Dynamic Collimator Aperture for Tomosynthesis X-Ray Beam Control
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Solution Overview
Problem
Conventional tomosynthesis apparatuses face issues with suboptimal exposure of the flat panel detector due to insufficient collimation, leading to both underexposure and overexposure from different tomosynthesis angles, which affects image quality and radiation protection.
Innovation Solution
The tomosynthesis apparatus features a variable collimator diaphragm aperture that adjusts its shape and size based on the tomosynthesis angle, ensuring the x-ray beam expansion matches the detector dimensions, using a projection matrix to calculate the optimal aperture shape and size for each angle, thereby preventing overexposure and ensuring full detector utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed collimator diaphragm is used in conventional tomosynthesis apparatuses, then the device complexity is reduced, but the detector exposure becomes suboptimal at different tomosynthesis angles due to insufficient collimation
Solution Approach 1:
The collimator diaphragm aperture is made dynamically adjustable rather than fixed. The system automatically adapts the aperture shape and size based on the current tomosynthesis angle, transitioning from a static to a dynamic collimation system that maintains optimal detector exposure across all imaging angles.
Solution Approach 2:
The collimator diaphragm parameters (aperture shape and size) are changed according to the tomosynthesis angle. The system modifies these geometric parameters dynamically to match the beam geometry at each angle, ensuring optimal detector coverage and preventing both overexposure and underexposure.
2Reliability
If the collimator diaphragm aperture is not adapted to the tomosynthesis angle, then the device operation is simplified, but the detector experiences overexposure or underexposure from different angles
Solution Approach 1:
The collimator diaphragm system performs self-adjustment based on the tomosynthesis angle without requiring manual intervention. The automatic adaptation mechanism ensures consistent detector exposure across all angles while eliminating the need for operator configuration of the collimator settings.
Solution Approach 2:
The system incorporates feedback mechanisms to monitor and adjust the collimator diaphragm aperture based on the actual tomosynthesis angle. This ensures that the aperture remains optimally configured for the current imaging geometry, maintaining reliable detector exposure consistency.
3Manufacturing precision
If a fixed collimator diaphragm is used, then the manufacturing cost is reduced, but image quality deteriorates due to suboptimal detector exposure at various angles
Solution Approach 1:
The collimator diaphragm is designed with dynamic adjustment capabilities, allowing the aperture to change shape and size according to the tomosynthesis angle. This dynamic design improves manufacturing precision for detector exposure while accommodating the added complexity through automated control mechanisms.
Solution Approach 2:
The system enables continuous parameter changes in the collimator diaphragm aperture to match different imaging geometries. This allows optimal detector exposure at all angles while the automated parameter adjustment reduces the manual manufacturing complexity.
4Object-affected harmful factors
If the x-ray beam is not properly collimated at different angles, then the radiation protection is insufficient, but the detector utilization is suboptimal
Solution Approach 1:
The collimator diaphragm aperture parameters are dynamically adjusted to match the x-ray beam geometry at each tomosynthesis angle. This ensures that the beam is properly collimated to the detector area, preventing radiation waste and optimizing detector utilization across all imaging angles.
Solution Approach 2:
The system replaces manual mechanical collimator adjustment with an automated control system that calculates and applies the optimal aperture settings based on the tomosynthesis angle. This substitution improves radiation protection while maximizing detector area utilization through precise, automated collimation.
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 solution ensures optimal exposure of the flat panel detector at every tomosynthesis angle, preventing overexposure and maximizing image field while providing the best radiation protection for personnel and patients, thereby improving image quality and safety.
Implementation Method 1
A collimator diaphragm (14) has a diaphragm aperture (30) that limits the expansion of the x-ray beam (8) at the location of the flat panel detector (12)
Implementation Method 2
an x-ray source (4) that generates an x-ray beam (8) emanating from a focus (6), which is detected by a flat panel detector (12)
Data Source
AI summary
A tomosynthesis apparatus has an x-ray source that generates an x-ray beam emanating from a focus, which is received by a flat panel detector. To set a tomosynthesis angle, the position of the central axis of the x-ray beam of the x-ray source is variable. A collimator diaphragm has a diaphragm aperture that limits the expansion of the x-ray beam at the location of the flat panel detector. The collimator diaphragm is arranged in the beam path between the focus and the flat panel detector. The shape and size of the diaphragm aperture are dynamically varied (adjusted) dependent on the changing tomosynthesis angle, such that the expansion of the x-ray beam at the location of the flat panel detector always essentially corresponds to the detector dimensions.