Real-time margin adaptation for radiotherapy
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Solution Overview
Problem
Current radiotherapy techniques for moving tumors rely on static treatment margins, which can lead to inaccurate dose distributions due to patient setup uncertainties and intrafractional tumor motion, potentially resulting in under-dosing the tumor or over-dosing healthy tissue, despite the availability of real-time imaging data.
Innovation Solution
A system and method for real-time treatment margin modification using in-treatment imaging, where a processor generates treatment plans based on internal and gross tumor volumes, and adjusts margins dynamically based on a tracking confidence parameter, allowing for adaptation between static and minimal margin plans during radiation delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If static treatment margins are used, then treatment planning is simplified and delivery is faster, but dose distribution accuracy deteriorates due to tumor motion and setup uncertainties
Solution Approach 1:
The patent implements dynamic treatment margins that adapt in real-time based on tracked tumor position and localization confidence. Instead of using fixed static margins throughout treatment delivery, the system continuously adjusts margin sizes according to current tumor location accuracy, thereby maintaining dose distribution precision while enabling faster delivery through automated real-time adaptation.
Solution Approach 2:
The system employs real-time feedback from in-treatment imaging to monitor tumor position and localization confidence. This feedback loop enables continuous adjustment of treatment margins during radiation delivery, allowing the system to respond to actual tumor motion and positioning accuracy, thus maintaining dose accuracy without requiring overly conservative static margins.
2Manufacturing precision
If real-time imaging and dynamic margin adaptation are implemented, then dose distribution accuracy is improved, but system complexity increases
Solution Approach 1:
The patent utilizes existing multi-functional components in the linear accelerator system, such as the electronic portal imaging device (EPID) that serves both as an imaging tool for tumor localization and as part of the radiation delivery system. The same imaging hardware and processing infrastructure are leveraged for multiple purposes, reducing the need for additional dedicated equipment and thereby limiting the increase in system complexity.
Solution Approach 2:
The system employs automated algorithms that independently process imaging data, calculate tumor position, assess localization confidence, and adjust treatment margins without requiring manual intervention. This self-service capability reduces the operational complexity burden on clinicians and staff, allowing sophisticated real-time adaptation to function with minimal human oversight.
3Device complexity
If static treatment margins are used, then treatment planning and delivery are simpler, but healthy tissue dose increases due to over-compensation for tumor motion
Solution Approach 1:
By implementing dynamic margin adaptation that responds to real-time tumor position and localization confidence, the system avoids the need to use uniformly large static margins throughout treatment. This dynamic approach allows margins to be minimized when tumor position is well-known and maximized only when uncertainty is high, thereby reducing unnecessary radiation exposure to healthy tissues while maintaining process simplicity through automated control.
Solution Approach 2:
The system continuously changes the margin parameter based on real-time imaging data and localization confidence metrics. This parameter adaptation enables the treatment system to optimize the balance between tumor coverage and healthy tissue sparing dynamically, reducing healthy tissue dose by adjusting margins according to actual conditions rather than relying on conservative fixed values.
Data Source
AI summary
Systems and methods directed to real-time treatment margin adaptation based on in-treatment imaging are provided. The system and method may utilize the potential of motion mitigation techniques such as couch tracking, DMLC, beam tracking, and the like to freeze tumor motion within the treatment aperture. A standard internal target volume (ITV) based margin plan and a minimum margin plan is created for the patient. The minimum margin plan assumes frozen intrafractional tumor motion. Depending on tumor location confidence in the motion mitigation technique, MLC leaf positions can be interpolated between the two plans to adjust margins during treatment delivery. If motion mitigation fails, the plan can be disabled resulting in the delivery of the current clinical standard of care. Dynamic aperture tracking may be employed with an electronic portal imaging device as the in-treatment imaging modality.