Magnetic Field Alignment for Portable X-Ray Imaging
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Solution Overview
Problem
Portable radiography systems face challenges in aligning the radiation source with the image receiver, particularly when the receiver is hidden behind the patient, as existing methods require direct line-of-sight alignment, are not adaptable to variable source-to-image distances, and do not provide sufficient information for adjusting the collimator to reduce backscatter, limiting image quality.
Innovation Solution
A method using a sensor and detector arrangement that generates a magnetic field with a predetermined pattern and time-varying vector direction to sense the distance and positional orientation of the receiver relative to the radiation source, providing output signals for alignment adjustments, which can be adapted for use with variable source-to-image distances and does not require visibility of the receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If visual assessment alignment is used in portable radiography systems, then the system maintains mobility and portability, but alignment precision deteriorates due to lack of mechanical constraints
Solution Approach 1:
The patent replaces mechanical alignment systems with electromagnetic field-based alignment. A magnetic field generator creates a reference field pattern, and magnetic field sensors detect this pattern to determine the radiation source position and orientation relative to the image receiver, enabling precise alignment without mechanical mounting arms or physical constraints.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the radiation source and image receiver for alignment purposes. The magnetic field serves as a reference that can be detected by sensors to calculate positional and orientational relationships, acting as a mediator that enables alignment without direct mechanical connection or visual line-of-sight.
2Difficulty of detecting and measuring
If direct line-of-sight alignment methods are used, then alignment can be achieved when receiver is visible, but the method fails when receiver is hidden behind the patient
Solution Approach 1:
The magnetic field acts as an intermediary that can penetrate the patient's body, allowing the alignment system to function regardless of whether the receiver is visible. The magnetic field generator creates a reference field that sensors can detect through the patient, enabling alignment calculations even when the receiver is positioned behind the patient.
Solution Approach 2:
The patent changes the alignment detection parameter from optical (visual line-of-sight) to magnetic field-based detection. This parameter change allows the system to detect the receiver position through the patient's body using magnetic field sensors, overcoming the limitation of direct visual alignment methods.
3Device complexity
If fixed source-to-image distance is assumed, then alignment calculation is simplified, but the system cannot adapt to variable distances
Solution Approach 1:
The patent makes the source-to-image distance a variable parameter rather than a fixed constant. The magnetic field-based detection system measures the actual distance between the radiation source and image receiver, allowing the alignment calculations to adapt to any distance while the control system guides the operator to achieve the optimal fixed distance for the specific imaging task.
Solution Approach 2:
The system provides feedback to the operator about the current alignment status and source-to-image distance. The control system calculates the optimal distance based on the imaging task and guides the operator to adjust the positioning, creating a feedback loop that achieves the desired fixed distance while adapting to the variable starting position.
4Ease of operation
If existing alignment methods are used, then current systems can be operated, but collimator adjustment information is insufficient for reducing backscatter
Solution Approach 1:
The magnetic field-based alignment system provides comprehensive feedback information about the radiation source position, orientation, and distance relative to the image receiver. This information includes the optimal collimator angle for minimizing backscatter, enabling the operator to adjust the collimator correctly while maintaining system operability with familiar control interfaces.
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 accurate alignment of the radiation source with the image receiver and anti-scatter grid, improving image quality by reducing backscatter and allowing for non-perpendicular radiation angles, while being suitable for retrofitting existing systems.
Implementation Method 1
a first transmitter apparatus that is energizable to generate, about itself, a magnetic field having a fixed-position field pattern and having a time-varying vector direction at a predetermined frequency
Implementation Method 2
a sensing apparatus with a plurality of sensor elements, each of the plurality of sensor elements providing a sensor signal at the predetermined frequency of the magnetic field
Data Source
AI summary
A method for aligning a radiation source with a portable image receiver in a radiographic imaging system generates a magnetic field with a predetermined field pattern and with a time-varying vector direction at a predetermined frequency from an emitter apparatus that is coupled to the radiation source, wherein the generated magnetic field further comprises a synchronization signal. Sensed signals from the magnetic field are obtained from a sensing apparatus that is coupled to the image receiver, wherein the sensing apparatus comprises three or more sensor elements, wherein at least two of the sensor elements are arranged at different angles relative to each other and are disposed outside the imaging area of the image receiver. An output signal is indicative of an alignment adjustment according to the amplitude and phase of the obtained sensed signals relative to the synchronization signal.