PET Data Processing Using Azimuthal Scattering Angles
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Solution Overview
Problem
Current PET imaging systems face challenges in accurately distinguishing scattered photons from unscattered ones in real-time, leading to noise in imaging data due to scattering events and random coincidences, which complicates image reconstruction and requires significant computational resources and additional scans.
Innovation Solution
The method employs azimuthal scattering angles to differentiate between entangled and non-entangled photon pairs, using the polarisation properties of entangled photons to reduce the impact of scattering events by processing PET data based on first and second azimuthal scattering angles, allowing for rapid image reconstruction with improved signal-to-noise ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a threshold close to 511 keV is used to remove scattering events, then scattering events are removed from the data, but true events are also removed
Solution Approach 1:
The patent segments the PET data into multiple categories based on energy deposition patterns: single-crystal events (511 keV), Compton scattering events (partial energy deposition), and paired Compton events. This segmentation allows differential processing of each event type, enabling scatter correction without discarding true events that fall into specific energy categories.
Solution Approach 2:
The patent applies different processing quality levels to different regions of the data. Events with specific energy deposition characteristics (indicating scattering) are processed differently from events with full energy deposition. This local differentiation enables selective correction of scattering artifacts while preserving true anatomical signals.
2Reliability
If Monte Carlo simulation is used to correct for scattering events, then scattering correction is achieved, but significant computational resources and time are required
Solution Approach 1:
The patent performs preliminary classification of events into distinct categories (single-crystal, Compton, paired Compton) based on their energy deposition characteristics during data acquisition. This preliminary sorting enables rapid processing by treating each event category according to its specific properties, avoiding the need for time-consuming Monte Carlo simulations for each individual event.
Solution Approach 2:
Instead of performing complex Monte Carlo simulations to model scattering, the patent uses simplified analytical models and lookup tables that replicate scattering correction effects. These pre-computed models provide equivalent scatter correction with minimal computational overhead, effectively copying the results of complex simulations without the computational cost.
3Reliability
If additional scans with X-ray source are performed to map source distribution, then scatter modeling is improved, but additional dose is added to the scan
Solution Approach 1:
The patent enables the PET scanner to self-characterize the patient's anatomy and scattering properties using the PET data itself and the known physics of photon interactions. By analyzing energy deposition patterns and using the patient's own tissue density information from the PET scan, the system performs scatter correction without requiring external X-ray imaging, thereby avoiding additional radiation exposure.
4Area of stationary object
If all events with two energy depositions of around 511 keV are used for image reconstruction, then image coverage is maximized, but noise from scattering events increases
Solution Approach 1:
The patent segments events into distinct physical categories based on their energy deposition signatures. By separating single-crystal 511 keV events from Compton scattering events and paired Compton events, the system can selectively include only the appropriate event types in the image reconstruction, maintaining comprehensive coverage while filtering out noise-generating scattering events.
Solution Approach 2:
The patent changes the selection criteria for events based on energy deposition parameters. Instead of using a fixed threshold, the system dynamically adjusts event inclusion criteria based on the measured energy values, crystal interaction patterns, and azimuthal scattering angles. This parameter-based filtering allows the system to adaptively select high-quality events for reconstruction while maintaining comprehensive imaging coverage.
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 enables real-time processing of PET data to reduce the effect of scattering events, resulting in improved image quality with reduced noise and faster reconstruction times, without the need for additional scans or complex computational models.
Implementation Method 1
using the polarisation properties of entangled photons to reduce the impact of scattering events
Implementation Method 2
a photon undergoes Compton scattering within a first detector element, depositing part of its energy in that first detector element
Data Source
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AI summary
A method of, and apparatus for, processing positron emission tomography data A positron emission tomography (PET) data processing method comprises obtaining PET data from a PET detector, wherein the PET detector comprises an array of scintillator elements, and wherein the PET data is representative of a PET measurement of at least part of a subject. The method comprises identifying in the PET data a plurality of paired events, wherein each paired event comprises a first photon event in a first region of the PET detector and a second photon event in a second region of the PET detector. The first photon event comprises an energy deposition in a first scintillator element of the array due to a scattering of a first photon at a first azimuthal scattering angle and an associated energy deposition by the scattered first photon in a second scintillator element of the array. The second photon event comprises an energy deposition in a third scintillator element of the array due to a scattering of a second photon at a second azimuthal scattering angle and an associated energy deposition by the scattered second photon in a fourth scintillator element of the array. The method further comprises processing the PET data in dependence on the first and second azimuthal scattering angles for the paired events.