Four-Dimensional CT Scan Region Segmentation
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Solution Overview
Problem
Traditional imaging devices, such as CT scanners, face limitations in performing long-duration 4D scans due to heat capacity constraints and subject exposure to high radiation doses, especially when capturing cyclic movements like cardiac or respiratory movements.
Innovation Solution
The method involves performing a first scan on a region with minimal cyclic movement and a second 4D scan on a region with significant cyclic movement, using different scan parameters, including varying pitches, to reduce scan time and radiation exposure. Movement information is obtained during the second scan to reconstruct a final image set combining both scans.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional CT scanner performs a 4D scan on the entire ROI to capture cyclic movements, then the position and volume of target regions can be identified across different phases, but the scan time becomes excessively long and the radiation dose to the subject increases significantly
Solution Approach 1:
The ROI is divided into multiple sub-regions, each scanned with appropriate parameters. Regions with significant cyclic movement are scanned with motion compensation, while regions with minimal movement are scanned more quickly, reducing overall scan time while maintaining accuracy where needed.
Solution Approach 2:
Different scan parameters are applied to different sub-regions based on their movement characteristics. The first scan uses parameters optimized for regions with minimal cyclic movement, while the second scan uses parameters optimized for regions with significant cyclic movement, achieving local optimization of both speed and accuracy.
2Measurement precision
If a traditional CT scanner performs a 4D scan on the entire ROI to capture cyclic movements, then the position and volume of target regions can be identified across different phases, but the radiation dose received by the subject becomes excessively high
Solution Approach 1:
The ROI is segmented into sub-regions with different movement characteristics, allowing selective application of scan protocols. This reduces the total volume scanned with high-dose motion-compensated protocols, thereby reducing overall radiation exposure while maintaining diagnostic accuracy in critical areas.
Solution Approach 2:
Different radiation doses are applied to different sub-regions based on their clinical importance and movement characteristics. Regions with minimal movement receive lower doses via faster scanning, while regions with significant movement receive higher doses only where necessary for accurate target identification.
3Productivity
If the scan parameters are optimized for regions with minimal cyclic movement, then the scan speed increases, but the ability to accurately capture moving target regions deteriorates
Solution Approach 1:
The scanning process is segmented into two separate scans: a first scan that prioritizes speed for regions with minimal movement, and a second scan that prioritizes accuracy with motion compensation for regions with significant cyclic movement. This segmentation allows each scan to be optimized for its specific purpose.
Solution Approach 2:
The system dynamically adjusts scan parameters based on the specific characteristics of each sub-region. Motion compensation is applied selectively to regions where it is needed, while regions with minimal movement are scanned using faster, simpler protocols, creating a dynamic adaptation to local requirements.
4Measurement precision
If motion compensation is applied during the scan, then the ability to capture moving target regions improves, but the complexity of the scanning system increases
Solution Approach 1:
Motion compensation is segmented and applied only to specific sub-regions where cyclic movement occurs, rather than being applied uniformly across the entire ROI. This reduces the overall complexity of the motion compensation system while maintaining accuracy where needed.
Solution Approach 2:
Instead of applying full motion compensation across the entire ROI, the system applies partial motion compensation only to the extent necessary for regions with significant cyclic movement, reducing system complexity while achieving sufficient accuracy for diagnostic purposes.
Data Source
AI summary
Systems and methods for four-dimensional CT scan are provided. The methods may include determining a first region of a subject and a second region. A movement of the subject may occur within the second region. The methods may further include generating a first image set by performing, based on a first operation parameter corresponding to a first scan, the first scan on the first region of the subject, and generating a second image set by performing, based on a second operation parameter corresponding to a second scan, the second scan on a second region of the subject. The methods may further include obtaining movement information corresponding to the movement of the subject and determining a final image set based on the first image set, the movement information, and the second image set.