Proton Beam Tracking via Multi-Angle X-Ray Fluoroscopy

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Solution Overview

Problem

Current radiation irradiating systems face challenges in accurately detecting tracking targets during X-ray fluoroscopy, especially when the target object is thick, leading to erroneous detections and increased irradiation time due to the need for manual re-detection.

Innovation Solution

A radiation irradiating system with multiple pairs of X-ray fluoroscopic devices and a control unit that calculates detection accuracy and correlation values from captured images to accurately detect the tracking target position and control radiation delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If template matching is used to detect tracking target position on fluoroscopic images, then detection automation is improved, but detection accuracy deteriorates under severe X-ray fluoroscopic conditions (thick target objects)

Engineering Contradiction:
Improvetracking target detection automationVSAvoidtracking target position detection accuracy
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent introduces an evaluation function as an intermediary mechanism that mediates between the template matching results and the final position determination. This evaluation function assesses multiple candidate positions and selects the most accurate one, thereby maintaining automation while improving detection accuracy under severe fluoroscopic conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a feedback mechanism where the evaluation function continuously assesses the quality of template matching results and adjusts the selection of tracking target position accordingly. By providing feedback on detection confidence and accuracy, the system can automatically correct or refine position detection even when initial template matching is ambiguous due to severe imaging conditions.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If manual re-detection is performed to correct erroneous tracking target detection, then detection accuracy is improved, but irradiation time increases

Engineering Contradiction:
Improvetracking target position detection accuracyVSAvoidirradiation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent enables the system to perform self-correction of detection errors through the evaluation function, which automatically identifies and corrects erroneous tracking target positions without requiring manual intervention. This self-service capability maintains high detection accuracy while eliminating the time loss associated with manual re-detection during irradiation.

Inventive Principle:
Principle #25Self-service

3Reliability

If multiple pairs of X-ray fluoroscopic devices are used to improve tracking target detection accuracy, then detection reliability is improved, but device complexity increases

Engineering Contradiction:
Improvetracking target detection reliabilityVSAvoidX-ray fluoroscopic device configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes multiple pairs of X-ray fluoroscopic devices to capture tracking target positions from multiple spatial dimensions and angles. By integrating information from different dimensional perspectives, the evaluation function can more reliably determine the accurate tracking target position, improving detection reliability through dimensional redundancy rather than simply adding more devices.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 enables accurate detection of tracking targets even under severe X-ray fluoroscopic conditions, reducing irradiation time and exposure dose by minimizing erroneous detections and automating the tracking process.

Implementation Method 1

two or more pairs of X-ray fluoroscopic devices configured to capture fluoroscopic images of a tracking target

Methodology Applied
Scientific EffectX-ray transmission and detection: X-Ray

Data Source

PatentEP3466488B1Radiation application system and moving body tracking apparatus
Publication Date: 2023.09.20 HITACHI LTD
  • EP3466488B1 patent drawingFigure 1
  • EP3466488B1 patent drawingFigure 2
  • EP3466488B1 patent drawingFigure 3~4

AI summary

A template matching is performed on two fluoroscopic images by using a template image prepared in advance and a position corresponding to a high matching score is listed as a candidate for the position of a marker 29. From two lists of the candidates of the position of the marker 29, the lengths of common vertical lines for all combinations are calculated. Then, the position of the marker 29 is detected based on the matching score and the common vertical line. Then, based on the detected position of the marker 29, an amount of a proton beam to be irradiated to a target is controlled. Therefore, a tracking target can be accurately detected even when the conditions for X-ray fluoroscopy is severe, e.g., a thick object.