X-ray Fluorescence Computed Tomography Using Liquid-Jet-Anode Source
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Solution Overview
Problem
Current x-ray fluorescence computed tomography (XFCT) systems face limitations in resolution and contrast due to noise and background radiation, primarily caused by Compton scattering and the need for thick filters, which increase scan time and require high-power x-ray tubes.
Innovation Solution
Employing a line emitting, quasi-monochromatic liquid-jet-anode x-ray source combined with energy-selective beam forming optics and photon-counting detection to reduce background radiation and enhance signal-to-noise ratio, using nanoparticles with matched core materials to achieve higher spatial resolution and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thick filters are used to reduce background radiation and improve signal-to-background ratio, then the signal-to-background ratio is improved, but scan time increases at a much higher rate
Solution Approach 1:
The patent replaces mechanical filters (thick physical filters) with a computational approach using spline-function data fitting and piecewise cubic Hermitian polynomial interpolation to model and subtract background radiation. This substitution eliminates the need for thick filters that would otherwise be required to achieve adequate background suppression, thereby avoiding the exponential increase in scan time that would result from using such filters.
Solution Approach 2:
The patent changes the approach from physical parameter modification (filter thickness) to mathematical parameter processing (data fitting coefficients and polynomial parameters). By using mathematical models to represent and remove background, the system achieves background suppression without the time penalty associated with increasing physical filter thickness.
2Measurement precision
If thicker filters are used to increase signal-to-dose ratio, then the signal-to-dose ratio increases exponentially, but higher power x-ray tubes are required to maintain adequate signal levels
Solution Approach 1:
The patent replaces the mechanical solution of using thicker filters (which would require higher power tubes) with a computational background subtraction method. This allows the system to achieve high signal-to-dose ratios using standard-power x-ray tubes by mathematically removing the background component rather than physically blocking it with filters.
Solution Approach 2:
The patent introduces mathematical models (spline functions and polynomial interpolations) as intermediaries between the raw signal and the final processed signal. These mathematical intermediaries enable the separation of signal from background without requiring physical intermediaries (thick filters) that would necessitate higher x-ray tube power.
3Illumination intensity
If polychromatic x-ray spectrum is used for excitation, then fluorescence signal is generated, but considerable background signal from Compton scattering and nanoparticle excitation must be filtered out
Solution Approach 1:
The patent extracts the background signal component from the total measured signal using mathematical modeling techniques. By fitting spline functions and piecewise cubic Hermitian polynomials to the background regions, the system separates and removes the harmful background components (Compton scattering and nanoparticle excitation) from the useful fluorescence signal.
Solution Approach 2:
The patent replaces physical filtering methods with computational signal processing. Instead of using physical filters to remove background radiation, the system uses mathematical algorithms to identify, model, and subtract background components from the measured spectrum, thereby preserving the fluorescence signal while eliminating background interference.
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 results in a tenfold improvement in observable spatial resolution and higher sensitivity, with significantly reduced exposure times and doses, enabling sub-millimeter resolution imaging.
Implementation Method 1
A line emitting, liquid-jet-anode x-ray source provided high brightness x-ray radiation
Implementation Method 2
shaping the x-ray radiation into a pencil beam to induce x-ray fluorescence from nanoparticles
Implementation Method 3
x-ray fluorescence computed tomography (XFCT) for molecular imaging of various cells loaded with metallic nanoparticles
Implementation Method 4
embodiments of the present invention make use of x-ray optics in the form of multilayer mirrors, or possibly Fresnel zone plates, to shape the x-rays into a suitable pencil beam
Implementation Method 5
Excitation of the nanoparticles themselves as well as Compton scattering produce a considerable background signal
Implementation Method 6
combining a line emitting, high-brightness liquid-jet-anode x-ray source, energy-selective optics, photon-counting and energy-dispersive detection
Implementation Method 7
photon-counting and energy-dispersive detection and matched nanoparticle core materials
Data Source
AI summary
The disclosure provides improvements of resolution and contrast in the field of x-ray imaging by using a line emitting, quasi-monochromatic x-ray source for x-ray fluorescence computed tomography. A particular type of x-ray source suitable for this is a line emitting liquid-jet-anode x-ray source. X-ray fluorescence is obtained using nanoparticles, preferably coated nanoparticles with a metallic core. The x-ray radiation from the x-ray source is shaped and filtered using energy dispersive optics before being delivered to the nanoparticles.