Primary Beam Modulation for Single-Scan Dual-Energy CT
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current dual-energy computed tomography (DECT) techniques require impractical hardware or are time-consuming, often resulting in artifacts due to patient motion, and struggle to distinguish between materials with similar attenuation coefficients using a single photon spectrum.
Innovation Solution
A method and system for DECT that uses a CT scanner with an x-ray source and detector positioned on either side of an object, employing a primary modulator with a spatially-varying attenuation pattern to modulate x-ray energy, allowing for simultaneous acquisition of high and low energy projection data in a single scan, which can be reconstructed iteratively without requiring complex or costly hardware upgrades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sequential scanning with different energies is used, then dual-energy projection data can be obtained, but imaging time increases and motion artifacts occur
Solution Approach 1:
The patent applies periodic action by using a dynamically switching attenuator that alternates between different attenuation states during a single scan. The attenuator switches between high-attenuation and low-attenuation configurations at periodic intervals, enabling the acquisition of both high-energy and low-energy projection data simultaneously within one rotational cycle, thereby eliminating the need for sequential scanning and reducing imaging time while preventing motion artifacts.
2Measurement precision
If specialized hardware is used for DECT, then dual-energy data can be acquired simultaneously, but system complexity and cost increase
Solution Approach 1:
The patent applies universality by designing a multi-functional attenuator that can dynamically assume different attenuation configurations to serve multiple purposes. The same attenuator structure is used to generate both high-energy and low-energy beam configurations, replacing the need for separate dedicated hardware systems. This multi-functional approach enables simultaneous dual-energy data acquisition using a single integrated component rather than multiple specialized devices.
Solution Approach 2:
The patent applies self-service by utilizing the existing CT scanner hardware components (x-ray source, detector, rotational mechanism) to perform dual-energy imaging. The system uses its own built-in attenuator, which can be dynamically reconfigured, rather than requiring external specialized hardware. The existing scanner infrastructure serves the additional function of dual-energy imaging through software-controlled attenuator modulation.
3Device complexity
If a single photon spectrum is used, then the scanning system is simple, but materials with similar attenuation coefficients cannot be distinguished
Solution Approach 1:
The patent applies parameter changes by dynamically modifying the effective x-ray beam energy parameters through attenuator configuration changes. By switching the attenuator between different attenuation states, the system varies the average photon energy of the x-ray beam, creating distinct high-energy and low-energy spectral configurations from a single x-ray source. This enables material differentiation based on energy-dependent attenuation differences while maintaining system simplicity.
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
Enables efficient single-scan DECT imaging on conventional CT scanners, achieving sufficient spectral separation and material differentiation without the need for redundant projection data or complex hardware, while reducing artifacts and improving image resolution through iterative reconstruction and decomposition algorithms.
Implementation Method 1
x-ray attenuation measurements are acquired by passing photon beams through an object at many different projection angles
Implementation Method 2
A primary modulator, which is an attenuation (i.e., filter) sheet with a spatially-varying pattern of attenuation (i.e., filtration), is positioned between the x-ray source and the object
Data Source
AI summary
Disclosed herein is a system and method, which utilize primary beam modulation to enable single-scan dual-energy CT (DECT) on a conventional CT scanner. An attenuation sheet with a spatially-varying pattern is placed between the x-ray source and the imaged object. During the CT scan, the modulator selectively hardens the x-ray beam at specific detector locations. Thus, this method simultaneously acquires high and low energy data at each projection angle. High and low energy CT images can then reconstructed from the projections via an iterative CT reconstruction algorithm, which accounts for the spatial modulation of the projected x-rays.