Flat Panel Sensor Real-Time X-Ray Dose Control

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Solution Overview

Problem

Current radiography systems face challenges in real-time exposure control of X-rays, leading to risks of overexposure or underexposure, particularly due to the need for precise calibration and the limitations of existing Automatic Exposure Control (AEC) solutions, which are costly, cumbersome, and not suitable for mobile systems.

Innovation Solution

A method for real-time exposure control that utilizes a digital plane sensor to analyze signal levels in predetermined areas of interest, distinguishing between useful and parasitic signals without modifying the pixel matrix, and allows for wireless transmission of control signals to adjust X-ray doses, enabling accurate exposure without additional hardware modifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If external AEC device with ionization chamber is used, then real-time exposure control is achieved, but additional hardware cost and system complexity increase

Engineering Contradiction:
Improveexposure control precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the exposure control function from external hardware and relocates it to the detector's existing pixel matrix. By utilizing a dedicated region within the detector array and its inherent readout electronics, the system eliminates the need for separate ionization chambers and external control devices, thereby reducing system complexity while maintaining measurement precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The detector serves multiple functions: it acts as both the imaging device and the exposure control sensor. The same pixel matrix that captures the radiographic image also measures the exposure dose through a dedicated region, eliminating the need for separate specialized hardware and reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If external AEC device is used, then exposure control is achieved, but additional cost of at least €500 per unit is incurred

Engineering Contradiction:
Improveexposure control precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the exposure control function with the imaging detector by allocating a dedicated region within the pixel matrix for dose measurement. This integration eliminates the need for separate external AEC devices, thereby reducing manufacturing costs while maintaining exposure control precision through shared hardware resources.

Inventive Principle:
Principle #5Merging (Combining)

3Extent of automation

If internal AEC with pixel matrix modification is used, then real-time control signal is provided, but device complexity and calibration difficulty increase

Engineering Contradiction:
Improveautomation of exposure controlVSAvoidpixel matrix complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent applies local quality by designating a specific dedicated region within the pixel matrix for exposure measurement, while the remaining pixels continue their standard imaging function. This localized approach enables automated real-time control signals without requiring modification of the entire pixel matrix, thereby reducing overall device complexity.

Inventive Principle:
Principle #3Local quality

4Measurement precision

If Preshot device is used, then preliminary exposure assessment is made, but real-time control signal is not provided and delay occurs

Engineering Contradiction:
Improveexposure assessment accuracyVSAvoidexposure control delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements continuous exposure monitoring during the entire exposure process by repeatedly reading the dedicated region of the pixel matrix. This continuous measurement provides real-time control signals throughout the exposure, eliminating the time delay inherent in preliminary preshot assessments while maintaining accurate exposure assessment.

Inventive Principle:
Principle #20Continuity of useful action

5Measurement precision

If external sensor is placed in front of imager, then exposure measurement is achieved, but additional dose to patient is absorbed

Engineering Contradiction:
Improveexposure measurement accuracyVSAvoidpatient radiation dose
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The detector performs self-measurement of the exposure dose by utilizing a dedicated region within its own pixel matrix. This self-service approach eliminates the need for external sensors that would require placement in the X-ray beam path, thereby avoiding additional patient radiation dose while maintaining accurate exposure measurement.

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 method ensures optimal patient exposure by accurately differentiating between useful and parasitic signals, allowing for real-time dose adjustments, reducing the risk of overexposure, and enabling its use in both fixed and mobile radiography systems without the need for extensive calibration or additional hardware.

Implementation Method 1

a set of pixels organized in a matrix according to rows and columns and configured to generate signals as a function of the dose of X-rays striking the detector

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3984461B1Method for monitoring the real-time exposure of a dose of x-rays
Publication Date: 2024.06.12 TRIXELL S
  • EP3984461B1 patent drawingFigure 1~2
  • EP3984461B1 patent drawingFigure 3~4
  • EP3984461B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for real-time exposure control of an X-ray dose emitted by an X-ray beam generating tube and received by a detector comprising a flat panel sensor having an array of pixels arranged in a matrix according to rows and columns and configured to generate signals as a function of the X-ray dose striking the detector, the generating tube comprising a control block of the generating tube configured to control an emitted X-ray dose, said control method being characterized in that it comprises the following steps: - exposure (100) of the flat panel sensor to an X-ray dose emitted by the X-ray beam generating tube; - repeated reading (101) of at least one of the pixel rows during the exposure of the flat panel sensor to the X-ray dose; - determination (102) of a useful signal and a spurious signal from the signals resulting from the reading of at least one of the rows;- transmission (103) of the useful signal to the control block of the generator tube.;