X-ray Tube and Detector Parallel Motion for Long FOV Imaging
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Solution Overview
Problem
X-ray body section imaging apparatuses have a limited field of view, especially when using flat panel detectors, due to the parallel movement of the X-ray tube and detector, which results in decreased resolution as the projection angle deviates from the vertical, limiting the ability to obtain long field-of-view sectional images in the longitudinal direction.
Innovation Solution
A radiographic apparatus design where the X-ray tube and detector move parallel to each other in the same direction along the patient's longitudinal axis, with intermittent radiation emission and detection, followed by image decomposition and composition for each projection angle, allowing for reconstruction of sectional images with a longer field of view through a reconstruction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the X-ray tube and detector move parallel to each other in opposite directions, then the projection angle can be varied to obtain sectional images, but the resolution decreases as the projection angle deviates from the vertical
Solution Approach 1:
The patent inverts the conventional approach by moving the X-ray tube and detector parallel to each other in the same direction rather than opposite directions. This maintains a substantially constant projection angle throughout the scanning process, preventing the resolution degradation that occurs when the projection angle deviates from vertical in conventional systems.
2Measurement precision
If the X-ray tube and detector move parallel to each other in the same direction, then the projection angle can be maintained at substantially the same angle, but only projection images can be obtained without sectional images
Solution Approach 1:
The patent applies segmentation by dividing the acquired projection images into multiple sets based on different projection angles. Even though the tube and detector move parallel in the same direction, the system acquires projection images at various angles by rotating the tube-detector assembly around the patient, then segments these images for reconstruction into sectional views.
Solution Approach 2:
The patent transitions from 2D projection images to 3D sectional images through reconstruction processing. By acquiring projection data from multiple angles and applying tomographic reconstruction algorithms, the system generates cross-sectional images that provide depth information and internal structure visualization beyond what single-angle projection images can offer.
3Area of stationary object
If a flat panel detector is used to increase the field of view, then the detecting plane area is increased, but the resolution still decreases at acute or obtuse projection angles
Solution Approach 1:
The patent inverts the conventional scanning geometry by maintaining the projection angle at substantially 90 degrees to the patient's body axis throughout the scanning process. This is achieved by moving the X-ray tube and detector parallel to each other in the same direction while keeping the radiation axis perpendicular to the body axis, thereby maintaining optimal resolution across the entire field of view regardless of detector size.
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 enables the acquisition of sectional images with a longer field of view in the longitudinal direction, maintaining consistent projection angles and improving diagnostic capabilities for large-range 3D imaging and pathological assessments.
Implementation Method 1
a radiation emitting device for emitting radiation toward a patient, and a radiation detecting device for detecting radiation transmitted through the patient
Data Source
AI summary
An X-ray tube and a flat panel X-ray detector (FPD) are constructed movable parallel to each other in the same direction along a body axis which is a longitudinal direction of a patient. The X-ray tube intermittently emits radiation and the FPD detects radiation transmitted through the patient irradiated intermittently whenever the X-ray tube and FPD move every pitch. X-ray images O1, O2, . . . , OI, . . . , and OM are decomposed for every pitch noted above. The decomposed images are composed for each projection angle to obtain projection images P1, P2 and so on. Therefore, a sectional image with a long field of view in the longitudinal direction can be obtained by carrying out a reconstruction process based on the composed projection images.