Parallax Correction for Movable Radiation Source Visualization
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Solution Overview
Problem
Current systems fail to accurately visualize the position of movable radiation sources, such as those used in brachytherapy, due to parallax issues between radiation sensors and cameras, especially when the source is small and mobile, leading to potential misplacement or loss during medical procedures.
Innovation Solution
An apparatus comprising a radiation sensor, a camera, a light diverter, and a composite image generator that automatically scales the radiation source marker's position to the camera image, using a pixelated radiation sensor with a coded aperture and a mirror to correct for parallax and maintain accurate visualization of movable radiation sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a radiation sensor and camera are used to visualize the radiation source position, then the source location can be detected, but parallax error occurs between the sensor axis and camera axis causing inaccurate positioning
Solution Approach 1:
A light diverter (mirror) is introduced as an intermediary component to redirect light from the radiation source to the camera while maintaining the radiation sensor's ability to detect radiation. This allows both devices to observe the same apparent source position without direct physical alignment, eliminating parallax error between the sensor axis and camera axis.
Solution Approach 2:
The light diverter changes the optical path dimension by reflecting light at an angle (typically 45 degrees), allowing the camera to view the radiation source from a different spatial dimension without requiring direct alignment with the radiation sensor axis. This dimensional change resolves the parallax conflict between the two detection axes.
2Object-affected harmful factors
If the radiation source is made small for implantable use, then patient safety and treatment precision are improved, but the source becomes difficult to locate visually if lost
Solution Approach 1:
The radiation source is equipped with a light emitter (such as an LED) that emits visible light in addition to radiation. This allows the source to be visually detected through the transparent or translucent catheter material when light is emitted, while maintaining its small implantable size. The light emission provides visual feedback for source location without increasing the radiation-emitting dimensions.
Solution Approach 2:
The catheter material acts as an intermediary that transmits both radiation and visible light from the small radiation source to external detectors and observers. The light diverter also serves as an intermediary that redirects visible light to the camera for visualization, enabling detection of the small source without increasing its physical size.
3Object-affected harmful factors
If the spindle is unwound remotely without visualization, then caregiver safety is improved by keeping them outside the shielded room, but the risk of source misplacement increases due to lack of visual feedback
Solution Approach 1:
The system provides real-time visual feedback through the composite image displayed on the monitor, showing the radiation source position overlaid on the camera view of the catheter. This feedback loop allows the caregiver to monitor source movement and position accurately while remaining outside the shielded room, maintaining both safety and reliability.
Solution Approach 2:
The radiation sensor output and camera image are merged into a single composite image that displays the radiation source position (detected by the sensor) overlaid on the visual field (captured by the camera). This combined visualization provides both radiometric and optical information simultaneously, enabling accurate source positioning monitoring without caregiver exposure.
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 real-time, accurate visualization of movable radiation sources, reducing the risk of misplacement and allowing for rapid localization of lost sources, thereby enhancing safety and precision in medical procedures.
Implementation Method 1
a light diverter arranged in front of the radiation sensor for diverting toward the camera light originally emitted toward the radiation sensor
Implementation Method 2
a radiation sensor having a sensor axis... arranged for generating an angular position, with respect to a sensor axis, of a radiation source emitting radiations
Data Source
AI summary
An apparatus for visualizing a movable radiation source, the apparatus comprising: a radiation angular position sensor arranged for generating an angular position, with respect to a sensor axis, of a radiation source emitting radiations in front of said radiation angular position sensor; a camera having a camera axis distinct from the sensor axis; a light diverter arranged in front of said radiation angular position sensor for diverting toward the camera, light originally emitted in front of said radiation angular position sensor toward the radiation angular position sensor, the light diverter being arranged to not change the direction of radiations emitted in front of said radiation angular position sensor; and a composite image generator arranged for adding to a camera image captured by the camera a radiation source marker at a position derived from said angular position and automatically scaled to the camera image size and resolution.