Respiration-Correlated CT Dose Modulation During Redundant Phases

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Solution Overview

Problem

4D CT imaging is affected by image artefacts due to irregular breathing cycles, leading to insufficient data coverage and the need for repeated scans, thereby increasing the X-ray dose applied to the subject.

Innovation Solution

A method that determines data-redundant breathing phases during a respiration-correlated CT scan and applies redundancy modulation to reduce the X-ray dose by modulating the X-ray dose during these phases, ensuring that essential data is captured without unnecessary radiation exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the X-ray beam is kept on continuously to ensure complete data coverage for all breathing phases, then data sufficiency is maintained, but the X-ray dose applied to the subject increases

Engineering Contradiction:
Improvedata sufficiencyVSAvoidX-ray dose
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The X-ray beam is activated periodically based on the breathing cycle phase rather than continuously. The control unit switches the X-ray beam on during inhalation phases when data is most valuable and switches it off during exhalation phases where data redundancy occurs, thereby reducing overall radiation exposure while maintaining sufficient data for reconstruction

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

Different parts of the breathing cycle are treated differently regarding X-ray exposure. The inhalation phase receives full X-ray exposure to capture critical motion data, while the exhalation phase receives reduced or no exposure since the data is redundant, optimizing the local quality of data acquisition relative to radiation risk

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If the X-ray dose is reduced during data-redundant breathing phases, then radiation exposure is minimized, but data coverage may become insufficient

Engineering Contradiction:
ImproveX-ray doseVSAvoiddata coverage
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system continuously monitors the breathing cycle phase and uses this feedback to dynamically control X-ray beam activation. The control unit detects when the subject enters data-redundant exhalation phases and automatically reduces or suspends X-ray exposure during those specific periods, while maintaining full exposure during critical inhalation phases

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The X-ray exposure regime is made dynamic rather than static. The system adapts the X-ray beam activation in real-time based on the subject's breathing phase, switching between full exposure and reduced exposure modes according to the physiological state, thereby optimizing both safety and data quality

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4454567B1Reducing an x-ray dose applied on a subject during a respiration-correlated computed tomography scan
Publication Date: 2025.10.29 SIEMENS HEALTHINEERS AG
  • EP4454567B1 patent drawingFigure 1~2
  • EP4454567B1 patent drawingFigure 3~4
  • EP4454567B1 patent drawingFigure 5~6

AI summary

A computer-implemented method for reducing an X-ray dose (12) applied on a subject (5) during a respiration-correlated computed tomography scan, the method comprising the following steps: (a) during a beam-on period of the scan, determining the beginning of a data-redundant breathing phase; (b) during the data-redundant breathing phase, applying a redundancy modulation to the applied X-ray dose such that the X-ray dose is reduced during the data-redundant breathing phase; (c) determining the end of the data-redundant breathing phase; (d) at the end of the data-redundant breathing phase, continuing the scan without the redundancy modulation of the X-ray dose.