Radiotherapy Field Delivery Optimization for Time-Dose Balance

Solution Overview

Problem

Existing radiotherapy treatment planning systems struggle to optimize treatment time while maintaining clinically acceptable dosimetry, particularly in spot scanning techniques, leading to suboptimal dose redistribution and inefficient field delivery.

Innovation Solution

A computer-implemented method and system that adjusts beam currents and spot distribution based on machine-specific parameters to optimize treatment time and dosimetry, using a graphical user interface to balance delivery time and dosimetric objectives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If spot scanning treatment planning optimizes for dose distribution by removing spots below a certain monitor unit threshold, then the dose to surrounding healthy tissue is minimized, but the treatment time is extended and field delivery efficiency is reduced

Engineering Contradiction:

Improvedose to surrounding healthy tissueVSAvoidtreatment time

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent changes the optimization parameter from purely dosimetric (monitor unit threshold) to include a composite cost function that incorporates both dosimetric quality and delivery time components. This allows the system to evaluate spots based on both their dosimetric contribution and their impact on treatment time, enabling optimization of both objectives simultaneously rather than sequentially

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamic weighting factors that allow the relative importance of dosimetric objectives versus delivery time objectives to be adjusted during optimization. The cost function dynamically balances these competing objectives based on user-defined weights, enabling flexible trade-offs between treatment time and dosimetric quality without requiring separate optimization passes

Inventive Principle:

Principle #15Dynamics

2Device complexity

If existing treatment planning solutions remove spots below a monitor unit threshold to simplify delivery, then the number of spots is reduced, but the dose redistribution is not optimal for either plan quality or field delivery time

Engineering Contradiction:

Improvenumber of spotsVSAvoidplan quality

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent transforms the spot selection criterion from a simple monitor unit threshold to a composite cost metric that includes both dosimetric quality measures and delivery time considerations. This parameter change enables the system to identify spots for removal based on their overall contribution to both plan quality and delivery efficiency, rather than solely on dose magnitude

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback mechanism where the cost function evaluates the impact of spot removal on both dosimetric objectives and delivery time objectives. The optimization process iteratively adjusts spot selection based on this feedback, ensuring that removed spots do not significantly degrade plan quality while achieving delivery time reductions

Inventive Principle:

Principle #23Feedback

3Object-affected harmful factors

If treatment planning prioritizes minimizing dose to surrounding tissue, then normal tissue toxicities are reduced, but the overall treatment time cannot be reduced to accommodate breath-hold techniques

Engineering Contradiction:

Improvenormal tissue toxicitiesVSAvoidoverall treatment time

Core Design Contradiction:

Object-affected harmful factorsVSDuration of action of moving object

Solution Approach 1:

The patent introduces dynamic weighting factors that allow the relative importance of dosimetric objectives versus delivery time objectives to be adjusted during optimization. The cost function dynamically balances these competing objectives based on user-defined weights, enabling flexible trade-offs between treatment time and dosimetric quality without requiring separate optimization passes

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the optimization parameter from purely dosimetric (monitor unit threshold) to include a composite cost function that incorporates both dosimetric quality and delivery time components. This allows the system to evaluate spots based on both their dosimetric contribution and their impact on treatment time, enabling optimization of both objectives simultaneously rather than sequentially

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP4011443B1System and method for radiotherapy field delivery time optimization

Publication Date: 2025.09.03 VARIAN MEDICAL SYSTEMS INC

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AI summary

Treatment fields can be produced as part of a treatment plan that achieves a desired balance between field delivery time and dose based on machine parameters and knowledge, such as machine-specific beam production, transport and scanning logic, and/or a maximum treatment time value. The treatment parameters can be adjusted using a graphical user interface so that treatment time or dosimetry is prioritized. As a result, the overall treatment time is reduced, and hence treatment quality and patient experience are improved.