Thick Septa Collimator Shadow Reduction via Synthetic Collywobbling
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Solution Overview
Problem
Thick septa collimators in X- and gamma-ray imaging produce septal shadows that distort images and prevent accurate determination of hole orientation angles, leading to inaccurate vector maps and degraded tomographic image quality.
Innovation Solution
A method involving synthetic collywobbling, where a line radiation source is positioned relative to a thick septa collimator, and multiple images are taken at different locations, relocated to a common position, and summed to reduce septal shadow effects, allowing for accurate calculation of hole orientation angles and improved image reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thick septa collimators are used for high energy imaging, then photon absorption capability is improved, but septal shadows are produced which distort images
Solution Approach 1:
The collimator is dynamically moved relative to the radiation source during image acquisition. By translating the collimator in multiple positions and summing the resulting images, the static septal shadows are transformed into a dynamic averaging process that reduces shadow artifacts while maintaining the thick septa structure for high energy photon absorption
Solution Approach 2:
The collimator undergoes periodic translation through multiple positions during the imaging process. This periodic movement allows the system to sample the radiation pattern at different locations, and when images are summed, the periodic displacement averages out the septal shadow artifacts while preserving the photon absorption capability of thick septa
2Reliability
If thick septa collimators are used, then photon absorption capability is improved, but accurate determination of hole orientation angles becomes difficult
Solution Approach 1:
By moving the collimator to multiple positions and summing the images, the method creates a dynamic measurement process that averages out the distortion caused by thick septa. This allows accurate determination of hole orientation angles even when using thick septa collimators for high energy imaging
Solution Approach 2:
The method creates multiple copies of the radiation pattern at different collimator positions. By summing these copies, an averaged image is produced that represents the true radiation distribution without the distorting effects of septal shadows, enabling accurate measurement of hole orientation angles
3Reliability
If septal thickness is increased to absorb penetrating photons, then imaging reliability is improved, but image quality is degraded due to shadow artifacts
Solution Approach 1:
The collimator is translated through multiple positions during image acquisition, transforming the static shadow artifacts into a dynamic averaging process. When images from different positions are summed, the septal shadow artifacts are reduced while maintaining the thick septa structure necessary for absorbing penetrating photons at high energies
Solution Approach 2:
The method converts the harmful effect of thick septa (causing shadow artifacts) into a beneficial measurement process. By deliberately moving the collimator through multiple positions and summing the images, the process uses the thick septa structure to define measurement locations while the movement averages out the shadow artifacts, improving both reliability and image quality
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 effectively minimizes septal pattern artifacts, enabling accurate determination of collimator hole directions and enhancing the quality and accuracy of tomographic images by averaging out septal shadows, applicable to both parallel and focusing collimators.
Implementation Method 1
Radiopharmaceuticals are introduced into the body, either by injection or ingestion, and are attracted to specific organs, bones or tissues of interest. Such radiopharmaceuticals produce gamma photon emissions that emanate from the body.
Implementation Method 2
a collimator placed between the source and a scintillation crystal or solid state detector, to allow only gamma rays aligned with the holes of the collimator to pass through to the detector
Implementation Method 3
The walls surrounding and defining the collimator holes (septa) are designed to be sufficiently thick to absorb photons not traveling in the desired direction
Implementation Method 4
One or more detectors are used to detect the emitted gamma photons, and the information collected from the detector(s) is processed to calculate the position of origin of the emitted photon from the source
Data Source
AI summary
Disclosed herein is a method for removing septal shadows from thick septa collimator images, comprising disposing a line radiation source in a first orientation with respect to an imaging detector; disposing a thick septa collimator between the line radiation source and the imaging detector; where the collimator and the detector move in unison with one another; obtaining a plurality of a line images, where each line image is taken at a different location of the line radiation source with respect to the thick septa collimator; wherein each different location of the line radiation source is along a first linear direction; and relocating the plurality of the line images so obtained to a common location; and summing the images to reduce the septal shadow effects.