High-pass Radiation Shield for Selective Photon Attenuation
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Solution Overview
Problem
In-plane Bi shielding during radiological examinations effectively reduces radiation dose to radiosensitive organs but degrades image quality, leading to concerns about diagnostic accuracy, and no efficient alternative has been introduced for in-plane shielding in radiological examinations like CT, radiography, fluoroscopy, and angiography.
Innovation Solution
A high-pass radiation shield with two sublayers, one comprising a first radiation attenuation material with an atomic number from 21 to 30 and the second with a different material, configured to selectively attenuate low-energy photons while allowing high-energy photons to pass through, reducing patient dose without degrading image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If in-plane Bi shielding is used to protect radiosensitive organs, then radiation dose to these organs is reduced, but image quality is degraded and artifacts are caused
Solution Approach 1:
The shield is divided into multiple sublayers with different materials and functions. The first sublayer uses high-Z material (Z≥56) for strong attenuation of low-energy photons, while the second sublayer uses low-Z material (Z<56) to attenuate secondary radiation without blocking diagnostic photons. This segmentation allows the shield to protect against harmful radiation while preserving image quality.
Solution Approach 2:
Different regions of the shield have different material compositions optimized for specific functions. The first sublayer is positioned closer to the radiation source and uses high-Z material for maximum attenuation of useless low-energy photons. The second sublayer is positioned farther from the source and uses low-Z material to attenuate secondary radiation while being transparent to diagnostic photons. This local differentiation of material properties resolves the contradiction between protection and image quality.
2Object-affected harmful factors
If thick lead garment is used for out-of-plane shielding, then all radiations with different energies are blocked, but the shield has no interference with image quality
Solution Approach 1:
The shield's material composition parameters are optimized to change the attenuation characteristics. By using a combination of high-Z and low-Z materials in specific layers, the shield achieves selective attenuation: strong blocking of low-energy photons while maintaining transparency to high-energy diagnostic photons. This parameter optimization allows the shield to protect without degrading image quality.
3Reliability
If in-plane shielding is used to reduce patient dose, then cancer risk to radiosensitive organs is reduced, but diagnostic accuracy is reduced due to image degradation
Solution Approach 1:
The multi-layer shield structure acts as an intermediary between the radiation source and the patient's radiosensitive organs. The first sublayer with high-Z material serves as the primary intermediary to block harmful low-energy photons. The second sublayer with low-Z material serves as a secondary intermediary to attenuate secondary radiation while preserving diagnostic photon transmission. This intermediary structure enables dose reduction while maintaining diagnostic accuracy.
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
The high-pass shield provides 20-55% dose reduction in radiosensitive organs during CT scans and 30-50% during other radiological examinations without causing image artifacts, maintaining image quality comparable to unshielded scans.
Implementation Method 1
The first sublayer is configured to partially attenuate a primary radiation beam emanating from a radiation source... The first sublayer is configured to block or highly attenuate a first range of energies of radiation... Low energy photons (useless photons) could not pass through the patient's body and hence contribute mostly on patient's dose rather than the signal to noise ratio (SNR)
Implementation Method 2
The second sublayer is configured to attenuate secondary radiations emanating from the first sublayer... The second sublayer is configured to block or attenuate a third range of energies of radiation... Secondary radiations 315 may be produced after the interaction of primary radiations 309 with the first radiation attenuation material 103
Data Source
AI summary
A high-pass radiation shield for using during radiological examinations is provided. The shield comprises: a first sublayer having a first radiation attenuation material of atomic number from 21 to 30; and a second sublayer having a second radiation attenuation material of atomic number 56 or greater. The weight of the second radiation attenuation material is not greater than the weight of the first radiation attenuation material. The shield is configured for placement on a patient's body over the entire or a portion of the field of view (FOV) for protection of the organs, especially radiosensitive organs against radiation dangers emitted by an X-ray tube without degrading image quality.