Radiation Tomography Gantry Deflection Correction

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Solution Overview

Problem

Current radiation tomography methods face challenges in accurately calculating three-dimensional data due to gantry deflection and scattered radiation interference, especially when imaging with multiple X-ray sources at non-uniform angles.

Innovation Solution

The method involves calculating precise radiating timings using imaging timing correction data related to gantry angles, measuring absolute angles, and applying weightings to X-ray images to reduce scattered radiation influence, ensuring accurate three-dimensional data reconstruction even with multiple radiation sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple X-ray sources are used to reduce imaging time, then productivity is improved, but measurement precision deteriorates due to scattered radiation interference

Engineering Contradiction:
Improveimaging speedVSAvoidthree-dimensional data accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

Multiple X-ray sources are operated in alternating periodic cycles, where each source radiates for a specific duration followed by a pause, allowing scattered radiation from one source to subside before the next source activates. This periodic operation maintains high imaging speed while reducing scattered radiation interference in the detected signals.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent converts the harmful scattered radiation into a beneficial timing reference by detecting scattered radiation peaks and using them to identify optimal pause intervals between source operations. The scattered radiation, normally a source of error, becomes a useful signal for synchronizing the alternating operation of multiple sources to minimize interference.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Device complexity

If gantry deflection is not corrected, then device complexity is reduced, but manufacturing precision deteriorates due to angle measurement errors

Engineering Contradiction:
Improvesystem simplicityVSAvoidimaging angle accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The system continuously monitors gantry deflection by detecting scattered radiation patterns and uses this feedback to dynamically adjust the operation timing of multiple X-ray sources. The scatter peak detection provides real-time information about gantry position, which is fed back to optimize the radiating timing and maintain angle measurement accuracy without requiring complex mechanical correction mechanisms.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If imaging timing is not corrected for gantry deflection, then ease of operation is improved, but measurement precision deteriorates

Engineering Contradiction:
Improveoperation simplicityVSAvoidimaging angle precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system performs self-correction by automatically detecting scattered radiation peaks and using these peaks to determine the actual gantry angle and adjust imaging timing accordingly. The scatter detection mechanism serves dual purposes: both as a marker for timing synchronization and as a self-calibration reference, eliminating the need for external complex correction systems while maintaining high precision.

Inventive Principle:
Principle #25Self-service

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 allows for more accurate three-dimensional data calculation by minimizing the impact of gantry deflection and scattered radiation, resulting in higher image quality and reduced imaging time.

Implementation Method 1

a radiation source 1411 which radiates radiation 1401

Methodology Applied
Scientific EffectX-ray radiation: X-Ray

Implementation Method 2

an X-ray detector 1412 which detects the radiation 1401 radiated from the radiation source 1411

Methodology Applied
Scientific EffectX-ray detection: X-Ray

Data Source

PatentEP2324768B1Radiation tomography method and radiotherapy system
Publication Date: 2021.11.24 HITACHI LTD
  • EP2324768B1 patent drawingFigure 1~2
  • EP2324768B1 patent drawingFigure 3~4
  • EP2324768B1 patent drawingFigure 5~6

AI summary

Aradiationtomographymethodof the present invention includes: calculating a radiating timing, with reference to imaging timing correction data relating a plurality of gantry angles to a plurality of imaging timing correction amounts, on the basis of an imaging timing at which a radiation source supported by a rotating traveling gantry is arranged at a predetermined imaging angle and an imaging timing correction amount, of the plurality of imaging timing correction amounts, related to a gantry angle at which the traveling gantry is arranged at the imaging timing; and calculating, on the basis of an X-ray image imaged with a radiation radiated from the radiation source at the radiating timing, three-dimensional data of the X-ray image of a subject. According to the radiation tomography method, the X-ray image imaged with the further accurately arranged radiation can be obtained even in a case where the traveling gantry deflects depending on the gantry angle at which the traveling gantry is arranged, and thus the three-dimensional data can be obtained more accurately.