Tomography Motion Compensation via Projection Surface Segmentation

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Solution Overview

Problem

Existing tomography systems struggle to accurately compensate for non-rigid movements, such as deformations caused by breathing, which lead to inconsistent image reconstruction during the computation of volume models.

Innovation Solution

The method divides the projection surface into partial surfaces, each with its own correction vector, allowing for independent displacement and compensation of deformations, using algebraic reconstruction techniques and optimization criteria like entropy minimization to improve image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single correction vector is used for the entire projection surface, then the device complexity is reduced, but the manufacturing precision and ability to compensate for non-rigid movements deteriorates

Engineering Contradiction:
Improvecorrection vector systemVSAvoidmotion compensation precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The projection surface is divided into multiple partial surfaces, and each partial surface is assigned its own correction vector. This segmentation allows independent correction of different regions of the projection surface, enabling precise compensation for non-rigid movements while maintaining manageable system complexity through modular correction approach.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If the projection surface is divided into multiple partial surfaces with independent correction vectors, then the motion compensation precision is improved, but the device complexity increases

Engineering Contradiction:
Improvemotion compensation precisionVSAvoidcorrection vector system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The projection surface is divided into multiple partial surfaces, and each partial surface is assigned its own correction vector. This segmentation allows independent correction of different regions of the projection surface, enabling precise compensation for non-rigid movements while maintaining manageable system complexity through modular correction approach.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If correction vectors are optimized iteratively using optimization criteria, then the image quality and sharpness are improved, but the computation time and productivity are reduced

Engineering Contradiction:
Improveimage qualityVSAvoidcomputation speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

An optimization criterion based on image entropy is employed to iteratively adjust the correction vectors. The entropy of the reconstructed volume model is calculated, and correction vectors are updated to minimize this entropy, creating a feedback loop that continuously improves image quality and sharpness while achieving accurate motion compensation.

Inventive Principle:
Principle #23Feedback

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 effectively compensates for non-rigid movements, reducing imaging distortions and improving the sharpness of volume models by iteratively optimizing correction vectors, resulting in clearer and more accurate representations of body structures.

Implementation Method 1

radiation, for example X-rays, is projected through the body volume, that is to say for example the patient, onto radiation sensors of a detector in the form of beam bundles

Methodology Applied
Scientific EffectX-ray absorption: Absorption (EM radiation)

Implementation Method 2

Each radiation sensor generates a pixel value

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS10512441B2Computed tomography having motion compensation
Publication Date: 2019.12.24 SIEMENS HEALTHINEERS AG
  • US10512441B2 patent drawing
  • US10512441B2 patent drawing
  • US10512441B2 patent drawing

AI summary

The embodiments relate to a method for producing a digital volume model of a body volume by a sensor device, which sensor device includes a plurality of radiation sensors, of which each produces a pixel value in a projection. In order to produce the volume model, a plurality of projections from different projection angles (a) are produced and the volume model is computed from sensor positions of the radiation sensors and pixel values of the radiation sensors. For at least one projection angle (a), the sensor positions are corrected by a respective correction vector for rigid motion compensation. The problem addressed is that of also compensating the non-rigid motion of the body volume (i.e., the deformation) in the computation of the volume model. This problem is solved in that, in order to correct the sensor positions, the projection surface provided by the totality of the radiation sensors is divided into a plurality of sub-surfaces and a separate correction vector is determined for each of the sub-surfaces independently of each other.