Radiotherapy Imaging Using Orthogonal Slice Extraction

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Solution Overview

Problem

Current radiotherapy systems face challenges in accurately targeting moving areas within a patient due to the time lag between imaging and treatment, particularly caused by patient movement during the prolonged process of acquiring multiple three-dimensional images.

Innovation Solution

The system uses two-dimensional or one-dimensional imaging slices oriented orthogonally to the radiation beam, allowing for continuous adjustment of the beam position and orientation, reducing the need for full three-dimensional imaging and thereby minimizing the delay between target motion and beam adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If full three-dimensional images are acquired through multiple slices, then the completeness of target region imaging is improved, but the image acquisition time increases

Engineering Contradiction:
Improveimaging completenessVSAvoidimage acquisition time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the essential imaging information needed for beam guidance by acquiring single or few two-dimensional slices rather than complete three-dimensional volumes. This selective extraction of critical target position data reduces acquisition time while maintaining sufficient precision for real-time beam adjustment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by acquiring only the minimum necessary imaging data (one or few slices) rather than complete three-dimensional coverage. This partial imaging approach provides sufficient information for beam targeting without the time penalty of comprehensive volumetric scanning.

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If multiple slices are acquired to build three-dimensional picture, then the accuracy of target localization is improved, but the delay between target motion and beam adjustment increases

Engineering Contradiction:
Improvetarget localization accuracyVSAvoidtime delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the critical positional information from the target region by acquiring minimal slice data rather than complete three-dimensional images. This extraction of essential localization data maintains sufficient accuracy for beam guidance while eliminating the time delay associated with comprehensive volumetric imaging.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent enables continuous useful action by acquiring images at high temporal resolution with single or few slices, allowing the system to continuously track target motion and adjust the beam in real-time without the intermittent delays caused by lengthy three-dimensional scanning cycles.

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If single slice imaging is used to reduce acquisition time, then the real-time tracking capability is improved, but the signal to noise ratio may be reduced

Engineering Contradiction:
Improveimage acquisition speedVSAvoidsignal to noise ratio
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by optimizing the thickness and orientation of the acquired slices to maximize signal-to-noise ratio within the constraint of rapid single-slice imaging. By carefully controlling imaging parameters such as slice thickness, gradient strength, and RF pulse characteristics, the system achieves high-quality images quickly.

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 significantly reduces the time required for image acquisition, enhancing the accuracy and speed of radiation delivery by maintaining a continuous match between the target position and radiation beam alignment, even as the patient moves.

Implementation Method 1

imaging is performed by applying an RF field in the presence of a magnetic field to a target region within a patient so that it reorients the spin of the nuclei of the atoms

Methodology Applied
Scientific EffectMagnetic resonance imaging: Electromagnetic Induction

Implementation Method 2

The position and orientation of these slices in the patient are defined by a magnetic gradient field, generated by a set of gradient coils

Methodology Applied
Scientific EffectMagnetic gradient field: Magnetic Field

Data Source

PatentEP2558162B1Radiotherapy and imaging apparatus
Publication Date: 2020.06.10 ELEKTA AB
  • EP2558162B1 patent drawingFigure 1
  • EP2558162B1 patent drawingFigure 2
  • EP2558162B1 patent drawingFigure 3~4

AI summary

A number of radiotherapy systems are disclosed, each having an integrated imaging apparatus to track movement of the target region and so guide the therapeutic radiation beam during treatment. Various systems are disclosed in which the imaging data obtained by the imaging apparatus is simplified, to reduce the data acquisition time and so improve the temporal resolution of the imaging system and consequently the accuracy of the radiation treatment.