4D Radiotherapy Planning With Dynamic Beam Tracking

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Solution Overview

Problem

Existing dynamic target tracking methods in radiation therapy fail to account for the relative movement of organs at risk with respect to the target, leading to potential radiation exposure during irregular breathing cycles, and do not optimize dose distribution effectively across different phases of the cycle.

Innovation Solution

A method for radiation therapy treatment planning that considers both the movement of the target and deformed patient geometry by optimizing beam setups for each phase, using 4D imaging and dose-based optimization functions to minimize radiation to organs at risk and ensure accurate targeting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If margins are added around the target to account for position uncertainty, then the minimum dose to the whole target is ensured, but unwanted radiation to surrounding tissue increases

Engineering Contradiction:
Improveminimum dose to targetVSAvoidradiation to surrounding tissue
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamic target tracking to continuously adjust beam positioning based on real-time target location feedback. This dynamic adaptation eliminates the need for static safety margins, as the beam actively follows the target throughout treatment, ensuring full target coverage while minimizing exposure to surrounding healthy tissue.

Inventive Principle:
Principle #15Dynamics

2Reliability

If robust planning is used to account for uncertainties in target and organ position, then a minimum quality plan is achieved for worst-case scenarios, but the dose to healthy tissue increases

Engineering Contradiction:
Improveplan quality under uncertaintyVSAvoiddose to healthy tissue
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements real-time feedback through dynamic target tracking systems that continuously monitor target position and adjust beam delivery accordingly. This feedback mechanism replaces robust planning's conservative worst-case approach with actual measured data, allowing precise target coverage without the need to over-compensate for potential uncertainties, thereby reducing healthy tissue exposure.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If dynamic target tracking is used to redirect beams as the target moves, then the radiation hits the target more accurately, but the system complexity increases

Engineering Contradiction:
Improvetarget positioning accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs an intermediary tracking system that acts as a mediator between the target and the beam delivery system. This intermediary component captures real-time target position data and translates it into appropriate beam adjustment commands, simplifying the overall control architecture while maintaining high positioning accuracy through dedicated tracking functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Object-affected harmful factors

If treatment margins are reduced to spare healthy tissue, then radiation exposure to surrounding tissue decreases, but the uncertainty in target coverage increases

Engineering Contradiction:
Improveradiation to healthy tissueVSAvoidtarget coverage assurance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent uses dynamic target tracking to maintain reliable target coverage with reduced margins by continuously adapting beam position to the actual target location. This real-time adjustment ensures that even with smaller safety margins, the target receives the intended dose while healthy tissue exposure is minimized, as the beam precisely follows the target throughout treatment.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3586920B1System and method for radiation treatment planning
Publication Date: 2025.11.26 RAYSEARCH LAB
  • EP3586920B1 patent drawingFigure 1a~1c
  • EP3586920B1 patent drawingFigure 2~4
  • EP3586920B1 patent drawing

AI summary

A method of radiotherapy treatment planning involves dynamic target tracking and beam redirection. A set of 3D images of a patient reflecting a movement of the patient is obtained, and each image is deformably registered with one reference image. The accumulated dose is calculated as the sum of the dose distribution over all phases in dependence of the patient movement and the model of the delivery machine, the dose distribution for each phase being deformed by means of the deformation map for the respective phase, to match the reference image.