Double Displaced CT Geometry for Expanded Field of View
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional CT systems face challenges in reducing the physical size of detectors while maintaining image quality and simplifying system construction, particularly with the increasing complexity and cost of multi-slice systems.
Innovation Solution
The implementation of a double displaced CT acquisition geometry, where both the x-ray source and detector are displaced from the imaging isocenter, with an anti-scatter grid and varying displacement configurations to optimize detector utilization and FOV, allowing for adjustable angular sampling between 180° and 360°.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a larger detector is used to achieve a given transverse FOV, then the FOV coverage is improved, but the detector size and system complexity increase
Solution Approach 1:
The patent introduces a longitudinal displacement dimension in addition to the traditional transverse detector positioning. By displacing the detector array longitudinally from the imaging isocenter, the system achieves a larger transverse FOV without increasing detector size, as the longitudinal offset creates a geometric expansion of the effective FOV.
Solution Approach 2:
The patent employs asymmetric positioning where the detector array is displaced longitudinally by a distance different from the source displacement, creating an optimized geometric configuration. This asymmetric arrangement allows the detector to capture a wider transverse FOV while maintaining appropriate sampling geometry, resolving the contradiction between FOV size and detector dimensions.
2Area of stationary object
If the detector is shifted to achieve a larger transverse FOV, then the FOV is improved, but the angular sampling range increases to approximately 360°
Solution Approach 1:
The patent implements dynamic adjustment capabilities where the source and detector displacements can be varied to optimize the balance between transverse FOV and angular sampling range. By making the geometric configuration adjustable, the system can adapt to different imaging requirements, reducing the angular sampling range when possible while maintaining adequate FOV coverage.
3Productivity
If both source and detector are displaced from the imaging isocenter, then detector utilization is optimized, but the system construction complexity increases
Solution Approach 1:
The patent designs the double displacement geometry to serve multiple functions: optimizing detector utilization, achieving larger transverse FOV, and maintaining appropriate sampling geometry. This multi-functional geometric configuration reduces the need for additional components or complex mechanical adjustments, as the displacement itself accomplishes multiple objectives simultaneously.
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 a larger transverse Field of View (FOV) with reduced detector size, simplified system construction, and improved image quality by optimizing detector placement and angular sampling, thereby addressing the limitations of full and half beam geometries.
Implementation Method 1
An x-ray source 102 and an x-ray sensitive detector 104 are disposed on opposite sides of an examination region 106
Implementation Method 2
The source 102 emits radiation 112 which traverses the examination region 106 and is detected by the detector 104
Implementation Method 3
an anti-scatter grid and varying displacement configurations to optimize detector utilization and FOV
Data Source
Figure 1A~1B
Figure 2
Figure 3~4
AI summary
A computed tomography acquisition geometry provides an increased field of view (218). A radiation source (202, 702) such as an x-ray source and a radiation detector (204, 704) are displaced from the imaging center (214). In one implementation, the central ray (216) of a radiation beam (212) is parallel to the plane of the detector (204, 704) at the detector midpoint (219, 719), but is displaced from the imaging center.