Linear Accelerator Imaging Mode Beam Optimization
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Solution Overview
Problem
Conventional imaging systems in linear accelerators are ineffective and inefficient for determining patient positioning during radiation treatment, as they deliver a radiation beam with characteristics unsuitable for imaging, leading to potential misdelivery of radiation doses and increased errors in positioning.
Innovation Solution
A system that automatically adjusts the focal spot size, moves a flattening filter, replaces targets, and positions a scatter-reducing filter within the radiation beam path in response to instructions to enter imaging or treatment modes, optimizing beam characteristics for either imaging or treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a radiation beam is generated by a linear accelerator for imaging, then the beam can be used to determine patient position, but the beam delivers a dose rate that is significantly less than for treatment and other characteristics are unsuitable for imaging
Solution Approach 1:
The system dynamically adjusts beam characteristics by moving components (flattening filter, scatter-reducing filter, targets) between different positions based on whether imaging or treatment mode is active. This allows the same linear accelerator to optimize its radiation beam for either imaging quality or high dose rate treatment requirements
Solution Approach 2:
The system changes physical parameters of the radiation beam by adjusting focal spot size, filter positions, and target configurations. These parameter changes enable the beam to achieve suitable characteristics for imaging while maintaining the capability for high dose rate treatment
2Measurement precision
If conventional imaging systems are used to determine patient position, then the system can generate portal images, but the system is ineffective and inefficient for determining patient positioning during radiation treatment
Solution Approach 1:
The linear accelerator is configured to perform multiple functions: it can generate radiation beams optimized for imaging (with specific filter positions and focal spot sizes) and for treatment (with different configurations). This multi-functionality allows the same device to provide both imaging capability and reliable treatment delivery
Solution Approach 2:
The system uses portal images generated during imaging mode to verify patient positioning before treatment. This feedback mechanism allows the system to detect positioning errors and correct them, ensuring accurate radiation delivery to the target area
3Measurement precision
If the focal spot size is reduced for imaging mode, then imaging quality is improved, but the beam characteristics become unsuitable for treatment
Solution Approach 1:
The focal spot size is dynamically adjusted based on the operating mode. During imaging mode, the focal spot size is reduced to improve image quality, while during treatment mode, the focal spot size is increased to provide appropriate beam characteristics for radiation delivery
Solution Approach 2:
The system segments the beam generation process into distinct imaging and treatment configurations by using separate targets and filter positions. This segmentation allows each mode to have optimized parameters without compromising the other
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
Enhances the accuracy of patient positioning by optimizing radiation beam characteristics for imaging and treatment, reducing errors and ensuring effective delivery of radiation doses to tumors while minimizing exposure to healthy tissue.
Implementation Method 1
A linear accelerator produces electrons or photons having particular energies
Implementation Method 2
destroy cells within the target area by causing ionizations within the cells or other radiation-induced cell damage
Implementation Method 3
moving a flattening filter out of a path of the radiation beam, replacing a first target for photon emission with a second target for photon emission, or moving a scatter-reducing filter into the path of the radiation beam
Data Source
AI summary
Some embodiments include reception of a first instruction to enter an imaging mode, and, in response to the first instruction, automatic performance of at least one of: reduction of a focal spot size of a radiation beam, movement of a flattening filter out of a path of the radiation beam, replacement of a first target for photon emission with a second target for photon emission, or movement of a scatter-reducing filter into the path of the radiation beam. Embodiments may further include reception of a second instruction to enter a first radiation treatment mode, and, in response to the second instruction, automatic performance at least one of: increase of a focal spot size of the radiation beam, movement of the flattening filter into the path of the radiation beam, replacement of the second target with the first target, or movement of the scatter-reducing filter out of the path of the radiation beam.