X-ray Fluorescence Detector Array with Aperture Slats for Background Noise Reduction
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Solution Overview
Problem
Conventional X-ray fluorescence imaging techniques face challenges with low sensitivity, high radiation doses, and limited spatial resolution, making them unsuitable for clinical applications, especially for large objects like humans, due to background interference and inefficiencies in detecting fluorescent markers.
Innovation Solution
The method involves generating a narrow X-ray beam parallel to a projection direction, scanning the object in multiple positions, and using a detector array with spectrally selective elements and aperture slats to reduce background noise and enhance signal detection by identifying significant detector elements that provide increased statistical significance for X-ray fluorescence signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional RFB techniques are used for X-ray fluorescence imaging, then the method can detect fluorescent target particles, but the background noise increases significantly with object size, reducing sensitivity for large objects like humans
Solution Approach 1:
The detector is divided into multiple detector elements arranged in different spatial directions. By segmenting the detection process into direction-specific measurements, the system can identify and select only those detector elements that receive fluorescence photons from the irradiated volume, while excluding elements that detect scattered radiation from outside the volume. This segmentation enables background reduction by a factor of approximately 600 to 1000.
Solution Approach 2:
Different detector elements are assigned different functions based on their spatial orientation. Elements positioned to detect photons from the irradiated volume are used for signal detection, while elements positioned to detect scattered radiation are excluded or used for background characterization. This local differentiation of detector element quality and function enables selective background suppression.
2Power
If conventional X-ray tubes are used as X-ray sources, then the device can be compact, but the radiation has too large divergence and too low intensity, resulting in insufficient signal for clinical applications
Solution Approach 1:
A laser-based Thomson source is introduced as an intermediary between conventional X-ray tubes and synchrotron facilities. This source uses a laser to excite relativistic electrons, producing highly intense, low-divergence X-ray beams with controllable energy. The Thomson source acts as a bridge, providing clinical-grade beam quality in a more compact and accessible configuration than synchrotrons while avoiding the limitations of conventional tubes.
3Measurement precision
If PET is used for molecular imaging, then radiopharmaceuticals can be detected in the body, but the spatial resolution is limited to 4 to 6 mm and the temporal resolution is insufficient for pharmacokinetic studies
Solution Approach 1:
The invention changes the detection parameter from radioactive decay detection (PET) to X-ray fluorescence detection. This parameter change enables millimeter-scale spatial resolution (improving upon PET's 4-6 mm limitation) while allowing repeated measurements over time without the short lifetime constraints of radiopharmaceuticals. The X-ray fluorescence method provides both high spatial and temporal resolution suitable for pharmacokinetic studies.
4Object-affected harmful factors
If collimator geometries are used to reduce RFB background, then background can be reduced, but the field of view of detector elements is limited, resulting in signal loss that requires higher irradiation dose
Solution Approach 1:
Instead of using collimators that limit the field of view in the horizontal plane, the invention uses the spatial dimension of detector element orientation. By arranging detector elements in different spatial directions and selecting based on their orientation relative to the irradiated volume, the system achieves background reduction without limiting the field of view. This dimensional approach to background rejection avoids signal loss.
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 significantly increases sensitivity and reduces background noise, allowing for the detection of minimal amounts of functionalized gold nanoparticles in humans with an acceptable radiation dose, enabling clinical X-ray fluorescence imaging and early tumor diagnosis.
Implementation Method 1
In XRF, the biomarkers are bound to gold nanoparticles, for example, which are stimulated to emit X-ray fluorescence by a scanning X-ray beam
Implementation Method 2
The RFB background increases with the size of the object, as the probability that the incident X-ray photons will experience multiple Compton scattering increases
Data Source
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AI summary
A method for an x-ray fluorescence measurement, in which the presence of fluorescing target particles is captured in an object (1) to be examined and target particles that are present are localized in the object (1), comprises the steps of (a) producing an x-ray beam (2) by means of a source device (10), wherein the x-ray beam (2) extends through the object (1) in an x-ray beam direction parallel to a first projection direction, (b) irradiating the object (1) with the x-ray beam (2) at a multiplicity of scan positions in a first projection plane, wherein the scan positions are set by a scanning device (20), by means of which the source device and the object (1) are moved relative to one another, (c) detecting x-ray radiation, emitted from the object (1) in a plurality of spatial directions, at each scan position using a detector array device (30), which is securely connected to the source device (10), wherein the detector array device (30) comprises a multiplicity of spectrally selective detector elements (31), which are arranged to detect the x-ray radiation in the multiplicity of spatial directions, and a plurality of stop lamellas (32), which extend in radial directions relative to the x-ray beam direction, which shield the detector elements (31) from x-ray radiation scattered in the object (1) and which are arranged in such a way that the detector elements (31) are able to detect x-ray radiation from all locations within the volume of the x-ray beam in the object (1), and (d) processing detector signals of the detector elements in order to capture x-ray fluorescence of target particles in the detected x-ray radiation and in order to localize the target particles in the object (1) if the x-ray fluorescence is captured, wherein a subset of significant detector elements (31) is sought after for each of a multiplicity of predetermined scan positions, the detector signals of said detector elements facilitating the capture of the x-ray fluorescence of the target particles with a statistical significance that is elevated in comparison with the remaining detector elements (31), and, if significant detector elements (31) are found at at least one scan position, the presence of target particles is captured and this scan position is established as a target scan position, at which the target particles are localized in the first projection plane, or, if significant detector elements (31) are found at no scan position, the presence of no target particles is captured. An x-ray fluorescence measuring apparatus is also described.