Angled PCCT Detector Array Layout for Reduced Internal Scatter
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Solution Overview
Problem
Photon counting computed tomography (PCCT) systems suffer from internal scatter crosstalk between sensor subunits, leading to stochastic noise and reduced image detail, which conventional anti-scatter grids fail to address effectively.
Innovation Solution
The system employs a gantry-configured detector array with PCCT detector units arranged at angles relative to the rotation axis, incorporating anti-scatter grids and X-ray absorbing materials like tungsten fins, along with strategic pixel orientations and image processing techniques to correct for internal scatter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an anti-scatter grid is positioned between sensors to absorb scattered X-ray photons, then inter-sensor scatter is reduced, but internal scatter between sensor subunits within a sensor remains unaddressed and causes stochastic noise
Solution Approach 1:
The sensor is divided into multiple sensor subunits (pixels) arranged in a grid pattern. By segmenting the sensor into discrete subunits with spacing between them, the patent enables selective absorption of scattered photons that travel between subunits while allowing primary photons to reach their intended targets. The anti-scatter grid is positioned to absorb scattered photons in the spaces between subunits without blocking primary photons.
Solution Approach 2:
An anti-scatter grid is introduced as an intermediary component between the X-ray source and the sensor subunits. This grid acts as a mediator that selectively absorbs scattered X-ray photons while allowing primary photons to pass through to the sensor. The grid is positioned at a specific distance from the sensor to optimize its ability to intercept scattered photons without blocking the primary beam.
2Area of stationary object
If sensor subunits are positioned close together to increase detection coverage, then imaging area is increased, but internal scatter between adjacent subunits increases causing image degradation
Solution Approach 1:
The sensor is segmented into multiple discrete subunits with controlled spacing. This segmentation allows the sensor to cover a large imaging area while maintaining separation between subunits to reduce internal scatter. The anti-scatter grid further enhances this segmentation effect by absorbing photons that scatter between adjacent subunits.
Solution Approach 2:
Different regions of the sensor have different properties: the active sensing areas (subunits) are positioned to maximize coverage, while the spaces between subunits are designed to allow scattered photon absorption. The anti-scatter grid is strategically positioned to provide local scatter absorption in the inter-subunit regions without affecting the primary detection function of the subunits.
3Object-affected harmful factors
If the anti-scatter grid is positioned close to the sensor to maximize scatter absorption, then scatter reduction is improved, but the grid blocks more primary photons reducing detection efficiency
Solution Approach 1:
The anti-scatter grid is positioned at an optimal distance from the sensor that allows it to intercept scattered photons before they reach the sensor subunits, while not being so close as to block primary photons. This preliminary positioning of the grid creates a scatter-free zone in front of the sensor without compromising primary photon detection.
Solution Approach 2:
The problem is solved by transitioning from a two-dimensional sensor surface to a three-dimensional arrangement that includes the anti-scatter grid positioned in space in front of the sensor. This additional dimension allows the grid to absorb scattered photons from multiple angles without blocking the primary beam path to the sensor subunits.
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 enhances image resolution and reduces spectral corruption by effectively mitigating internal scatter, resulting in higher-quality PCCT images.
Implementation Method 1
An anti-scattering grid may be positioned between sensors of the PCCT detecting unit to absorb the X-ray photons scattered between sensors
Implementation Method 2
The active material of the sensor is a semiconductor (e.g., silicon) which directly converts energy of the incoming X-ray photons into electrical signals
Data Source
AI summary
Systems are provided for a computed tomography system, comprising a gantry configured to rotate around an axis of rotation and a detector array comprised of a plurality of photon-counting computed tomography (PCCT) detector units configured to be rotated around the axis of rotation by the gantry, wherein a stacking axis of least one of the plurality of PCCT detector arrays is positioned at an angle with respect to the axis of rotation.