Time-of-flight X-ray Imaging Reducing Radiation Exposure
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Solution Overview
Problem
Traditional x-ray imaging systems face challenges in reducing radiation exposure while maintaining image quality, as they rely on attenuation-based methods that require high doses of radiation, posing risks to patients and being inefficient for large-scale human imaging.
Innovation Solution
The system employs time-of-flight x-ray imaging by measuring the refractive index of x-rays as they pass through the body, using a clock and detector system to calculate the time of flight and reconstruct images, significantly reducing radiation exposure by utilizing the greater contrast provided by refractive index information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional attenuation-based x-ray imaging is used, then image quality can be achieved, but radiation exposure to patients increases
Solution Approach 1:
The patent changes the imaging parameter from attenuation-based detection to time-of-flight detection. By measuring the time delay of x-ray photons as they pass through different tissues, the system obtains refractive index information that provides superior contrast resolution. This parameter change allows achieving the same or better image quality with significantly reduced radiation exposure, as the time-of-flight measurement is more sensitive to tissue differences than attenuation methods.
2Measurement precision
If higher radiation doses are used, then contrast resolution and spatial resolution increase, but tissue damage risk increases
Solution Approach 1:
The patent replaces the traditional mechanical attenuation-based detection system with a time-of-flight detection system. Instead of measuring the reduction in photon count (attenuation), the system measures the time delay of photons passing through tissues. This substitution enables achieving high contrast resolution at lower radiation doses because time-of-flight measurements provide more information per photon, reducing the need for high photon flux that would increase tissue damage risk.
3Quantity of substance
If attenuation-based methods are used, then imaging can be performed, but information efficiency decreases requiring higher doses
Solution Approach 1:
The patent changes the detection parameter from photon count (attenuation) to photon arrival time (time-of-flight). This parameter change dramatically improves information efficiency because the time delay provides direct information about the refractive index and path length through different tissues. Each photon carries more diagnostic information in the time-of-flight measurement compared to attenuation methods, reducing the total photon count needed and thus lowering radiation exposure requirements.
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 reduces x-ray exposure by orders of magnitude, enabling clinically useful images with lower doses, suitable for human subjects, and allowing for imaging of asymptomatic patients and vulnerable populations without the negative effects of cumulative radiation.
Implementation Method 1
measuring the refractive index (i.e., ratio of x-ray velocity through matter as compared to velocity through a vacuum) of x-rays through a body
Implementation Method 2
measuring the refractive index (i.e., ratio of x-ray velocity through matter as compared to velocity through a vacuum) of x-rays through a body
Implementation Method 3
A detector system is included that detects the photons
Data Source
AI summary
A system and method for imaging a subject includes a clock that generates a clock signal and a radiation source that directs photons through the subject in response to the clock signal. A detector system is included that detects the photons and a memory module records a time of detection of the photons by the detector system with respect to the clock signal. The system includes a processor that calculates a time of flight (TOF) of the photons from the radiation source to the detector system and compares the TOF to a reference TOF to determine a delay in the TOF attributable to the photons passing trough the subject.