X-Ray Collimator Angle Sensing With Resistive Strip Feedback

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Solution Overview

Problem

Existing X-ray systems lack accurate rotational angle measurement for rotatable collimators, leading to potential misalignment and increased radiation exposure due to incorrect amplimat chamber positioning.

Innovation Solution

A rotational angle measurement device comprising a resistive strip and plunger attached to the X-ray collimator, which generates an electrical signal indicative of the rotational angle through relative movement during collimator rotation, combined with a processing device for calibration and angle determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If rotational angle measurement is not implemented, then the system structure remains simple, but measurement precision and reliability deteriorate leading to potential misalignment and increased radiation exposure

Engineering Contradiction:
Improverotational angle measurement precisionVSAvoidmeasurement device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical angle measurement systems with an electrical measurement approach using a resistive strip and plunger. The resistive strip is attached to the rotating collimator assembly while the plunger remains stationary, and their relative movement generates electrical signals that directly indicate rotational angle, eliminating the need for complex mechanical encoders or potentiometers.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The resistive strip acts as an intermediary element between the rotating collimator assembly and the stationary plunger. As the collimator rotates, the resistive strip moves relative to the plunger, and this intermediate element converts the mechanical rotation into measurable electrical resistance changes that can be processed to determine the rotational angle.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If accurate rotational angle measurement is implemented, then reliability improves by preventing misalignment, but device complexity increases

Engineering Contradiction:
Improvecollimator positioning reliabilityVSAvoidmeasurement system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical angle measurement systems with an electrical measurement approach using a resistive strip and plunger. The resistive strip is attached to the rotating collimator assembly while the plunger remains stationary, and their relative movement generates electrical signals that directly indicate rotational angle, eliminating the need for complex mechanical encoders or potentiometers.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The measurement device provides real-time feedback about the collimator's rotational position through electrical signals generated by the resistive strip-plunger interaction. This feedback mechanism ensures that the system continuously monitors and can respond to positional deviations, maintaining reliable alignment between the X-ray source, collimator, and detector throughout the examination process.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If complex measurement devices are used, then measurement precision improves, but ease of manufacture deteriorates

Engineering Contradiction:
Improverotational angle measurement precisionVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces complex mechanical angle measurement systems with an electrical measurement approach using a resistive strip and plunger. The resistive strip is attached to the rotating collimator assembly while the plunger remains stationary, and their relative movement generates electrical signals that directly indicate rotational angle, eliminating the need for complex mechanical encoders or potentiometers.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The resistive strip is a simple, inexpensive component that can be easily manufactured and replaced if needed. Rather than using expensive precision mechanical components, the patent employs this straightforward electrical element that provides sufficient measurement precision for clinical purposes while significantly reducing manufacturing complexity and cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

Enables precise collimator rotation feedback, reducing the risk of incorrect radiation dosage measurement and optimizing collimation to minimize unnecessary radiation exposure.

Implementation Method 1

The plunger is arranged to be in contact with the elongated strip such that a rotation of the rotatable X-ray collimator moves the elongated strip relative to the plunger to produce an electrical signal indicative of a rotational angle of the rotatable X-ray collimator

Methodology Applied
Scientific EffectResistive strip effect: Electrical Resistance

Data Source

PatentEP4611641B1A novel and cost-effective way to measure collimator rotational angle in all three axis
Publication Date: 2025.12.03 KONINKLIJKE PHILIPS NV
  • EP4611641B1 patent drawingFigure 1
  • EP4611641B1 patent drawingFigure 2A~2B
  • EP4611641B1 patent drawingFigure 3A~3B

AI summary

The present invention relates to the field of radiation based imaging. In particular the invention relates to the field of X-ray collimation. In order to reduce the risk of wrong amplimat chamber position which may result into additional dose to patient, there is provided a rotational angle measurement device (10) for measuring a rotational angle of a rotatable X-ray collimator. The rotational angle measurement device (10) comprises a resistive strip (12), and a plunger (14). The resistive strip (12) comprises an elongated tape (15) that is attached to a first portion (60) of the rotatable X-ray collimator, and an longitudinal extent (LA) of the elongated tape (15) is arranged to be curved about the rotation axis of the rotatable X-ray collimator. The plunger (12) is attached to a second portion (40) of the X-ray collimator. The first portion and the second portion are arranged to rotate relative to each other during a rotation of the X-ray collimator. The plunger (12) is arranged to be in contact with the elongated strip (15) such that a rotation of the rotatable X-ray collimator moves the elongated strip (15) relative to the plunger to produce an electrical signal indicative of a rotational angle of the rotatable X-ray collimator.