Medical Image Processing for Radiotherapy Focus Tracking
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Solution Overview
Problem
Current radiotherapy techniques face challenges in accurately tracking focus displacement during respiration due to unclear X-ray fluoroscopic images caused by reduced radiation intensity, leading to potential damage to normal tissues and low reliability in tracking methods such as marker implantation and surface motion measurement.
Innovation Solution
A medical image processing technique that reconstructs three-dimensional moving images and identifies characteristic regions within the images to correlate and correct focus displacement in real-time, using a combination of reconstructed and fluoroscopic images to accurately determine the focus position and timing for precise beam irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If radiation intensity is reduced to attenuate patient exposure, then harmful radiation exposure is decreased, but focus visibility in fluoroscopic images deteriorates
Solution Approach 1:
The patent introduces an internal body portion as an intermediary object that can be clearly imaged in fluoroscopic images. By tracking the displacement of this intermediary (internal body portion) rather than directly tracking the focus, the system can infer focus position indirectly. This resolves the contradiction by providing a visible tracking target without requiring high radiation intensity.
Solution Approach 2:
The patent creates a virtual copy of the internal body portion's displacement pattern and applies it to track the focus position. By reconstructing the focus trajectory based on the correlated displacement of the internal body portion, the system obtains precise focus tracking information without directly imaging the focus at high radiation intensity.
2Measurement precision
If marker implantation is performed to track focus displacement, then focus tracking precision is improved, but surgical burden on patient increases
Solution Approach 1:
The patent utilizes the patient's own internal body portion (such as diaphragm or lung tissue) as the tracking reference, eliminating the need for external markers or implants. The internal body portion naturally moves with respiration and correlates with focus displacement, providing self-contained tracking without additional surgical intervention.
3Reliability
If body surface motion is measured using laser range finder, then focus displacement tracking is enabled, but reliability decreases due to unstable relationship between surface motion and focus position
Solution Approach 1:
The patent transitions from tracking two-dimensional body surface motion to tracking three-dimensional internal body portion displacement that is directly correlated with focus position. By moving the measurement plane from the external surface to internal structures that move in concert with the focus, the system achieves more reliable and accurate tracking.
Data Source
AI summary
A medical image processing apparatus, includes: a reconstructed moving image obtainer that obtains a reconstructed moving image; a focus region identifier that identifies a first focus region corresponding to the designated focus; a fluoroscopic moving image obtainer that obtains at least one-period data on a fluoroscopic moving image; a second characteristics identifier that identifies each of two or more second characteristics regions corresponding to the internal body portion; a comparison selector that compares the two or more first characteristic regions; a conversion parameter calculation unit that calculates a conversion parameter for converting the first characteristic region.