Radiotherapy Couch Positioning at Variable Gamma Angles
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Solution Overview
Problem
The accuracy of radiotherapy positioning is compromised when the gamma angle is adjusted during treatment, as existing methods fail to accurately align the target point with the equipment isocenter at different angles, leading to reduced treatment efficacy due to the fixed gamma angle used during CT imaging.
Innovation Solution
A computer-based positioning method that calculates and adjusts the treatment couch coordinates based on the gamma angle, determining the relative positions between the target point, imaging point, and equipment isocenter to ensure accurate alignment at varying gamma angles, using a gamma angle adjustment device to rotate the patient's posture accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the gamma angle is adjusted during radiotherapy treatment, then the treatment can accommodate different patient postures and improve treatment versatility, but the positioning accuracy deteriorates because existing methods cannot accurately align the target point with the equipment isocenter at different angles
Solution Approach 1:
The patent transforms the static positioning method into a dynamic one by introducing real-time gamma angle detection and coordinate transformation. The system dynamically adjusts the treatment couch coordinates based on the actual gamma angle, enabling accurate positioning at any angle rather than being fixed at 90 degrees.
Solution Approach 2:
The patent changes the parameter of gamma angle from a fixed value (90 degrees) to a variable parameter that can be detected and adjusted. By detecting the actual gamma angle and using it to calculate corrected treatment couch coordinates, the system adapts to different angles while maintaining positioning accuracy.
2Measurement precision
If image registration is performed between IGS image and DRR image to determine position deviation, then the target point can be aligned with the equipment isocenter at fixed gamma angle, but the positioning accuracy deteriorates when gamma angle is adjusted because the registration does not account for angle changes
Solution Approach 1:
The patent introduces a feedback mechanism where the actual gamma angle is detected and fed back into the positioning calculation. The system uses this feedback to correct the treatment couch coordinates, ensuring that positioning accuracy is maintained even when the gamma angle deviates from the standard 90 degrees.
Solution Approach 2:
The patent performs preliminary detection of the gamma angle and calculates the corrected treatment couch coordinates before executing the positioning. This preliminary action ensures that the positioning is accurate from the start, even when the gamma angle is not at the standard value.
Data Source
AI summary
A positioning method realized by a computer including acquiring a gamma angle for treatment; acquiring first coordinates of a treatment couch, the first coordinates being coordinates of the treatment couch when a preset shooting point coincides with an imaging point of an image guidance system (IGS); determining a first relative position between a target point of an affected part and the imaging point according to the gamma angle for treatment; acquiring a second relative position between the imaging point and an equipment isocenter; calculating second coordinates of the treatment couch at the gamma angle for treatment when the target point coincides with the equipment isocenter according to the first coordinates, the first relative position and the second relative position; and adjusting a position of the treatment couch according to the second coordinates.