Wax Contrast Medium for Fine-Resolution X-Ray CT of Biological Samples
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Solution Overview
Problem
Existing X-ray CT methods struggle to provide sufficient contrast for biological samples due to low X-ray absorption by elements like hydrogen, carbon, and nitrogen, and conventional contrast agents often fail to penetrate adequately or cause excessive contrast, leading to poor image quality.
Innovation Solution
A method using a contrast agent comprising wax with a density of 0.95 g/cm3 or less and a melting point of 40° C. to 80° C. is introduced, which penetrates into the biological sample, is solidified, melted, and resolidified, allowing X-ray CT imaging with X-ray energy of 4 to 12 keV and a maximum optical path length of 2 mm or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If heavy metal contrast agents are used to enhance X-ray absorption contrast, then contrast is improved, but penetration into biological samples becomes insufficient and artifacts increase
Solution Approach 1:
The patent changes the physical parameters of the contrast agent by using wax with specific density (0.95 g/cm³ or less) and melting point (40-80°C) characteristics. This parameter optimization allows the contrast agent to penetrate biological samples effectively while providing sufficient X-ray contrast at low energies (4-12 keV), resolving the contradiction between contrast enhancement and penetration capability.
Solution Approach 2:
The patent utilizes phase transition of the wax contrast agent - it is introduced in liquid form for penetration, then solidifies within the biological sample to provide stable contrast. The controlled solidification at specific temperatures ensures the contrast agent remains in the desired phase during penetration and imaging, improving both penetration and contrast reliability.
2Measurement precision
If heavy metal contrast agents are used to improve contrast, then visualization capability is enhanced, but the biological sample integrity is compromised and artifacts are generated
Solution Approach 1:
The patent employs wax as a temporary, biocompatible contrast agent that can be removed or degraded without harming the biological sample. Unlike heavy metals, the wax does not cause radiation damage or chemical toxicity, maintaining sample integrity while providing sufficient contrast for visualization purposes.
Solution Approach 2:
The patent converts the low X-ray absorption property of light elements (which normally produces poor contrast) into a benefit by using wax with optimized density and atomic number. The wax provides just enough absorption to create visible contrast at low energies while avoiding the harmful effects of heavy metals, turning a limitation into an advantage for sample preservation.
3Reliability
If X-ray energy is increased to improve penetration through biological samples, then penetration is enhanced, but contrast from light elements becomes insufficient
Solution Approach 1:
The patent changes the X-ray energy parameter to a specific low-energy range (4-12 keV) that optimizes both penetration and contrast. At these energies, the wax contrast agent provides sufficient absorption differential while still allowing adequate penetration through the biological sample, resolving the contradiction between penetration and contrast.
Solution Approach 2:
The patent introduces wax as an intermediary contrast agent that mediates between the X-ray source and the biological sample. The wax absorbs X-rays to a degree that creates visible contrast while allowing enough radiation to pass through for image acquisition, serving as an optimal intermediary that balances penetration and contrast requirements.
4Area of stationary object
If the biological sample size is increased to improve observation scope, then observation capability is enhanced, but X-ray absorption becomes too weak to achieve sufficient contrast
Solution Approach 1:
The patent changes the contrast agent parameters (wax with density ≤0.95 g/cm³ and melting point 40-80°C) to optimize the contrast-to-noise ratio. This allows larger biological samples to be imaged with sufficient contrast, as the optimized wax provides enhanced absorption characteristics that maintain visibility even in larger specimens.
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 the acquisition of high-quality, fine-resolution X-ray CT images with a voxel size of 5 μm or less, reducing artifacts and enhancing image clarity for biological samples.
Implementation Method 1
a step of penetrating a contrast agent into the biological sample and solidifying the contrast agent to provide a contrast image of the biological sample
Implementation Method 2
a step of melting and resolidifying the solidified contrast agent
Implementation Method 3
detecting the intensity of transmitted X rays... combining images indicating a spatial distribution of an X-ray absorption coefficient
Data Source
AI summary
Obtaining an X-ray CT image of a biological sample includes a step of penetrating a contrast agent into the biological sample and solidifying the contrast agent to provide a contrast image of the biological sample, the contrast agent comprising wax and having a density of 0.95 g/cm3 or less in its solidified state after penetration into the biological sample, and having a melting point of 40° C. to 80° C., a step of melting and resolidifying the solidified contrast agent, and a step of acquiring an X-ray CT image by irradiating the resolidified biological sample with an X ray having an energy of 4 to 12 keV, the shape of the biological sample being a shape with which a maximum optical path length of the X ray in the biological sample in the step of acquiring an X-ray CT image is 2 mm or less.