Radiotherapy Planning for FLASH Pencil Beam Spot Clustering

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Solution Overview

Problem

Conventional radiotherapy methods cause significant damage to healthy tissue due to lower dose rates, while FLASH therapy, with higher dose rates, reduces this damage but requires optimization to enhance its effect.

Innovation Solution

A computer-based method for radiotherapy planning that optimizes the delivery of pencil beam scanning by grouping spots into clusters to enhance the FLASH effect, using an optimization problem that considers spot placement, order, and weights to deliver doses consecutively within short intervals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional radiotherapy is delivered at lower dose rates, then the treatment can be administered safely, but significant damage is caused to healthy tissue

Engineering Contradiction:

Improvedamage to healthy tissueVSAvoiddose rate

Core Design Contradiction:

Object-affected harmful factorsVSSpeed

Solution Approach 1:

The patent changes the dose rate parameter from conventional levels (a few Gy per minute) to ultra-high FLASH levels (at least 40 Gy/s), transforming the physical delivery conditions to achieve differential protection of healthy tissue while maintaining tumour effectiveness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The treatment delivers radiation in extremely short time intervals (less than a second for the entire dose), using periodic ultra-short duration beams to create the FLASH effect that spares healthy tissue

Inventive Principle:

Principle #19Periodic action

2Object-affected harmful factors

If FLASH therapy is delivered at ultra-high dose rates, then damage to healthy tissue is reduced, but the time structure of dose delivery must be optimized to maintain the FLASH effect

Engineering Contradiction:

Improvedamage to healthy tissueVSAvoidoptimization of spot delivery pattern

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the treatment field into multiple spots arranged in clusters, where each cluster contains adjacent spots that will be delivered consecutively. This segmentation allows optimization of the delivery pattern to maintain ultra-high dose rates within clusters while managing the overall treatment complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary optimization of the spot delivery pattern before treatment, determining the specific sequence and clustering of spots to ensure consecutive delivery within clusters. This pre-planning ensures the FLASH effect is maintained without requiring real-time complex adjustments during treatment

Inventive Principle:

Principle #10Preliminary action

3Speed

If spots are delivered line by line in conventional pencil beam scanning, then the beam can be controlled systematically, but the FLASH effect is reduced because adjacent spots are delivered with longer time intervals

Engineering Contradiction:

Improvedose delivery speedVSAvoidloss of FLASH effect

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional line-by-line scanning approach by delivering spots in clusters where adjacent spots are treated consecutively rather than sequentially across lines. This reversal of the delivery pattern ensures that the time interval between adjacent spots remains extremely short, maintaining the FLASH effect while still using systematic beam control

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS12472378B2Method, computer program product and computer system for radiotherapy planning, and radiotherapy delivery system

Publication Date: 2025.11.18 RAYSEARCH LAB

AI summary

A radiotherapy treatment planning method for achieving a FLASH radiotherapy treatment plan involves optimizing the plan using an optimization problem that has been designed to maximize the part of the irradiation that will be delivered under FLASH conditions, in particular to an organ at risk, to minimize the damage to the organ at risk.