X-Ray Focus Control in Breast Tomosynthesis to Prevent Image Blur

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Solution Overview

Problem

Digital breast tomosynthesis systems face blurring issues due to the movement of the X-ray tube, resulting in lower sharpness and quality of three-dimensional images, as existing methods require complex control of individual X-ray tube elements, increasing costs and implementation difficulties.

Innovation Solution

A digital breast tomosynthesis system that includes a focal spot controller to rotate the X-ray tube about a secondary axis, opposing the movement direction of the X-ray tube, thereby maintaining a fixed spatial position of the focal spot relative to the X-ray detector, using a C-arm configuration to control the focal spot's position during rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the x-ray tube is tilted to correct geometric magnification, then image accuracy is improved, but the x-ray focus position shifts causing defocus and reduced image quality

Engineering Contradiction:
Improveimage accuracyVSAvoidimage quality
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a dynamic adjustment system where the x-ray tube tilt angle and focus position are continuously coordinated. The focus position is dynamically adjusted based on the tilt angle to maintain optimal focus on the detector plane, resolving the contradiction between achieving geometric correction through tilting and maintaining image quality through proper focus.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes multiple parameters simultaneously - both the tilt angle and the focus position are adjusted together. By changing the focus position parameter in response to tilt angle changes, the system maintains the focus-detector relationship while achieving geometric correction, thus improving image accuracy without sacrificing image quality.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the x-ray tube is tilted to correct geometric magnification, then image accuracy is improved, but the focal spot position shifts causing defocus

Engineering Contradiction:
Improvegeometric magnification correctionVSAvoidfocal spot position
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The focus position is dynamically adjusted as the tilt angle changes. This dynamic coordination ensures that the focal spot remains properly positioned relative to the detector plane, correcting geometric magnification while maintaining focal spot precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback control where the focus position is adjusted based on the tilt angle. This feedback mechanism ensures that any shift in focal spot position caused by tilting is compensated, maintaining manufacturing precision while achieving geometric correction.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If the x-ray tube is tilted, then image accuracy is improved, but the x-ray beam focus position shifts

Engineering Contradiction:
Improveimage accuracyVSAvoidfocus control mechanism
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The focus control mechanism dynamically adjusts the focus position in response to tilt angle changes. This dynamic control, while adding some complexity, enables the system to maintain image accuracy by automatically compensating for focus position shifts caused by tilting.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system coordinates changes in multiple parameters - tilt angle and focus position - to achieve the desired image accuracy. By changing both parameters together in a controlled manner, the system improves image accuracy while managing device complexity through integrated control.

Inventive Principle:
Principle #35Parameter changes

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 simplifies the control of the focal spot's position, eliminating blurring and significantly improving the sharpness of projection images, which enhances the quality of three-dimensional images acquired.

Implementation Method 1

a x-ray tube (220) having an anode (221) and a cathode (222)

Methodology Applied
Scientific EffectX-ray generation: X-Ray

Data Source

PatentEP3797694B1Digital breast tomosynthesis device capable of controlling position of x-ray focus
Publication Date: 2024.03.06 MEDI FUTURE INC
  • EP3797694B1 patent drawingFigure 1
  • EP3797694B1 patent drawingFigure 2
  • EP3797694B1 patent drawingFigure 3~4

AI summary

Disclosed is a digital breast tomosynthesis system including: an X-ray tube configured to generate X-rays; a C-arm configured to receive the X-ray tube and rotate about a first rotation axis during an X-ray exposure period; an X-ray detector configured to convert the X-ray, which is emitted from the X-ray tube and passes through a breast, into image information; and a focal spot controller configured to operate in conjunction with a movement of the X-ray tube caused by a rotation of the C-arm, in which the focal spot controller controls a position of a focal spot of the X-ray with various methods such as a method of rotating the X-ray tube about a second rotation axis in the C-arm. As a result, the position of the focal spot of the X-ray tube may be controlled by the simple structure and method, thereby eliminating blurring of a projection image that affects the determination of quality of a three-dimensional image, and thus significantly improving sharpness.