Adaptive Radiation Therapy for Moving Targets

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Solution Overview

Problem

Current radiation therapy methods for moving targets, such as tumors, are inefficient as they rely on prior knowledge of the target's location, period, and phase, and struggle to adapt to changes in patient anatomy during treatment, leading to suboptimal dose distribution and increased motion-reproducibility requirements for patients.

Innovation Solution

A system that generates multiple treatment plans and dynamically switches between them based on real-time data on the patient's anatomical motion, allowing for continuous radiation delivery without relying on pre-defined target trajectories, using a multi-leaf collimator and other radiation therapy system components to adjust parameters like leaf patterns, gantry speed, and patient support movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If gating method is used to treat moving target, then radiation is delivered only when target is within specified window, but treatment efficiency is reduced because target is irradiated only for periodic intervals

Engineering Contradiction:
Improvedose delivery precisionVSAvoidtreatment efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system dynamically adjusts the treatment plan by switching between multiple pre-planned radiation delivery patterns based on the real-time breathing phase detected during treatment. This allows continuous adaptation to target motion without interrupting radiation delivery, resolving the contradiction between precise dose delivery and treatment efficiency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the delivery parameters (such as multi-leaf collimator positions, gantry angles, and radiation intensity) based on detected breathing phase. By modifying these parameters in real-time according to target position, the system maintains dose precision while eliminating the periodic interruptions inherent in gating methods

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If breathing synchronized delivery with rigidly defined track is used, then anticipated track is utilized for target motion, but following strictly defined pattern is difficult for large portion of patients

Engineering Contradiction:
Improvedose distribution accuracyVSAvoidpatient compliance
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

Instead of requiring patients to follow a rigid breathing pattern, the system dynamically adapts the treatment delivery to match the patient's actual breathing movements. Multiple treatment plans are prepared in advance covering different breathing scenarios, and the system automatically selects the appropriate plan based on real-time motion detection, making the treatment comfortable for patients while maintaining dose accuracy

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Rather than forcing the patient to conform to a predetermined breathing track, the system inverts the approach by having the treatment plan conform to the patient's natural breathing pattern. The rigid treatment protocol is replaced with flexible, adaptive planning that accommodates patient-specific motion characteristics

Inventive Principle:
Principle #13The other way round (Inversion)

3Productivity

If multiple treatment plans are generated and dynamically switched based on real-time anatomical motion data, then radiation delivery is continuous and adaptive, but system complexity increases

Engineering Contradiction:
Improvetreatment efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Multiple treatment plans are generated in advance during the planning phase, each corresponding to different breathing phases or motion scenarios. This preliminary preparation eliminates the need for complex real-time calculations during treatment delivery, reducing computational complexity while maintaining high treatment efficiency through pre-computed adaptive plans

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The treatment delivery is segmented into multiple discrete plans, each optimized for specific breathing phases. This segmentation allows the complex problem of continuous adaptive treatment to be broken down into manageable, pre-planned segments that can be easily switched between based on detected motion, simplifying the control system architecture

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP1977788B1System of delivering radiation therapy to a moving region of interest
Publication Date: 2011.05.04 TOMOTHERAPY INC
  • EP1977788B1 patent drawingFigure 1
  • EP1977788B1 patent drawingFigure 2
  • EP1977788B1 patent drawingFigure 3

AI summary

A system for and method of delivering radiation therapy to a moving region of interest is disclosed. The method, in one implementation, includes the acts of generating a plurality of treatment plans for providing radiation therapy, delivering radiation therapy to the patient following one of the plurality of treatment plans, monitoring the patient while providing radiation therapy, and changing the treatment plan based at least in part on monitoring the patient.