X-ray Collimation for Displaced Focal Spots
Solution Overview
Problem
Current X-ray collimation systems are limited in their ability to effectively utilize X-ray radiation when focal spots are spaced apart, leading to reduced field of view and inefficient radiation use in medical imaging.
Innovation Solution
An X-ray source arrangement with a shutter device featuring pairs of shutters with outer solid structures and inner grid structures that allow for optimized collimation and minimal radiation attenuation, enabling the use of X-ray radiation from multiple focal spots by aligning X-ray passages to focus on specific focal spot positions, allowing for geometric selective transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fixed shutters are used for collimation with two displaced focal spots, then the beam is properly collimated for each focal spot, but the field of view is limited due to cutting off parts of the respective other image
Solution Approach 1:
The shutter device is divided into multiple independent shutter pairs, each pair responsible for collimating X-rays from a specific focal spot. This segmentation allows each shutter pair to be optimized for its designated focal spot while not interfering with the field of view for other focal spots, thereby resolving the contradiction between collimation precision and field of view.
2Measurement precision
If wedge-shaped attenuation filters are used to improve image quality, then image quality is improved, but the system complexity increases due to additional components
Solution Approach 1:
The shutter elements are designed to perform multiple functions: they provide collimation for their designated focal spot, act as attenuation filters for X-rays from other focal spots, and define the beam geometry. This multi-functionality eliminates the need for separate wedge-shaped attenuation filters, thereby improving image quality while avoiding increased system complexity.
3Manufacturing precision
If outer shutter elements are positioned to limit the diaphragm, then beam boundaries are properly defined, but X-ray radiation from other focal spots is unnecessarily attenuated
Solution Approach 1:
Each shutter pair is positioned and configured with specific local properties optimized for its designated focal spot. The shutter elements have varying attenuation characteristics and geometric configurations that are locally optimized to define beam boundaries for one focal spot while being transparent or minimally attenuating to X-rays from other focal spots, thereby resolving the contradiction between beam boundary definition and X-ray energy loss.
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 solution ensures optimized collimation and efficient use of X-ray radiation from multiple focal spots, enhancing image quality and radiation utilization while minimizing attenuation, thus addressing the limitations of existing systems.
Implementation Method 1
The grid structure of the first inner shutter element comprises a plurality of first X-ray passages that are focused on the second focal spot position; and the grid structure of the second inner shutter element comprises a plurality of second X-ray passages that are focused on the first focal spot position
Implementation Method 2
The boundary portions of the X-ray passages, i.e. the so-to-speak sidewalls of the passages, provided by the grid structure are acting as absorbing structure, or X-ray non-transparent structure
Implementation Method 3
The outer shutter elements comprise a solid/opaque structure in X-ray radiation direction
Data Source
AI summary
The present invention relates to collimation of X-ray radiation and comprises an X-ray source arrangement for medical imaging, the X-ray source arrangement comprising an X-ray source, and an X-ray beam shutter device. The X-ray source has at least at a first and a second focal spot position distanced apart from each other in a direction transverse to a main radiation direction. The X-ray beam shutter device comprises at least a first pair of shutters defining a first diaphragm, and at least a second pair of shutters defining a second diaphragm. The first pair of shutters is configured for alignment with a first line-of-sight between the first focal spot position and a center of a detector, and the second pair of shutters is configured for alignment with a second line-of-sight between the second focal spot position and a center of a detector. The first and the second diaphragm partly overlap.