LINAC Beam Alignment via Imaging Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current radiation therapy systems face challenges in accurately aligning radiation beams due to mechanical errors during gantry rotation, leading to blurring of the radiation field and suboptimal treatment delivery.
Innovation Solution
A method and apparatus for determining and adjusting beam alignment parameters of a medical linear accelerator (LINAC) using imaging devices to acquire radiation transmission images, calculate target-to-beam-axis distances, and optimize beam alignment by modeling the dependence of these distances on beam alignment parameters, thereby ensuring precise alignment regardless of gantry rotation errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical gantry rotation is used to deliver radiation beams, then treatment delivery is enabled, but mechanical errors cause beam misalignment and field blurring
Solution Approach 1:
The patent replaces mechanical alignment methods with a computational approach. Instead of relying solely on mechanical precision of the gantry rotation, the system uses imaging devices to capture radiation transmission images and computational algorithms to determine optimal beam alignment parameters that compensate for mechanical errors, thereby substituting mechanical precision requirements with computational correction
Solution Approach 2:
The patent implements a feedback mechanism where radiation transmission images are acquired during gantry rotation, beam axis locations are determined from these images, and the alignment parameters are optimized based on the measured deviations. This closed-loop feedback system continuously corrects for mechanical errors in real-time during treatment delivery
2Measurement precision
If beam alignment parameters are adjusted to compensate for gantry rotation errors, then alignment precision is improved, but additional measurement and calculation steps are required
Solution Approach 1:
The patent makes the imaging device serve multiple functions: it is used both for treatment verification and for beam alignment measurement. The same radiation transmission imaging capability is leveraged to determine beam axis locations and optimize alignment parameters, eliminating the need for separate alignment measurement equipment and reducing overall system complexity
Solution Approach 2:
The system uses its own imaging and radiation delivery capabilities to perform self-alignment. The LINAC uses its imaging device to measure its own beam alignment, and the computational system determines optimal parameters based on self-measured data, making the alignment process self-contained and reducing external complexity
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 approach enables precise alignment of radiation beams, minimizing mechanical errors and ensuring accurate delivery of radiation therapy, even during gantry rotation, thereby improving treatment efficacy and patient outcomes.
Implementation Method 1
using an imaging device of the LINAC to acquire a radiation transmission image indicative of a radiation field of the radiation beam after passing by a radiation opaque marker
Implementation Method 2
The angle that the radiation beam 210 exits the collimator 104, relative to the radiation beam 210 before traveling through the bending magnet 204, is the beam bending angle 208. The beam bending angle 208 can be modified by altering the amount of current applied to the bending magnet 204.
Data Source
AI summary
Radiation beam alignment for a LINAC including (1) for each beam alignment parameter value of a set: (a) with a beam alignment parameter of a LINAC set to the beam alignment parameter value, using a gantry to generate a radiation beam; (b) using an imaging device to acquire a radiation transmission image indicative of a radiation field of the radiation beam after passing by a radiation opaque marker; (c) determining a location of a beam axis of the radiation beam and a center of a shadow of the marker based on the radiation transmission image; and (d) determining a target-to-beam-axis distance between the location of the beam axis and the center of the shadow of the radiation opaque marker; and (2) determining an optimum beam alignment parameter value based on the beam alignment parameter values and the target-to-beam-axis distances determined with the LINAC set to the beam alignment parameter values.