Synchronized CBCT and Portal Imaging for Real-Time Dose Reconstruction

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Solution Overview

Problem

Current image-guided radiotherapy methods lack real-time patient anatomic information during treatment, leading to uncertainties due to organ movement, shrinkage, and deformation, which complicates accurate dose reconstruction and calibration.

Innovation Solution

A system incorporating a cone-beam computed tomography (CBCT) imaging system and megavoltage portal imaging, along with a processing system for generating 3D and 4D portal images, enabling real-time treatment dose reconstruction and adaptive planning by synchronizing kilovoltage and megavoltage imaging data for precise dose tracking and feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single pre-treatment CT scan is used to design treatment plan, then treatment planning can be completed, but large planning target margin and uncertainty in normal tissue dose occur due to patient variations during treatment

Engineering Contradiction:

Improvetreatment planning efficiencyVSAvoiddose reconstruction accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary imaging actions by acquiring multiple CT scans at different time points (pre-treatment, intra-treatment, and post-treatment) to capture patient anatomical changes before treatment begins. This allows the treatment plan to be designed with anticipation of variations, reducing the need for large planning margins while maintaining dose accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements continuous imaging and monitoring throughout the treatment process, transitioning from single pre-treatment scan to multiple time-point scans. This continuous action enables real-time tracking of patient anatomy changes, allowing for dynamic treatment plan adjustments that maintain precision without requiring excessive planning margins.

Inventive Principle:

Principle #20Continuity of useful action

2Measurement precision

If real-time imaging systems are implemented, then treatment precision and dose reconstruction accuracy improve, but system complexity and cost increase

Engineering Contradiction:

Improvedose reconstruction accuracyVSAvoidimaging system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system employs a multi-functional imaging platform that can perform various tasks including pre-treatment planning, intra-treatment monitoring, and post-treatment verification using the same hardware infrastructure. This universality reduces overall system complexity compared to having separate dedicated systems for each function, while still achieving high measurement precision through integrated real-time imaging capabilities.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple time-point imaging scans are performed, then patient anatomy changes can be captured and treatment plan adjusted, but treatment time and imaging duration increase

Engineering Contradiction:

Improveadaptive planning capabilityVSAvoidimaging and treatment time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system implements periodic imaging at strategically selected time points (pre-treatment baseline, intra-treatment milestones, and post-treatment verification) rather than continuous imaging. This periodic approach captures essential anatomical changes for adaptive planning while minimizing total imaging time and allowing treatment to proceed efficiently between scan points.

Inventive Principle:

Principle #19Periodic action

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 allows for accurate, real-time online and offline treatment dose reconstruction and adaptive planning, reducing uncertainties and improving treatment precision by incorporating continuous patient anatomy updates during radiotherapy sessions.

Implementation Method 1

a cone-beam computed tomography (CBCT) imaging system and megavoltage portal imaging

Methodology Applied

Scientific EffectX-ray: X-Ray

Implementation Method 2

megavoltage portal imaging, along with a processing system for generating 3D and 4D portal images

Methodology Applied

Scientific EffectElectromagnetic radiation detection:

Data Source

PatentUS8073104B2Portal and real time imaging for treatment verification

Publication Date: 2011.12.06 WILLIAM BEAUMONT HOSPITAL

AI summary

A system for radiotherapy includes a first imaging system and a second imaging system. The first imaging system generates projection images of an area of interest of an object, and the second imaging system generates portal images of the area of interest of the object synchronously with the generation of the projection images. The radiotherapy system further includes a processing system that receives data associated with the projection images and data associated with the portal images and reconstructs 3D and 4D portal images from the projection images and the portal images.