Non-Invasive Tumor Tracking via Iterative X-Ray Reconstruction
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Solution Overview
Problem
Current cancer radiation therapy is hindered by unpredictable tumor motion during treatment due to patient motion, requiring invasive marker implantation and resulting in sub-optimal radiation delivery, especially for lung tumors with large respiratory motion ranges, where existing markerless tracking methods face challenges with tumor visibility and accuracy.
Innovation Solution
A method for real-time tracking of tumors using a few spatially distributed X-ray projections, incorporating a prior image and iterative reconstruction techniques to reconstruct the target's motion phases, allowing for accurate localization without invasive markers, utilizing 4D cone beam CT and respiratory motion sensors to track tumor movement within the body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive marker implantation is used to track tumor motion, then tumor localization accuracy is improved, but patient trauma and treatment complexity increase
Solution Approach 1:
The patent extracts the tracking function from invasive markers and implements it through non-invasive X-ray imaging of the tumor itself. The tumor's natural radiopacity is utilized for tracking without requiring foreign objects, thereby eliminating patient trauma while maintaining localization accuracy through image processing and motion analysis techniques
Solution Approach 2:
The patent introduces X-ray imaging as an intermediary between the tumor and the tracking system. Instead of directly attaching markers to the tumor, the system uses X-ray projections to capture tumor position indirectly, processing these images to extract motion information. This intermediary approach eliminates the need for invasive intervention while enabling continuous tracking
2Object-affected harmful factors
If existing markerless tracking methods are used, then patient trauma is reduced, but tumor visibility and tracking accuracy deteriorate
Solution Approach 1:
The patent performs preliminary actions by acquiring multiple X-ray projections at different angles and time points before attempting tumor localization. These pre-acquired images are processed to create a comprehensive dataset that enhances tumor visibility and enables accurate tracking without requiring invasive markers
Solution Approach 2:
The patent transitions from 2D X-ray projections to 3D tumor localization by processing multiple projections taken at different angles. This dimensional transformation allows the system to reconstruct tumor position in three-dimensional space, significantly improving tracking accuracy while maintaining non-invasive operation
3Device complexity
If standard X-ray imaging is used for tumor tracking, then equipment complexity is reduced, but tracking precision and real-time capability worsen
Solution Approach 1:
The patent implements continuous X-ray imaging during treatment delivery, acquiring multiple projections in rapid succession. This continuous imaging approach provides real-time tumor position data throughout the treatment process, enabling dynamic tracking without requiring complex specialized equipment
Solution Approach 2:
The patent replaces complex mechanical tracking systems with an imaging-based approach. Instead of using mechanical sensors or markers attached to the tumor, the system uses X-ray imaging combined with computational methods to track tumor motion, thereby reducing equipment complexity while maintaining or improving tracking precision
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 enables non-invasive, robust, and accurate real-time tumor tracking with reduced radiation dose, improving tumor localization accuracy to within 2 mm, and is applicable to lung cancer radiotherapy, addressing the limitations of existing markerless tracking methods by enhancing tumor visibility and tracking accuracy even in challenging anatomical conditions.
Implementation Method 1
acquiring a few spatially distributed x-ray projections of the target area
Implementation Method 2
performing an iterative reconstruction of the image for each of the motion phases
Data Source
AI summary
A method for tracking a target located within a body, whilst scanning the body using X-ray projections, the method including the steps of: (a) providing a first prior image of the body and target indicating their relative position; (b) iteratively performing, for a series of time intervals, the steps of: (i) acquiring a few spatially distributed x-ray projections of the target area; (ii) determining one of a series of motion phases for each x-ray projection; (iii) performing an iterative reconstruction of the image for each of the motion phases; and (iv) outputting a resultant image for a current time interval.