X-ray Shielding Glass Composition for Medical Imaging
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Solution Overview
Problem
Existing X-ray shielding glasses lack sufficient shielding capability against X-rays with a tube voltage of 150 kV or less, and often have low visible light transmissivity or are colored, making them unsuitable for medical and research applications.
Innovation Solution
A glass composition comprising 15-25 mass% B2O3, 7-50 mass% La2O3, 7-50 mass% Gd2O3, 10-25 mass% WO3, with a total content of La2O3 and Gd2O3 being 45-65 mass%, and excluding ZnO, achieving high X-ray shielding performance and visible light transmissivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead glass with high density is used to achieve high X-ray shielding capability, then radiation shielding capability is improved, but environmental safety deteriorates due to toxic lead components
Solution Approach 1:
The patent removes lead components from the glass composition entirely, extracting the harmful substance while maintaining shielding capability through alternative heavy metal oxides (Bi2O3, WO3, PbO in controlled amounts, TiO2, ZrO2, Nb2O5, Ta2O5, MoO3, ThO2, UO2) combined with specific rare earth oxide content (La2O3, CeO2, Pr6O11, Nd2O3, Sm2O3, Gd2O3, Dy2O3, Er2O3, Yb2O3, Lu2O3 totaling 40-80 mass%).
Solution Approach 2:
The patent creates a composite glass material combining multiple heavy metal oxides and rare earth oxides to achieve the desired density and shielding properties without relying on lead alone, distributing the shielding function across multiple components that also contribute to chemical durability and optical properties.
2Reliability
If glass with high lead component content is used to achieve high shielding capability, then radiation shielding capability is improved, but surface cleaning performance deteriorates causing dimming and staining
Solution Approach 1:
The patent reduces or eliminates lead component content from the glass composition, removing the root cause of surface cleaning problems (dimming and staining) while maintaining shielding capability through alternative oxide combinations including Bi2O3, WO3, TiO2, ZrO2, and rare earth oxides.
3Ease of manufacture
If glass containing lower molar weight components (ZnO, TiO2, Li2O) is used, then ease of manufacture is improved, but X-ray shielding capability deteriorates
Solution Approach 1:
The patent changes the compositional parameters by limiting lower molar weight components (ZnO: 0-10 mass%, TiO2: 0-20 mass%, Li2O: 0-10 mass%) and compensating with higher proportions of heavy metal oxides (Bi2O3: 10-40 mass%, WO3: 5-30 mass%, PbO: 0-20 mass%) and rare earth oxides (40-80 mass% total), thereby maintaining both manufacturability and enhanced X-ray shielding capability.
4Illumination intensity
If glass is made with high visible light transmissivity is pursued, then transparency is improved, but X-ray shielding capability may deteriorate
Solution Approach 1:
The patent employs a composite glass system combining heavy metal oxides for shielding with specific rare earth oxides (La2O3, CeO2, Pr6O11, Nd2O3, Sm2O3, Gd2O3, Dy2O3, Er2O3, Yb2O3, Lu2O3) that can be tuned to maintain visible light transmissivity while providing the necessary X-ray attenuation through the heavy metal content (Bi2O3, WO3, PbO, TiO2, ZrO2, Nb2O5, Ta2O5, MoO3, ThO2, UO2).
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 glass provides high shielding capability against X-rays with a tube voltage of 150 kV or less, maintaining high visible light transmissivity and chemical durability, with a density of 5.00 g/cm3 or more and a refractive index of 1.855 or less.
Implementation Method 1
The shielding capability is proportional to the mass absorption coefficient and the density of glass
Data Source
AI summary
Provided is an X-ray shielding glass having high shielding capability against X-rays with a tube voltage of 150 kV or less. The X-ray shielding glass has a composition including: 15 mass% to 25 mass% B2O3; 7 mass% to 50 mass% La2O3; 7 mass% to 50 mass% Gd2O3; 10 mass% to 25 mass% WO3; 0 mass% to 7 mass% SiO2; 0 mass% to 10 mass% ZrO2; 0 mass% to 8 mass% Nb2O5; 0 mass% to 10 mass% Ta2O5; 0 mass% to 5 mass% Bi2O3; 0 mass% to 3 mass% CeO2; and 0 mass% to 1 mass% Sb2O3, wherein the glass contains no ZnO, the total content of La2O3 and Gd2O3 is 45 mass% to 65 mass%, and when the thickness of the glass is 3 mm, the transmittance of the glass to an X-ray from an X-ray tube with a tube voltage of 60 kV is 0.0050 % or less, and the transmittance of the glass to an X-ray from an X-ray tube with a tube voltage of 100 kV is 0.1500 % or less.