Collimator Modulation for X-ray Scatter Reduction
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Solution Overview
Problem
X-ray scatter in medical imaging systems, particularly in radiotherapy cone beam CT, leads to image quality deterioration and accuracy issues, affecting precise tumor treatment due to cup artifacts and reduced contrast.
Innovation Solution
A method involving a collimator module that moves to generate a modulated X-ray image group, with sub-zones combined to form a modulated image, and subsequent low-pass and high-pass filtering to calculate and subtract scatter components from X-ray images, improving image quality and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large area detector is used to receive X-rays in radiotherapy cone beam CT, then the detector can capture more X-ray signals for real-time imaging, but scattered rays account for a large proportion causing cup artifacts and image quality deterioration
Solution Approach 1:
The detector is divided into multiple sub-zones (first sub-zone, second sub-zone, third sub-zone) with different functions. The first sub-zone captures primary X-ray signals, while the second and third sub-zones are dedicated to measuring scatter signals from different directions. This segmentation allows simultaneous capture of both primary and scatter signals without interference, resolving the contradiction between signal capture and scatter artifacts.
Solution Approach 2:
A scatter correction component is introduced as an intermediary element that processes the scattered ray signals measured by the second and third sub-zones. This component calculates scatter correction values and applies them to the primary image data, effectively removing scatter artifacts while preserving the primary X-ray signal information.
2Object-affected harmful factors
If hardware tools such as anti-scatter grids are added to suppress scatter, then scatter artifacts are reduced, but the device complexity increases
Solution Approach 1:
The patent replaces mechanical scatter suppression devices (such as anti-scatter grids) with a computational scatter correction system. Instead of using physical hardware to block or filter scattered rays, the system uses software algorithms to measure, calculate, and subtract scatter signals from the detected X-ray data, thereby reducing device complexity while maintaining scatter correction effectiveness.
Solution Approach 2:
A scatter correction component serves as a software intermediary that processes raw detector signals to separate and remove scatter components. This computational approach eliminates the need for complex hardware interventions while achieving the same scatter reduction goal.
3Device complexity
If scatter correction is performed using software-based methods, then device complexity is reduced, but image accuracy may be compromised
Solution Approach 1:
Different sub-zones of the detector are assigned different measurement functions optimized for their specific roles. The first sub-zone is optimized for primary signal detection, while the second and third sub-zones are positioned and configured to specifically measure scatter signals from different angular directions. This local optimization ensures high measurement precision for each function while maintaining overall system simplicity.
Solution Approach 2:
The scatter correction system uses feedback from the scatter measurements taken by the second and third sub-zones to iteratively refine the scatter correction values. By continuously measuring scatter signals and adjusting correction parameters, the system achieves high image accuracy through adaptive scatter removal while maintaining hardware simplicity.
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
Enhances image quality by reducing scatter artifacts, improving signal-to-noise ratio, and enabling more precise radiotherapy by accurately reconstructing images with reduced scatter components.
Implementation Method 1
acquiring X-rays through a collimator module and an imaged object in sequence to generate an X-ray image group
Implementation Method 2
low-pass filtering the modulated X-ray image to obtain a combination of a low-frequency portion of the modulated X-ray image and scatter components of the modulated X-ray image
Implementation Method 3
high-pass filtering the modulated X-ray image to obtain a high-frequency portion of the modulated X-ray image
Implementation Method 4
acquiring X-rays through a collimator module and an imaged object in sequence to generate an X-ray image group
Data Source
AI summary
The present disclosure provides a system and method for X-ray imaging. The method of calculating scatter in an X-ray image may include forming a modulated X-ray image. The method of forming the modulated X-ray image may include acquiring X-rays through a collimator module and an imaged object in sequence to generate an X-ray image group; the acquisition may be performed during a movement of the collimator module in a first direction and the X-ray image group may include a plurality of X-ray images acquired at different times during the movement of the collimator; extracting sub-zones from the plurality of X-ray images in the X-ray image group; combining the sub-zones in the first direction to form the modulated X-ray image. In the present disclosure, an intensity distribution of the X-rays may be adjusted flexibly using a collimator without adding any extra hardware. In addition, scatter components in the X-ray images may be calculated to eliminate the scatter in the X-ray images finally.