Ion Arc Radiotherapy Planning With Optimized Energy Layer Transitions

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Solution Overview

Problem

Ion arc therapy in radiotherapy treatment is time-consuming due to the need for frequent adjustments between energy layers and irradiation directions, which compromises delivery efficiency without ensuring a suitable dose distribution.

Innovation Solution

The method involves creating ion-based radiotherapy treatment plans with a first and second part, where the first part is a sub-arc defined by a set of control points and energy levels, and the second part can be a static beam or a sub-arc with different energy levels, allowing for overlapping or opposite directions, to minimize time-consuming energy layer changes while maintaining effective dose distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If frequent adjustments between energy layers and irradiation directions are made to ensure suitable dose distribution, then dose distribution quality is improved, but delivery time increases

Engineering Contradiction:
Improvedose distribution qualityVSAvoiddelivery time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The arc therapy is segmented into multiple sub-arcs, each with a specific set of energy levels and irradiation directions. This segmentation allows the system to deliver treatment in discrete, optimized segments rather than requiring frequent adjustments throughout the entire arc, thereby maintaining dose distribution quality while reducing overall delivery time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Energy levels are pre-selected and grouped into sets that correspond to specific sub-arcs and irradiation directions. By determining the optimal energy level sets in advance through optimization algorithms, the system minimizes the need for time-consuming adjustments during actual delivery, thus reducing delivery time while ensuring appropriate dose distribution.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the number of energy layers is reduced to shorten delivery time, then delivery efficiency is improved, but dose distribution quality may deteriorate

Engineering Contradiction:
Improvedelivery efficiencyVSAvoiddose distribution quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention optimizes the parameters of energy levels by selecting specific sets of energy levels for different sub-arcs. This parameter optimization ensures that the minimum necessary number of energy layers are used to achieve the required dose distribution quality, thereby improving delivery efficiency without compromising treatment effectiveness.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If multiple irradiation directions are used to cover the target volume, then dose distribution uniformity is improved, but treatment complexity increases

Engineering Contradiction:
Improvedose distribution uniformityVSAvoidtreatment complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The treatment is divided into multiple sub-arcs, each covering specific irradiation directions. This segmentation simplifies the overall treatment planning and delivery by breaking down the complex multi-directional irradiation into manageable segments, each with optimized energy levels and directions, thereby reducing treatment complexity while maintaining dose distribution uniformity.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces delivery time by optimizing energy layer transitions and ensures a suitable dose distribution, making the treatment more efficient and robust to uncertainties in patient setup and anatomy.

Implementation Method 1

The particles are controlled in such a way that they will deposit most of their energy at specific depths in the patient so that the whole target will be covered. The depth of the Bragg peak in the patient can be controlled by adjusting the kinetic energy of the particles.

Methodology Applied
Scientific EffectBragg peak:

Implementation Method 2

The lateral position of the Bragg peak can be controlled using electromagnets to deflect the focused beam.

Methodology Applied
Scientific EffectElectromagnetic deflection: Lorentz Force

Data Source

PatentEP4238609B1Radiotherapy treatment planning for ion arcs
Publication Date: 2025.10.29 RAYSEARCH LAB
  • EP4238609B1 patent drawingFigure 1a~1d
  • EP4238609B1 patent drawingFigure 2
  • EP4238609B1 patent drawingFigure 3~4

AI summary

A method of creating an ion-based radiotherapy treatment plan includes a spotweight optimization procedure arranged to create the plan involving an arc as a combination of one or more sub-arcs and possibly a static beam wherein the one or more sub-arcs either overlap or have different directions. The method includes selecting the first and second sets of energy levels together.