SPECT Spatial Resolution Correction via 3D Frequency Space
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Solution Overview
Problem
In Single Photon Emission CT (SPECT) apparatuses, the spatial resolution of gamma ray detection is compromised due to varying distances between radiation sources and detectors, making it difficult to effectively correct spatial resolution in two-dimensional projection distributions before reconfiguration.
Innovation Solution
A SPECT apparatus with a two-dimensional detector and a correction processing unit that corrects plural two-dimensional projection distributions in a three-dimensional frequency space using plural correction functions corresponding to different distances, and a reconfiguring unit that reconfigures a three-dimensional RI distribution from the corrected projections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If filter processing is applied to two-dimensional projection distribution data before reconfiguration, then noise reduction and spatial resolution correction are improved, but the distances between radiation sources and detector cannot be separated, making effective correction impossible
Solution Approach 1:
The patent transforms the two-dimensional projection distribution data into a three-dimensional frequency space (sinogram space) where the distance information between radiation sources and detector becomes separable and accessible. This dimensional transformation enables the application of distance-specific correction functions that were impossible in the original 2D space.
2Measurement precision
If correction functions are applied in three-dimensional frequency space, then spatial resolution correction for different distances is improved, but data transformation and processing complexity increase
Solution Approach 1:
The patent replaces the conventional mechanical approach of physical filtering with mathematical transformation in frequency space. By using Fourier transformation to convert spatial domain data to frequency domain, the system achieves more precise correction without physical constraints.
3Measurement precision
If incidence width of gamma rays is reduced to improve spatial resolution, then detection precision improves, but sensitivity and detection efficiency decrease
Solution Approach 1:
The patent changes the parameter space from physical incidence width control to frequency domain correction parameters. By transforming data to three-dimensional frequency space, the system can apply correction functions that adjust spatial resolution without physically limiting gamma ray incidence, thus maintaining detection efficiency.
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 allows for the effective separation and correction of spatial resolution issues by transforming data into a three-dimensional frequency space, enabling improved spatial resolution and sensitivity adjustments based on radiation source-detector distances.
Implementation Method 1
a two-dimensional detector 2 that detects radiations from RIs in a patient via a collimator 3
Data Source
AI summary
A SPECT apparatus has a two-dimensional detector that detects radiations from RIs in a patient via a collimator. A correction processing unit corrects plural two-dimensional projection distributions with different projection angles, which are detected by the detector, on a three-dimensional frequency space according to plural correction functions corresponding to plural distances, respectively. Consequently, a fall in spatial resolution having dependency on distances between the respective RIs and the detector is reduced. A reconfiguring unit reconfigures a three-dimensional RI distribution from the plural two-dimensional projection distributions corrected.