Hybrid Flat Panel Detector with 2D Antiscatter Grid for Cone Beam CT

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Solution Overview

Problem

Current flat panel X-ray detectors face challenges in image quality due to scattered x-rays, which are not effectively suppressed by existing antiscatter grids, leading to deteriorated image quality and limitations in applications like adaptive radiation therapy.

Innovation Solution

A two-dimensional antiscatter grid design with tungsten septa, fabricated using Direct Metal Laser Sintering, is integrated directly with the flat panel detector, providing efficient scatter rejection and higher primary transmission, and a correction algorithm to address residual scatter intensity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a 2D antiscatter grid is used to stop scattered x-rays, then image quality is improved, but residual scatter transmission still deteriorates image quality

Engineering Contradiction:

Improveimage qualityVSAvoidresidual scatter transmission

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by increasing the grid ratio (height to width ratio) of the 2D antiscatter grid to enhance scatter rejection capability. By optimizing the grid ratio parameter, the system achieves better scatter suppression while managing primary transmission, directly addressing the contradiction between improving image quality and reducing residual scatter transmission.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If grid height is increased to reduce scatter transmission, then scatter rejection is improved, but other technical challenges arise that deteriorate image quality

Engineering Contradiction:

Improvescatter transmissionVSAvoidimage quality

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent optimizes the grid ratio parameter to balance scatter rejection and primary transmission. By carefully selecting and adjusting the grid height relative to the width, the system achieves effective scatter suppression without introducing excessive technical challenges that would degrade image quality, thus resolving the contradiction between reducing scatter transmission and maintaining image quality.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If a correction algorithm is applied to correct residual scatter intensity, then image quality is improved, but device complexity increases

Engineering Contradiction:

Improveimage qualityVSAvoidcorrection algorithm

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements a correction algorithm that processes detector signals to compensate for residual scatter intensity. This feedback mechanism analyzes the detected x-ray signals, identifies scatter components, and applies corrections to improve image quality. The algorithm acts as a computational feedback loop that continuously refines the image data to eliminate scatter-related artifacts.

Inventive Principle:

Principle #23Feedback

4Object-affected harmful factors

If a 2D grid design is implemented, then scatter rejection capability is enhanced, but manufacturing complexity increases

Engineering Contradiction:

Improvescatter rejectionVSAvoidgrid design fabrication

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent employs local quality by creating a 2D array of holes with specific geometric patterns and orientations. Each region of the grid is designed with tailored properties (hole size, shape, orientation) optimized for local scatter rejection requirements. This localized optimization approach enhances overall scatter rejection capability while allowing modular manufacturing processes that can simplify fabrication compared to uniform designs.

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 significantly enhances image quality by reducing scatter-to-primary ratios, improving CT number accuracy, and enabling better low contrast resolution, thus facilitating more accurate radiation therapy and improved CBCT image quality.

Implementation Method 1

The purpose of a 2D antiscatter grid is to stop scattered x-rays reaching a flat panel detector

Methodology Applied

Scientific EffectX-ray absorption: Absorption (EM radiation)

Implementation Method 2

Each pixel element comprises a scintillator overlying a photodetector

Methodology Applied

Scientific EffectScintillation: Scintillation

Implementation Method 3

Each pixel element comprises a scintillator overlying a photodetector, where the photodetector is configured to receive incident photons and generate an output signal

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS11723612B2Hybrid flat panel detector for cone beam CT systems

Publication Date: 2023.08.15 THE REGENTS OF THE UNIVERSITY OF COLORADO

AI summary

The present invention relates generally to X-ray detectors and more particularly to a system and a method for integrating an anti-scattering grid with scintillators to significantly enhance the performance of flat panel X-ray detector. In particular, the performance of a flat panel X-ray detector may be enhanced by photon counting detector pixels configured underneath the septa of a 2D antiscatter grid.