Radiotherapy Beam Correction for Patient Setup Errors
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Solution Overview
Problem
Current radiation therapy systems face challenges in precisely positioning a tumor or target volume due to changes in its position within a patient, particularly when using treatment tables with limited degrees of freedom, leading to increased treatment time and potential patient disturbance, as well as the need for time-consuming dose recompute in some methods.
Innovation Solution
A method and apparatus that utilize a processor to receive and analyze information about treatment plans, patient volumes, and constraints to define alternative positions and beam adjustments for the gantry and collimator, minimizing the need for patient support changes and optimizing beam intersections to compensate for six-degree movements of the tumor or target volume, thereby reducing treatment time and patient disturbance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a robotic couch with six degrees of freedom is used to correct patient position, then positioning precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the position correction into two parts: (1) a one-time six-degree-of-freedom correction of the patient support to account for target volume shifts, and (2) beam-specific adjustments of gantry and collimator positions. This segmentation reduces the complexity of continuously adjusting the patient support for each beam direction.
Solution Approach 2:
The patent applies preliminary action by calculating and applying the six-degree-of-freedom patient support correction before beam delivery begins. This preliminary correction accounts for target volume shifts in advance, eliminating the need for complex real-time adjustments during treatment.
2Manufacturing precision
If the treatment table position is changed for each beam direction, then positioning precision is improved, but treatment time increases
Solution Approach 1:
The patent performs the six-degree-of-freedom patient support correction as a one-time preliminary action before beam delivery. This eliminates the need to reposition the table for each beam direction, significantly reducing treatment time while maintaining positioning precision through the initial correction and subsequent beam adjustments.
3Manufacturing precision
If dose recompute is performed after table position changes, then positioning precision is improved, but treatment time increases
Solution Approach 1:
The patent uses feedback from imaging to determine the actual position of the target volume and calculates the necessary six-degree-of-freedom correction. This feedback mechanism allows the system to automatically adjust the patient support position without requiring time-consuming dose recomputation, as the correction is applied directly based on the imaging feedback.
Data Source
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AI summary
In some embodiments, a method includes receiving (602), in a processor (133), information indicative of (i) a treatment plan defining planned treatment beams, (ii) a patient volume relative to a reference, (iii) ideal intersections (1010) of the planned treatment beams (1008) with the patient volume at the time the patient is to be treated, (iv) any constraints that prevent achievement of the recommended repositioning using only the patient support (120), (v) an allowable change to a gantry position from a planned value and an allowable change to a collimator position from a planned value; defining (604), in the processor, a plurality of alternatives (1100) based at least in part on the information indicative of any constraints of the patient support and the information indicative of allowable movement of the gantry and collimator, each alternative defining a modified patient support position and modified beams, each modified beam being based at least in part on a respective one of the planned treatment beams, the change to the position of the gantry (112) for the respective planned treatment beam and the change to the position of the collimator(200) for the respective planned treatment beam; determining (606), in the processor, for each modified beam (1028) of each alternative, an intersection (1030) of the patient volume and the modified beam, with the patient volume positioned on the patient support and the patient support having the modified patient support position defined by the alternative; and defining (608), in the processor, for each alternative, a measure of difference between the ideal intersections (1010) and the intersections (1030) for the modified beams (1028) of the alternative.