Optical Tracking System for Radiation Therapy Alignment
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Solution Overview
Problem
Current radiation therapy systems face challenges in accurately aligning radiation beams due to obstacles and patient movement, leading to inefficiencies and inaccuracies in delivering radiation doses, particularly in cases with contoured anatomy or steep skin slopes, where traditional optical distance indicators (ODIs) are impractical and time-consuming.
Innovation Solution
A system incorporating optically trackable bodies and a target alignment analyzing computer that uses passive retro-reflective indicators and a camera subsystem to determine precise source-to-surface distances and patient thicknesses without requiring individual calibration or repositioning, enabling efficient and accurate alignment of radiation beams on complex patient surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional optical distance indicators (ODIs) are used to measure source-to-surface distances, then measurement capability is provided, but the process becomes time-consuming and impractical for contoured anatomy or steep skin slopes
Solution Approach 1:
The patent replaces the mechanical ODI system with an optical tracking system using passive retro-reflective indicators and a camera subsystem. This substitution eliminates the need for manual positioning and reading of mechanical scales, enabling automated optical measurement of patient surface positions and calculation of source-to-surface distances, thereby reducing setup time while maintaining measurement precision
Solution Approach 2:
The patent creates an optical copy of the measurement system by using retro-reflective indicators that reflect camera light back to the camera, allowing non-contact measurement of patient surface positions. This optical copying approach enables measurement of contoured anatomy without physical contact or manual intervention, significantly reducing setup time compared to traditional mechanical ODIs
2Measurement precision
If traditional ODIs are used for measurement, then distance measurement is possible, but individual calibration and repositioning are required
Solution Approach 1:
The retro-reflective indicators automatically reflect camera light back to the camera without requiring external illumination or active power sources. The system self-calibrates by detecting the known positions of multiple indicators on the patient surface and automatically calculating source-to-surface distances, eliminating the need for manual calibration and repositioning operations
Solution Approach 2:
The passive retro-reflective indicators serve multiple functions simultaneously: they provide positioning references, enable optical tracking, and facilitate automatic distance calculation. This multi-functionality eliminates the need for separate calibration procedures and repositioning operations required by traditional ODIs, reducing device complexity while maintaining measurement accuracy
3Productivity
If radiation beams are delivered without accurate alignment verification, then treatment delivery is faster, but alignment accuracy and treatment precision deteriorate
Solution Approach 1:
The camera subsystem continuously tracks the positions of retro-reflective indicators on the patient surface and provides real-time feedback on alignment status. The system automatically calculates source-to-surface distances and compares them against treatment plan specifications, enabling rapid verification of target alignment without compromising accuracy while maintaining fast treatment delivery speed
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 solution significantly reduces the time and error associated with radiation therapy setup, allowing for precise and efficient delivery of radiation doses to targeted areas, even on contoured or obstructed surfaces, by providing real-time alignment data and streamlining the measurement process.
Implementation Method 1
uses passive retro-reflective indicators and a camera subsystem to determine precise source-to-surface distances
Data Source
AI summary
A system, tracker, program product, and methods to facilitate and verify proper target alignment for radiation delivery are provided. The system includes a radiation delivery apparatus having a radiation emitter, a rotating assembly controlled by a controller, and an application computer which provides treatment delivery instructions to the controller. The system also includes a trackable body having a trackable body reference point to be positioned adjacent a surface point of a patient to determine a position of such surface point. The system also includes an apparatus to track a trackable body which has a trackable body detector to detect a position of indicators carried by the trackable body and a trackable body determiner to determine a position of the trackable body reference point. The system also includes a target alignment analyzing computer having memory and target alignment analyzing program product stored therein to aid a user of the system to make and display various patient body-surface related measurements.