Vanadium-Doped Mixed Oxide Scintillator for CT Imaging
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Solution Overview
Problem
Current scintillators used in CT scanners, such as Gd2O2S doped with Pr and (Y, Gd)2O3 doped with Eu, suffer from high light scattering due to non-transparency and significant afterglow, which increases radiation dose and slows down scanning processes.
Innovation Solution
Development of a mixed oxide material (YwTbx)3Al5-yGayO12:Cez doped with vanadium (V), which reduces afterglow while maintaining high light yield, allowing for improved transparency and efficient photon detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If Gd2O2S doped with Pr is used as scintillator, then light yield is high, but transparency to visible light is poor causing light scattering and noise
Solution Approach 1:
The patent changes the chemical composition parameters of the scintillator material by incorporating specific ratios of Yttrium (Y) and Terbium (Tb) in the formula (YwTbx)3Al5-yGayO12, along with controlling Ga content, to achieve optimal balance between light yield and transparency. This compositional parameter optimization resolves the contradiction between high light output and visible light transparency.
Solution Approach 2:
The invention creates a composite scintillator material combining multiple elements (Y, Tb, Al, Ga, Ce) in a specific crystal structure (Y3Al5O12-based), where each component contributes different properties. The composite nature allows simultaneous achievement of high light yield from Ce doping and good transparency through the specific Y-Tb-Ga composition, resolving the contradiction between these opposing requirements.
2Object-affected harmful factors
If (Y, Gd)2O3 doped with Eu is used as scintillator, then transparency to visible light is improved, but afterglow increases slowing down scanning process
Solution Approach 1:
The patent optimizes compositional parameters by selecting specific w and x values in the (YwTbx)3Al5-yGayO12 formula to control the crystal field environment and luminescence characteristics. By adjusting the Y/Tb ratio and Ga content, the material achieves fast decay time (low afterglow) while maintaining good transparency, resolving the time-related contradiction.
Solution Approach 2:
The invention introduces localized structural modifications through Ga doping at specific lattice positions and Ce3+ ion substitution, creating localized luminescence centers with optimized emission and decay characteristics. This local quality enhancement at specific crystallographic sites allows fast response while maintaining overall material transparency.
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 vanadium-doped mixed oxide material significantly reduces afterglow and maintains high light yield, making it suitable for modern CT scanners with reduced radiation dose and faster scanning processes.
Implementation Method 1
scintillator materials that, in response to a stimulation by ionizing radiation such as X-rays, β- or γ-radiation, emit radiation with photons of considerably lower energy
Implementation Method 2
The second subunit comprises a photodetector which can detect the photons emitted by the scintillator or phosphor and produces corresponding electrical signals
Data Source
AI summary
The present invention relates to mixed oxide materials, methods for their preparation, detectors for ionizing radiation and CT scanners. In particular, a mixed oxide material is proposed having the formula (YwTbx)3Al5-yGayO12:Cez, wherein 0.01≦w≦0.99, 0.01≦x≦0.99, 0≦y≦3.5 and 0.001≦z≦0.10 and wherein w+x+3*z=1, whereby the mixed oxide material is doped with at least 10 ppm V.