Radiotherapy Delivery Verification With Opposed Radiation Imaging
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Solution Overview
Problem
Existing radiotherapy systems face challenges in confirming whether the emitted radiation during a treatment session aligns with the planned dose, due to absorption, scattering, and component errors, which can lead to inaccurate measurements and potential irradiation of healthy tissue.
Innovation Solution
Methods are developed to verify the delivery of therapeutic radiation using imaging data from a radiation imager, monitoring the position and functionality of beam-shaping components like the multi-leaf collimator, and generating notifications for deviations from the planned radiation, including graphical representations and dose maps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radiation measurements are taken using a radiation detector, then radiation dose delivery can be monitored, but measurement accuracy deteriorates due to absorption and scattering of radiation
Solution Approach 1:
The patent introduces an intermediary verification system that uses radiation detectors positioned at multiple locations around the treatment area to indirectly verify radiation delivery accuracy. Instead of relying on a single detector that suffers from absorption and scattering, the system uses multiple detectors to capture radiation from different angles and paths, allowing for cross-validation and more accurate determination of actual radiation delivery through computational analysis.
Solution Approach 2:
The system implements real-time feedback by continuously monitoring radiation measurements from multiple detectors during treatment delivery and comparing actual delivery against the treatment plan. When discrepancies are detected, the system can alert operators or even automatically adjust delivery parameters to correct deviations, ensuring measurement accuracy despite absorption and scattering effects.
2Reliability
If radiation delivery is monitored in real-time, then patient safety is improved, but system complexity increases due to additional verification components
Solution Approach 1:
The verification system is designed to be integrated with the existing radiotherapy delivery system, using the same radiation source and treatment positioning infrastructure. The radiation detectors used for verification serve dual purposes: they monitor treatment delivery accuracy while also providing information that can be used for treatment planning validation and quality assurance, reducing the need for entirely separate verification equipment.
Solution Approach 2:
The system uses the treatment delivery process itself to generate verification data. The radiation photons used to treat the patient are the same photons detected by the verification detectors, eliminating the need for separate test beams or additional radiation sources. The system self-verified by utilizing the therapeutic radiation beam for both treatment and monitoring purposes.
3Manufacturing precision
If beam-shaping components are precisely positioned, then radiation delivery accuracy is improved, but component manufacturing and positioning complexity increases
Solution Approach 1:
The patent replaces reliance on purely mechanical positioning precision with an optical/electronic verification system. Instead of depending solely on the mechanical accuracy of beam-shaping component positioning, the system uses radiation detectors to optically/electronically verify the actual position and function of these components during treatment, compensating for manufacturing tolerances and positioning errors through measurement and feedback.
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
Ensures accurate delivery of radiation to the target region, reducing the risk of healthy tissue irradiation by providing real-time verification and ensuring compliance with treatment plans.
Implementation Method 1
a radiation detector (which may also be referred to as a radiation imager) located opposite the therapeutic radiation source to take measurements of the radiation emitted by the therapeutic radiation source
Implementation Method 2
The beam-shaping components (e.g., jaws, collimators) may have movable radiation-blocking elements that can be adjusted to focus and shape the radiation beam to target the tumor and avoid surrounding anatomy
Data Source
AI summary
Disclosed herein are methods for verifying whether a radiotherapy delivery system is delivering therapeutic radiation to the target region in accordance with instructions from the radiotherapy system controller. The methods utilize imaging data acquired by a radiation imager (e.g., MV detector) that is located across from (e.g., opposite) the therapeutic radiation source. In some variations, the imaging data from the radiation imager is used to determine whether the components of the radiation beam-shaping assembly are in the location specified by the controller instructions. Also disclosed herein are methods for verifying whether the radiation beams emitted by the therapeutic radiation source intersect with a target region and/or a contour around the target region, including methods for determining delivered fluence and dose estimates.