Offset Scanning X-ray Tomography for Compact Imaging

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Solution Overview

Problem

Current tomographic X-ray imaging technologies, such as CBCT, face challenges with large and expensive detectors, which limit the miniaturization of devices and result in increased radiation exposure to patients without improving image quality.

Innovation Solution

The method involves using a smaller X-ray detector and source by offsetting the X-ray source and detector relative to the rotation center, allowing for 180-degree scanning instead of 360-degree, and combining image information from different offsets to produce three-dimensional images, reducing radiation exposure and maintaining image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a large surface area X-ray detector is used to improve field of view, then the field of view is enlarged, but the device size and cost increase

Engineering Contradiction:
Improvedetector surface areaVSAvoiddevice size
Core Design Contradiction:
Area of stationary objectVSVolume of stationary object

Solution Approach 1:

The patent applies offset scanning where the rotation center is deliberately positioned asymmetrically relative to the detector surface, specifically at a distance of 0.5-2.0 times the detector width from the detector surface. This asymmetric configuration allows a smaller detector to capture a larger effective field of view by utilizing the geometric relationship between the offset rotation center and detector positioning, thereby resolving the contradiction between detector area and device size.

Inventive Principle:
Principle #4Asymmetry

2Area of stationary object

If a large surface area X-ray detector is used to improve field of view, then the field of view is enlarged, but the cost increases

Engineering Contradiction:
Improvedetector surface areaVSAvoiddevice cost
Core Design Contradiction:
Area of stationary objectVSEase of manufacture

Solution Approach 1:

By implementing offset scanning with the rotation center positioned at 0.5-2.0 times the detector width from the detector surface, the system achieves an enlarged field of view using a smaller, less expensive detector. This asymmetric geometric configuration reduces the required detector area while maintaining or improving imaging capabilities, thereby reducing device cost.

Inventive Principle:
Principle #4Asymmetry

3Area of stationary object

If a large surface area X-ray detector is used to improve field of view, then the field of view is enlarged, but the X-ray source requirements increase

Engineering Contradiction:
Improvedetector surface areaVSAvoidX-ray source quality requirements
Core Design Contradiction:
Area of stationary objectVSPower

Solution Approach 1:

The offset scanning configuration with rotation center at 0.5-2.0 times detector width from detector surface creates a geometric arrangement where the X-ray beam utilizes the detector more efficiently. This reduces the demand on the X-ray source to maintain uniform quality across a large detector area, as the effective imaging geometry is optimized through the asymmetric offset positioning.

Inventive Principle:
Principle #4Asymmetry

4Area of stationary object

If offset scanning is performed to enlarge field of view, then the field of view is enlarged, but 360 degree scanning is required increasing device size

Engineering Contradiction:
Improvefield of viewVSAvoiddevice size
Core Design Contradiction:
Area of stationary objectVSVolume of stationary object

Solution Approach 1:

The patent implements a specific asymmetric offset configuration where the rotation center is positioned at 0.5-2.0 times the detector width from the detector surface. This optimized offset allows effective field of view enlargement without requiring complete 360-degree scanning, as the asymmetric geometry provides sufficient angular coverage for tomographic reconstruction, thereby reducing device size.

Inventive Principle:
Principle #4Asymmetry

5Object-affected harmful factors

If radiation dose is reduced while maintaining field of view, then radiation exposure is reduced, but image quality deteriorates

Engineering Contradiction:
Improveradiation doseVSAvoidimage quality
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The offset scanning with rotation center at 0.5-2.0 times detector width from detector surface optimizes the geometric efficiency of X-ray utilization. This asymmetric configuration improves the signal-to-noise ratio in the acquired projections, allowing for reduced radiation dose while maintaining image quality through more efficient use of the limited X-ray photons that reach the detector.

Inventive Principle:
Principle #4Asymmetry

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 successful tomographic X-ray imaging with smaller detectors without increasing device size, reducing radiation exposure, and enhancing image versatility, particularly in dental imaging by directing radiation from behind the patient, thus minimizing exposure to sensitive tissues.

Implementation Method 1

X-radiation is produced with an X-ray source (22), collimated by means of a collimator (24) to the object being imaged and the X-radiation that has been transmitted through the object is received with an X-ray detector (21)

Methodology Applied
Scientific EffectX-ray transmission: X-Ray

Data Source

PatentEP2344041B1Method and device for performing computed tomography x-ray imaging
Publication Date: 2019.12.25 PALODEX GROUP
  • EP2344041B1 patent drawingFigure 1
  • EP2344041B1 patent drawingFigure 2
  • EP2344041B1 patent drawingFigure 3

AI summary

A method, device and software for performing tomographic imaging with several offset values in such a way that: - the first imaging phase is performed by scanning at least a part of the object to be imaged by following the first arc of the first rotating movement to produce the first image information, - the offset of the imaging is changed between imaging phases during imaging, - at least one other imaging phase is performed with at least one changed offset to produce second image information of at least part of the object, - the said image information produced by different offsets is combined into three-dimensional image information.