Dynamic Multileaf Collimator Trajectory Optimization for Arc Therapy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current radiotherapy systems face challenges in optimizing the trajectory of multileaf collimators during arc therapy to minimize unblocked radiation areas and protect organs at risk, leading to inefficiencies in dose delivery and potential harm to healthy tissues.
Innovation Solution
A system and method for determining a collimator trajectory that minimizes residual unblocked areas between the planning target volume and multileaf collimator leaves, using spatial measures and objective functions to calculate optimal collimator angles for each control point, thereby generating a precise arc therapy plan that reduces exposure to healthy tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the multileaf collimator uses fixed or simple rotation trajectories during arc therapy, then the device complexity is reduced and operation is simpler, but the unblocked radiation areas increase and organs at risk are exposed to higher doses
Solution Approach 1:
The collimator trajectory is transformed from fixed or simple rotation to a dynamically optimized path. The system calculates and implements a time-varying collimator angle trajectory that adapts to the gantry rotation, ensuring minimal unblocked areas throughout the arc therapy delivery. This dynamic control allows the collimator to actively respond to changing beam angles and protect organs at risk.
Solution Approach 2:
The optimal collimator trajectory is calculated in advance during treatment planning. The system pre-computes the sequence of collimator angles corresponding to each gantry angle based on the patient's anatomy and treatment goals. This preliminary optimization ensures that when therapy is delivered, the collimator is already positioned to minimize unblocked areas without requiring real-time complex calculations.
2Object-affected harmful factors
If the collimator trajectory is optimized to minimize unblocked areas, then the protection of organs at risk is improved, but the calculation complexity and treatment planning time increase
Solution Approach 1:
The complex mechanical optimization problem of finding optimal collimator trajectories is replaced with computational algorithms. The system uses automated software to calculate the optimal trajectory by simulating different paths and evaluating their effectiveness in minimizing unblocked areas. This substitution of computational methods for manual or trial-and-error optimization significantly reduces planning time while maintaining or improving treatment quality.
Solution Approach 2:
The treatment planning system automatically performs the optimization of collimator trajectories without requiring extensive manual intervention. The software self-adjusts the collimator angles based on predefined objectives and constraints, eliminating the need for planners to manually calculate and test multiple trajectories. This automation reduces both time and human effort while ensuring consistent optimization.
3Manufacturing precision
If the multileaf collimator rotates dynamically during arc therapy, then the precision of dose delivery is improved, but the control system complexity and operational difficulty increase
Solution Approach 1:
A control system intermediary is introduced that automatically translates treatment plan parameters into precise collimator rotation commands. The system acts as a mediator between the treatment planning software and the physical collimator mechanism, handling all the complexity of dynamic trajectory control. Operators simply select pre-calculated trajectories, and the intermediary system manages the complex coordination required for precise dose delivery.
Solution Approach 2:
Manual control of collimator rotation is replaced with automated electronic control systems. The precision required for dynamic collimator rotation during arc therapy is achieved through computer-controlled motors and sensors that precisely execute the pre-calculated trajectory. This substitution eliminates the need for operators to manually coordinate complex rotational movements while maintaining high precision dose delivery.
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
Systems and methods are provided for determining an angular trajectory for dynamically rotating a multileaf collimator during arc therapy. According to various embodiments, a suitable collimator trajectory may be determined based on the reduction or minimization of a residual unblocked area residing between a planning target volume and leaves of the multileaf collimator in the beam's eye view over the set of control points corresponding to an arc therapy plan. Various example methods are provided for determining collimator trajectories based on whitespace reduction, and for providing quantitative measures of whitespace optimization associated with a given trajectory. In some embodiments, the whitespace may be calculated using terms that account for the overlap of a planning target volume with an organ at risk of exposure.