high-density blocking material specifically in the first region that interfaces with the proton beam. This targeted approach ensures effective beam blocking is maintained despite the overall reduced size and weight of the leaf, as the critical blocking function is concentrated where it matters most.

Inventive Principle:

Principle #3Local quality

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 enables more precise radiation delivery to tumors while sparing surrounding tissues, reducing the weight and cost of the collimator, making it easier to maneuver and integrate into proton therapy systems, thereby improving treatment precision and efficiency.

Implementation Method 1

The first region is operable for blocking a portion of an incident beam of radiation passing proximal to the first region

Methodology Applied

Scientific EffectRadiation attenuation: Absorption (EM radiation)

Implementation Method 2

the second region providing structural support for the first leaf

Methodology Applied

Scientific EffectStructural support:

Data Source

PatentUS9795805B2Proton therapy multi-leaf collimator beam shaping

Publication Date: 2017.10.24 SIEMENS HEALTHINEERS INTERNATIONAL AG

AI summary

System and method for shaping the intensity profile of a radiation beam incident on a target volume. Embodiments according to the present disclosure include a multi-leaf collimator (MLC) capable of sharpening (e.g., “trimming”) a proton beam, the MLC having a reduced overall weight. Leaves of the MLC according to embodiments of the present disclosure have two regions of different density, where a high density region is proximal to a radiation beam so as to block a portion of the beam, and a lower density region provides structural integrity to the leaf while reducing overall MLC weight.