Composite X-ray Collimator for CT Systems

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Solution Overview

Problem

In computed tomography (CT) imaging systems, pre-patient collimators made from high-density materials like tungsten and lead face challenges with increased centripetal acceleration and weight issues in newer systems, affecting dynamic balance and are non-compliant with environmental regulations.

Innovation Solution

A composite material pre-patient x-ray collimator is designed with a lower density structural base and a high-density radiation blocking insert, mechanically coupled without adhesives or fasteners, using materials like aluminum for the base and tungsten impregnated plastic for the insert, optimized for radiation blocking and structural support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pre-patient collimator is constructed from high-density materials like tungsten or lead, then radiation blocking ability is improved, but weight increases and dynamic balance deteriorates

Engineering Contradiction:

Improveradiation blocking abilityVSAvoidcollimator weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The collimator uses a composite structure combining a low-density aluminum base with a high-density tungsten insert. The aluminum base provides structural support while the tungsten insert provides radiation blocking. This composite approach achieves the required radiation attenuation without the full weight penalty of a monolithic tungsten collimator, improving dynamic balance and reducing G-load effects in newer CT systems with larger bore sizes and faster rotation speeds.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The collimator is divided into two functional segments: a structural base and a radiation blocking insert. This segmentation allows each component to be optimized for its specific function - the aluminum base for mechanical support and the tungsten insert for radiation attenuation - thereby reducing overall weight while maintaining radiation blocking performance.

Inventive Principle:

Principle #1Segmentation

2Reliability

If a pre-patient collimator is constructed from monolithic tungsten, then radiation blocking ability is improved, but manufacturing difficulty and cost increase

Engineering Contradiction:

Improveradiation blocking abilityVSAvoidmanufacturing ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of machining a monolithic tungsten collimator, the invention uses a composite construction with an aluminum base and a tungsten insert. The aluminum base is easier and less expensive to machine, and the tungsten insert can be manufactured separately and attached, significantly reducing manufacturing complexity and cost while maintaining radiation blocking performance.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The collimator is segmented into a base component and an insert component that can be manufactured independently using different processes optimized for each material, then assembled together. This avoids the need to machine the entire collimator from difficult-to-work tungsten, reducing manufacturing difficulty and cost.

Inventive Principle:

Principle #1Segmentation

3Reliability

If lead is used as a pre-patient collimator material, then radiation blocking ability is improved, but environmental compliance deteriorates

Engineering Contradiction:

Improveradiation blocking abilityVSAvoidenvironmental compliance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the material parameter from lead to tungsten for the radiation blocking insert. Tungsten has similar or superior radiation blocking properties to lead but does not pose the same environmental and health hazards, ensuring compliance with the Restriction of Hazardous Substances Directive (RoHS) while maintaining radiation attenuation performance.

Inventive Principle:

Principle #35Parameter changes

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 composite collimator reduces weight and cost while maintaining radiation blocking ability and environmental compliance, improving the dynamic balance and agility of the CT system, and allowing for easier machining and reduced waste.

Implementation Method 1

the second material comprising a moldable material having a second material density greater than the first material density and that is sufficient to block high frequency electromagnetic energy

Methodology Applied

Scientific EffectRadiation blocking: Absorption (EM radiation)

Data Source

PatentUS8699668B2Composite material x-ray collimator and method of manufacturing thereof

Publication Date: 2014.04.15 GE PRECISION HEALTHCARE LLC

AI summary

A composite material pre-patient collimator for shaping an x-ray beam in a computed tomography (CT) system is disclosed. The pre-patient collimator includes a base comprised of a first material having a first material density and an insert mechanically coupled to the base and being comprised of a second material, the second material comprising a moldable material having a second material density greater than the first material density and that is sufficient to block high frequency electromagnetic energy. The base comprises a plurality of structural features by which the insert is molded to the base, with the moldable material of the insert forming a connection with the plurality of structural features to mechanically couple the base and the insert.