Monoscopic Target Tracking Using Internal-External Motion Correlation
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Solution Overview
Problem
Existing radiation treatment systems face challenges in accurately tracking the movement of target regions within a patient's body during treatment to ensure precise delivery of radiation doses to the intended area, particularly due to factors like breathing and other bodily motions.
Innovation Solution
A sequential monoscopic tracking system using data from x-ray imagers acquires multiple flat-panel X-ray images from different angles over time, correlating internal and external markers to model the target's trajectory and adjust radiation delivery accordingly, employing mathematical models to estimate the target's 3D position and compensate for motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple x-ray images are acquired from different angles over time, then tracking precision is improved, but treatment time increases
Solution Approach 1:
The system performs preliminary actions by acquiring multiple x-ray images from different angles before treatment begins, and establishes correlation models between internal and external markers in advance. This allows the system to predict target position based on external marker data during treatment, avoiding the need to acquire multiple images during the actual treatment process.
Solution Approach 2:
The system creates a correlation model that copies the relationship between internal markers (attached to target) and external markers (attached to patient surface). Once this model is established from preliminary images, it can be used to estimate internal marker position from external marker data during treatment, replacing the need for continuous internal imaging.
2Measurement precision
If correlation models are fitted using multiple projections, then target position estimation accuracy is improved, but computational complexity increases
Solution Approach 1:
The computationally intensive task of fitting correlation models to multiple projections is performed in advance during setup, before treatment begins. This allows the system to use simpler, faster calculations during treatment by applying the pre-established models to external marker data, reducing real-time computational burden.
Solution Approach 2:
The correlation model acts as an intermediary that translates external marker positions (easily measured) into internal target position estimates. This mediator handles the complexity of multi-projection fitting in advance, allowing simple external marker tracking during treatment to yield accurate target position data.
3Reliability
If internal markers are tracked using multiple sequential images, then tracking reliability is improved, but radiation exposure increases
Solution Approach 1:
The system creates a correlation model that copies the spatial relationship between internal and external markers from preliminary imaging. During treatment, it tracks external markers (which receive minimal radiation) and uses the copied relationship to estimate internal marker position, avoiding the need for continuous internal marker imaging and reducing radiation exposure.
Solution Approach 2:
External markers serve as intermediaries that indirectly track internal target position without requiring direct imaging of internal markers during treatment. This intermediary approach maintains tracking reliability through the pre-established correlation model while minimizing radiation exposure by using external rather than internal imaging during treatment.
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 method enables precise tracking of the target's position, allowing for dynamic adjustment of radiation beams to align with the target, thereby improving the accuracy and effectiveness of radiation therapy by compensating for patient movements.
Implementation Method 1
A sequential monoscopic tracking system using data from x-ray imagers
Data Source
AI summary
A method of sequential monoscopic tracking is described. The method includes generating a plurality of projections of an internal target region within a body of a patient, the plurality of projections comprising projection data about a position of an internal target region of the patient. The method further includes generating external positional data about external motion of the body of the patient using one or more external sensors. The method further includes generating, by a processing device, a correlation model between the projection data and the external positional data by fitting the plurality of projections of the internal target region to the external positional data. The method further includes estimating the position of the internal target region at a later time using the correlation model.