Curved CT Image Sensor for Artifact Reduction
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Solution Overview
Problem
Conventional computed tomography (CT) systems are large, heavy, and expensive, making them unsuitable for smaller healthcare facilities, and face challenges with image quality due to sensitivity variations, radiation damage, and maintenance complexities, particularly in reducing X-ray dose and environmental influences.
Innovation Solution
The CT system incorporates image sensors with a concave semiconductor substrate at an angle of 45 to 90 degrees to the object, integrated circuits on a single die, and a stacked configuration with a metal optical shield and scintillator film, enabling reduced size, weight, and improved image quality while minimizing environmental influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional area image sensors with flat pixel arrays are used, then manufacturing is simplified, but image quality degrades due to artifacts from X-ray attenuation at different incident angles
Solution Approach 1:
The patent applies curvature by forming the semiconductor substrate surface as a curved surface (specifically a spherical or cylindrical surface) that faces the fan beam X-ray source. This curved surface configuration allows X-rays incident at different angles to be properly detected, eliminating the artifacts that occur with flat surfaces while maintaining manufacturing feasibility through standard semiconductor processing techniques adapted to curved geometries.
2Manufacturing precision
If the number of pixels or slices is increased to improve image quality, then spatial resolution improves, but the cone angle of X-ray increases causing artifacts and degrading image quality
Solution Approach 1:
The curved surface configuration of the semiconductor substrate is specifically designed to match the fan beam geometry. By increasing the number of pixels along this curved surface, the system can capture a wider angular range of X-rays without increasing the cone angle artifacts, because each pixel is positioned at the optimal angle relative to the X-ray source according to the curved geometry.
Solution Approach 2:
The patent transitions from a two-dimensional flat pixel array to a three-dimensional curved surface arrangement. This dimensional change allows the pixel array to wrap around the curved path of the fan beam, effectively increasing the number of detectable slices and spatial resolution without proportionally increasing the cone angle, as the curvature distributes the pixels along the arc rather than requiring a larger flat area.
3Reliability
If image sensors are fixed firmly with high precision to maintain sensitivity uniformity, then sensitivity variations are reduced, but system complexity and maintenance difficulty increase
Solution Approach 1:
The curved surface configuration inherently provides mechanical support and positioning for the pixel array. The curvature itself acts as a structural element that maintains the geometric relationship between pixels and the X-ray source, reducing the need for complex external positioning mechanisms while ensuring uniform sensitivity across all pixels through the consistent angular relationships provided by the curved geometry.
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 configuration results in a more portable, cost-effective CT system with enhanced spatial and energy resolution, reduced X-ray dose, and lower maintenance requirements, suitable for early disease detection and 3D imaging.
Implementation Method 1
stacked configuration with a metal optical shield and scintillator film
Implementation Method 2
image sensors with a concave semiconductor substrate
Data Source
AI summary
A tomographic imaging system includes a source configured to irradiate an object; a first image sensor including a first semiconductor substrate having a first face upon which a monolithic first pixel array is located; and a gantry configured to hold the first image sensor and rotate the image sensor around the object about a first rotation axis, the first pixel array including a first plurality of pixels configured to receive light that travels through or from the object based on the irradiation, the first plurality of pixels of the first pixel array being arranged in one or more rows and a plurality of columns such that, a total number of the one or more rows is less than a total number of the plurality of columns, and the one or more rows extend in a first direction, the first image sensor being arranged such that an angle between the first direction and a second direction is greater than 45 degrees and equal to or less than 90 degrees, the second direction being a direction parallel to the rotation axis or a direction in which the object moves during analysis of the object by the imaging system.