LINAC Isocenter Determination via Optical Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for determining the isocenter of a medical linear accelerator (LINAC) are inaccurate due to the difficulty in decoupling radiation steering issues from mechanical rotation issues, leading to potential errors in radiation delivery and adverse side effects.
Innovation Solution
A system that tracks the translation-rotation of mechanical components using a Signal Emitter Module with stereoscopic cameras to compute the axis of rotation of the Gantry, Collimator, and Table, providing real-time tracking and precise determination of the isocenter by aligning the internal coordinate system with the Earth's gravity direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radiation transmission images are used to determine axes of rotation, then isocenter determination can be performed, but radiation steering issues cannot be decoupled from mechanical rotation issues resulting in reduced accuracy
Solution Approach 1:
The measurement system is segmented into separate functional components: optical markers attached to mechanical components, cameras for optical detection, and computational processing. This separation allows independent measurement of mechanical rotation without radiation interference, resolving the coupling problem while maintaining measurement precision.
Solution Approach 2:
Optical markers serve as intermediaries between the mechanical rotation components and the detection system. These markers translate mechanical positions into optical signals that can be tracked by cameras, enabling accurate mechanical measurement without direct radiation involvement and thus decoupling the measurement systems.
2Manufacturing precision
If mechanical components rotate through non-concentric paths due to mechanical errors, then radiation beam precision is blurred, but traditional methods cannot accurately measure the magnitude of non-concentricity
Solution Approach 1:
The system continuously tracks the positions of optical markers attached to rotating components and provides feedback data about actual rotation paths. This feedback enables precise measurement of non-concentricity deviations from ideal circular paths, allowing quantification and correction of mechanical errors that affect radiation beam precision.
Solution Approach 2:
The mechanical measurement approach is replaced with an optical measurement system using cameras and optical markers. This substitution enables non-contact, high-precision tracking of mechanical component positions, accurately measuring non-concentric rotation paths without the limitations of traditional mechanical measurement methods.
3Measurement precision
If all three rotation axes (Gantry, Collimator, Table) are required to intersect at a single isocenter point, then treatment accuracy is maximized, but mechanical errors cause non-coincidence of axes requiring suboptimal isocenter selection
Solution Approach 1:
Optical markers and cameras serve as intermediaries to precisely measure the actual positions and orientations of all three rotation axes. This accurate measurement enables identification of the optimal isocenter point that minimizes deviations from perfect axis coincidence, improving treatment accuracy despite mechanical errors causing non-coincidence.
Solution Approach 2:
The optical tracking system serves multiple functions: it measures the positions of all three rotation axes (Gantry, Collimator, Table), tracks their movements during rotation, and provides data for computing the optimal isocenter. This multi-functional measurement system comprehensively addresses axis coincidence issues across all rotational components.
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 system achieves high precision in determining the isocenter, reducing radiation delivery errors and improving treatment accuracy by providing real-time mechanical movement tracking and alignment with the Earth's gravity, thus minimizing the impact of mechanical errors and non-concentric rotations.
Implementation Method 1
A Signal Emitter Module with stereoscopic cameras is attached to the LINAC gantry and the tracking markers are monitored by the Signal Receiver Module
Data Source
AI summary
A system to determine the isocenter of a LINAC includes apparatus and processes to determine the axis of rotation for the collimator, the gantry and the patient couch. The system and apparatus enable the tracking of the translation-rotation of mechanical components attached to the LINAC to compute the axis of rotation of Gantry, Collimator and Table. Based on the data collected related to these axis's the LINAC isocenter is determined. The apparatus utilized in the system includes a single emitter module, a signal receiver module, a positioning module. The system also includes a isocenter target module and a gravity module to determine a gravity vector for the LINAC.