Hybrid MPI-CT Scanner Simultaneous Imaging
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Solution Overview
Problem
Existing hybrid scanners, such as MRI/PET and PET/CT, face challenges with high costs, insufficient temporal and spatial resolution of functional information, and the use of radioactive contrast media, which poses radiation exposure risks to patients and staff.
Innovation Solution
A hybrid scanner combines Magnetic Particle Imaging (MPI) and X-ray Computed Tomography (CT) to generate tomographic images, using a field-free point or line trajectory to determine magnetizable particle concentrations, allowing for simultaneous recording of X-ray images and magnetic field measurements to correct for disturbances and improve image reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hybrid scanners combine multiple imaging modalities (MRI/PET, PET/CT, SPECT/CT), then diagnostic capability is improved, but costs increase and radiation exposure risks arise
Solution Approach 1:
The patent combines MPI and CT into a hybrid scanner that acquires both functional particle concentration data and morphological X-ray attenuation data simultaneously. This merging provides comprehensive diagnostic capability (tissue functionality from MPI + tissue morphology from CT) while avoiding the radiation exposure associated with PET and SPECT modalities, as MPI uses non-radioactive magnetizable particles
Solution Approach 2:
The hybrid scanner performs multiple imaging functions within a single device: CT provides morphological imaging, MPI provides functional imaging of particle concentrations, and both datasets are integrated for comprehensive tissue characterization. This multi-functionality achieves the versatility of multiple separate scanners while eliminating the need for radioactive contrast agents in the functional imaging component
2Measurement precision
If MPI uses a single field-free point (FFP) trajectory, then spatial resolution is improved, but data acquisition time increases
Solution Approach 1:
The patent transitions from moving a single FFP along a one-dimensional or two-dimensional trajectory to generating and moving a field-free line (FFL) through three-dimensional space. This dimensional expansion allows simultaneous sampling of multiple spatial locations along the line, effectively reducing data acquisition time by an order of magnitude while maintaining spatial resolution through the extended sampling coverage
Solution Approach 2:
By using a continuous field-free line instead of discrete point measurements, the system maintains continuous useful action during data acquisition. The FFL traverses through the object continuously, collecting data along its entire path, which maximizes the information gained per unit time and significantly reduces total acquisition time compared to point-by-point FFP sampling
3Productivity
If MPI and CT are performed simultaneously in a hybrid scanner, then productivity is improved, but magnetic field disturbances from CT affect MPI measurement precision
Solution Approach 1:
The patent implements a feedback mechanism where the actual magnetic field distribution is continuously measured during simultaneous CT-MPI operation. These measured field values are fed back into the image reconstruction algorithm to correct for deviations from the ideal field distribution, thereby maintaining MPI measurement precision despite the presence of CT-generated magnetic field disturbances
Solution Approach 2:
The patent introduces magnetic field sensors as intermediary devices that measure the actual magnetic field conditions during simultaneous operation. These sensors act as mediators between the disturbed magnetic field environment and the MPI measurement system, providing real-time data that enables correction of field distortions and maintains measurement accuracy
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 combination enables more efficient and accurate image reconstruction, reducing data acquisition times and avoiding the use of radioactive materials, thus enhancing patient and staff safety while improving diagnostic capabilities.
Implementation Method 1
the magnetization of the particles depending non-linearly on the magnetic field strength
Implementation Method 2
the selection magnetic field increases rapidly in all directions, causing magnetizable nanoparticles to reach magnetic saturation
Implementation Method 3
X-ray CT allows the determination of location-dependent X-ray attenuation coefficients within the patient's body
Data Source
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AI summary
A medical imaging technique for patients combines an X-ray-based computed tomography (CT) scanner and a magnetic particle imaging (MPI) system in a hybrid scanner. MPI and X-ray CT measurements are acquired simultaneously and in relation to each other, and then jointly analyzed for image reconstruction. The technique is also designed to minimize artifacts resulting from the combination of the measurement systems.