Scattered Radiation Estimation in Cone-Beam CT Using Fan Blades
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cone-beam tomography systems face image degradation and artifacts due to scattered radiation, particularly in half-fan configurations, which affect the accuracy of CT images and reconstruction algorithms.
Innovation Solution
A method that estimates scattered radiation by obtaining two sets of radiographic projections, one with a wide band and another with a narrower band of pixels, allowing for the subtraction of scattered radiation from true image data, using fan blades to attenuate and block radiation and a controller to direct the mechanical drive for precise angular displacement and fan blade positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If cone-beam tomography is performed with wide radiation coverage, then imaging area is improved, but scattered radiation increases causing image degradation
Solution Approach 1:
The patent segments the radiation field by using multiple fan blades to create distinct narrow bands of radiation that pass through the object. Instead of using a single wide beam, the radiation is divided into multiple narrow bands, each contributing to the projection data. This segmentation reduces scattered radiation while maintaining comprehensive imaging coverage by combining data from multiple segments.
Solution Approach 2:
The patent extracts and removes scattered radiation components from the projection data through computational methods. By comparing projections taken with different fan blade configurations (different narrow bands), the system identifies and subtracts scattered radiation contributions, leaving only the primary radiation data needed for accurate image reconstruction.
2Measurement precision
If scattered radiation is reduced using narrow bands, then image quality is improved, but measurement time increases due to multiple scans
Solution Approach 1:
The patent performs preliminary measurements by acquiring projection data with different fan blade configurations (different narrow bands) before the actual image reconstruction. These preliminary measurements with narrow bands establish baseline data that is used to computationally remove scattered radiation from the full-width projection data, eliminating the need for multiple complete scans.
Solution Approach 2:
The patent uses partial action by acquiring projection data with only certain narrow bands activated at a time, rather than opening all fan blades simultaneously. This partial activation reduces scattered radiation in each measurement, and the incomplete data sets are later combined computationally to form the complete image, reducing total measurement time compared to multiple full scans.
3Object-affected harmful factors
If fan blades are used to create narrow bands, then scattered radiation is reduced, but device complexity increases
Solution Approach 1:
The patent introduces fan blades as intermediary components between the radiation source and the object. These fan blades act as mechanical mediators that selectively block or allow radiation to pass through, creating the narrow bands needed to reduce scattered radiation. The fan blades are positioned to rotate into and out of the radiation path, providing dynamic control over the radiation field without requiring complex modifications to the imaging system architecture.
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
This approach effectively reduces image artifacts and enhances the accuracy of CT images by isolating and subtracting scattered radiation, improving the quality of cross-sectional images and reducing numerical errors in reconstruction algorithms.
Implementation Method 1
with each fan blade being disposed closer to the source of radiation than the imaging device and adapted to significantly attenuate the radiation that strikes it
Implementation Method 2
collecting the non-absorbed radiation onto a two-dimensional imaging device, or imager, which comprises an array of pixel detectors (simply called 'pixels')
Implementation Method 3
The source's radiation generally propagates toward the imaging device in a volume of space defined by a right-circular cone having its vertex at the point source and its base at the imaging device
Implementation Method 4
when a quantum of radiation is absorbed by a portion of the object, one or more scattered rays are often generated that deviate from the transmission path of the incident radiation
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Disclosed are imaging systems, methods, and computer program products that generate estimates of scattered radiation in tomographic imaging systems, such as cone-beam computerized tomography (CBCT) systems, and the like. In an exemplary embodiment, a first group of projections is taken of an object with the radiation covering a wide band of the object, and a second group of projections is taken of the object with the radiation covering a narrower band of the object. The projections of the second group cover less of the object, but have less scattered radiation. The scattered radiation within the narrower band may be estimated from differences between projections from the first and second groups, or from representations thereof.