Radiation Imaging System Energy Subtraction for Motion Artifacts
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Solution Overview
Problem
Current radiation imaging systems using flat panel detectors face artifacts when moving objects, such as stents or calcified substances, are present during digital subtraction angiography, due to differences in images taken at varying radiation energies.
Innovation Solution
An imaging control apparatus and method that obtains multiple images at different radiation energies during a single shot, performs energy subtraction processing, and generates difference images using a two-dimensional detector that samples radiation multiple times between resets, allowing for accurate separation of bone and soft tissue images without artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If digital subtraction angiography is performed using images at varying radiation energies, then vascular diagnosis capability is improved, but motion artifacts are generated when moving objects are present
Solution Approach 1:
The imaging process is segmented into multiple energy levels (first energy level and second energy level) with separate mask images and live images acquired at each energy level. Energy subtraction processing is independently performed for each energy level, and the results are combined to generate the final difference image. This segmentation allows motion artifacts to be reduced while maintaining vascular diagnosis capability.
Solution Approach 2:
The radiation energy parameter is changed between mask image acquisition and live image acquisition. By acquiring images at different energy levels and performing energy subtraction, the patent eliminates the requirement for strict temporal synchronization between mask and live images, thereby reducing motion artifacts caused by subject movement during the imaging process.
2Measurement precision
If multiple images at different radiation energies are obtained during one shot, then energy subtraction processing accuracy is improved, but imaging time and system complexity increase
Solution Approach 1:
The patent merges mask image acquisition and live image acquisition into a single imaging shot, where both mask and live images at multiple energy levels are acquired continuously without interruption. This combining approach maintains high energy subtraction processing accuracy while minimizing the total imaging time by eliminating the need for separate imaging sessions.
Solution Approach 2:
The imaging process maintains continuous radiation emission and detector operation throughout the acquisition of all mask and live images at different energy levels. This continuous operation eliminates idle time between acquisitions and ensures that the subject remains in a consistent state, thereby maintaining high processing accuracy without significant time loss.
3Measurement precision
If a two-dimensional detector performs sampling multiple times between resets, then image separation precision is improved, but device complexity and processing load increase
Solution Approach 1:
The two-dimensional detector performs periodic sampling at predetermined time intervals during the radiation emission period, with each sampling cycle synchronized to the radiation pulse. The detector is reset periodically between sampling cycles. This periodic sampling approach enables precise separation of images at different energy levels while maintaining a manageable device complexity through regular, predictable operation patterns.
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 artifact-free imaging of moving targets by effectively subtracting background images, allowing for precise vascular diagnosis and reducing motion artifacts in radiography.
Implementation Method 1
a two-dimensional detector performs sampling at least twice during a period between two consecutive resets
Implementation Method 2
irradiating a subject with radiation whose energy changes during one shot
Implementation Method 3
a plurality of images at different energies are first obtained, for example, by emitting radiation at different tube voltages a plurality of times. As a result of performing computation of these images, it is possible to perform processing such as processing for separating a bone image and a soft tissue image
Data Source
AI summary
An imaging control apparatus obtains a plurality of images at different radiation energies, the images having been obtained as a result of irradiating a subject with radiation whose energy changes during one shot, and detecting, a plurality of times, the radiation that has passed through the subject during the one shot; generates an energy subtraction image by performing energy subtraction processing using a plurality of images; and generates a difference image using a plurality of generated energy subtraction images.