X-ray Collimation for Targeted 3D Image Reconstruction
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Solution Overview
Problem
Existing methods for reconstructing three-dimensional image data sets from two-dimensional projection images often result in high radiation exposure, as they require acquiring a large number of images across the entire acquisition region, even when only partial regions of interest need high-quality imaging, and existing zoom functions do not provide a significant gain in image information.
Innovation Solution
A method where first projection images are acquired without collimation to create a three-dimensional overview image data set, followed by second projection images taken from different angles with collimation focused on the partial region of interest, allowing for improved image quality in the selected region without excessive radiation, by acquiring new information that contributes to the reconstruction of the target image data set.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a large number of projection images are acquired across the entire acquisition region to ensure sufficient 3D image information, then the image quality across the entire acquisition region is improved, but the radiation exposure to the patient increases significantly
Solution Approach 1:
The patent applies local quality by differentiating image quality requirements across different regions of the acquisition volume. High-quality projection images are acquired only for the region of interest (ROI) while lower quality or no images are acquired for surrounding regions. This is implemented through collimation that restricts the x-ray beam to only illuminate the ROI during projection acquisition, thereby reducing radiation exposure to the entire patient volume while maintaining sufficient image quality for the clinically relevant region.
Solution Approach 2:
The patent segments the acquisition process into two distinct phases: a preliminary low-dose scan to identify the ROI, followed by a targeted high-quality acquisition phase focused only on the identified ROI. This segmentation allows the system to avoid acquiring unnecessary high-quality projection data from the entire acquisition region, thereby reducing overall radiation exposure while ensuring sufficient image quality for the region that actually requires detailed evaluation.
2Object-affected harmful factors
If collimation is applied to focus radiation only on the partial region of interest, then the radiation dose to the patient is reduced, but the field of view and coverage of the acquisition region are limited
Solution Approach 1:
The patent employs preliminary action by performing a low-dose preliminary scan of the entire acquisition region before the targeted ROI acquisition. This preliminary scan provides sufficient information to identify and localize the region of interest, enabling subsequent collimation to be accurately positioned. The preliminary action ensures that the field of view is temporarily expanded to cover the entire region, but only at low dose, allowing the high-dose collimated acquisition to be precisely targeted without missing the ROI.
3Manufacturing precision
If the entire acquisition region is scanned with high image quality, then all regions are suitable for detailed evaluation, but the acquisition time and data processing requirements increase
Solution Approach 1:
The patent applies local quality by matching image acquisition resources to actual clinical needs. Instead of uniformly acquiring high-quality projection images across the entire acquisition region, the system concentrates imaging resources only on the identified ROI. This results in high image quality for the clinically relevant region while reducing acquisition time and data processing requirements for the remaining volume, thereby improving overall acquisition efficiency without compromising diagnostic capability for the region that matters most.
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 method achieves high-resolution, high-contrast imaging with reduced noise and artifacts in the partial region of interest while maintaining lower image quality in less relevant areas, using a lower total radiation dose and avoiding redundant data acquisition, allowing for variable image quality across the acquisition region.
Implementation Method 1
first projection images are acquired without collimation of the x-ray source used from first projection directions
Implementation Method 2
second projection images are acquired with collimation at the partial region of interest from second projection directions
Implementation Method 3
a three-dimensional target image data set showing an examination object is determined from first and second projection images
Data Source
AI summary
In a method and x-ray device to determine a three-dimensional target image data set showing at least one partial region of interest of an acquisition region, wherein the image data of the three-dimensional target image data set are reconstructed from two-dimensional projection images acquired from various projection directions, first projection images are acquired without a collimation of the radiation source from first projection directions and a three-dimensional overview image data set of the acquisition region is reconstructed from the first projection images. The partial region of interest is selected in the overview image data set. Second projection images are acquired, with collimation at the partial region, from second projection directions, the second projection directions differing from the first projection directions. The target image data set showing the acquisition region and the partial region of interest is reconstructed from all first and second projection images.