Dual-layer X-ray detector for soft tissue motion tracking
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Solution Overview
Problem
Current radiation therapy techniques face challenges in accurately locating tumors due to motion of soft tissue organs, which can be obscured by bony structures, leading to inaccurate radiation delivery and increased imaging doses.
Innovation Solution
A dual-layer X-ray detector system with low-energy and high-energy sensors and an energy-separation filter allows for simultaneous X-ray imaging with different energy levels, enabling the generation of soft-tissue-only images by subtracting bony structure contributions, thereby enhancing motion detection accuracy without increasing patient exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fluoroscopy is used to obtain real-time moving images of target tissue, then motion tracking capability is improved, but bony structures occlude soft tissue making tracking challenging
Solution Approach 1:
The patent segments the imaging process into two distinct energy acquisitions (high energy and low energy) that are combined to separate soft tissue from bony structures. This segmentation allows independent optimization of each energy level for specific tissue types, resolving the occlusion problem.
Solution Approach 2:
The patent uses a composite imaging approach combining high-energy and low-energy X-ray images to create a composite soft-tissue-only image. This composite method leverages the different attenuation properties of tissues at different energies to isolate soft tissue signals from bone interference.
2Measurement precision
If multiple X-ray exposures are used to separate bones from soft tissues, then soft tissue visibility is improved, but patient imaging dose increases
Solution Approach 1:
The patent merges high-energy and low-energy image acquisitions into a single dual-energy imaging protocol. By capturing both energy levels in one imaging session and combining them through subtraction, the system achieves soft tissue separation without requiring multiple separate exposures, thereby reducing cumulative dose.
Solution Approach 2:
The patent changes the energy parameter of X-rays to achieve tissue differentiation. By acquiring images at two distinct energy levels and using logarithmic subtraction, the system extracts soft tissue information while minimizing the need for repeated high-dose exposures.
3Measurement precision
If time offset between high energy and low energy X-ray images is reduced, then motion blur is reduced, but image acquisition complexity increases
Solution Approach 1:
The patent implements a nested dual-layer detector structure where a low-energy detector is positioned in front of a high-energy detector. This nested configuration allows simultaneous acquisition of both energy levels without temporal offset, as the X-ray beam passes through the low-energy layer first, then the high-energy layer detects the transmitted photons.
Solution Approach 2:
The low-energy detector performs preliminary filtering of the X-ray beam, absorbing low-energy photons before they reach the high-energy detector. This preliminary action at the first layer enables the second layer to detect only higher-energy transmitted photons, achieving energy separation without temporal delay.
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 provides accurate and real-time motion tracking of soft tissue organs during radiation therapy, reducing the impact of bony structures and maintaining low imaging doses, thus improving the precision of radiation delivery.
Implementation Method 1
a low-energy X-ray scintillator that is operable to convert first incident X-rays into a first set of light photons
Implementation Method 2
a high-energy X-ray scintillator that is operable to convert transmitted X-rays into a second set of light photons
Implementation Method 3
an energy-separation filter that is operable to absorb or reflect at least a portion of the energy of transmitted X-rays and convert the first exit X-ray spectrum into a second exit X-ray spectrum
Data Source
AI summary
An imaging apparatus includes a first X-ray detector that includes: a low energy scintillator operable to convert an incident X-ray spectrum into a first set of light photons; a first light imaging sensor operable to generate a set of low energy image signals from the first set of light photons, wherein a first exit radiation is a remainder portion of the first incident radiation after the X-ray spectrum passes through the low energy scintillator and the first light imaging sensor; an energy-separation filter operable to absorb or reflect at least a portion of the energy of the first exit X-ray spectrum and convert the first exit X-ray spectrum into a second exit X-ray spectrum; a second X-ray detector that includes: a high energy scintillator operable to convert the second exit X-ray spectrum into a second set of light photons; a second light imaging sensor operable to generate a set of high energy image signals from the second set of light photons; and a processor configured to: generate a high-energy image that is based on the set of high energy image signals and a low-energy image that is based on the set of low energy image signals; and perform a comparison of the high-energy image from the low-energy image to generate a soft tissue image.