Ion PBS Spot Selection Method for Reducing Computation Time
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Solution Overview
Problem
Existing ion-based radiation treatment planning methods face challenges in efficiently selecting spots for treatment plans, leading to long computation and optimization times, especially for treatments involving multiple beams.
Innovation Solution
A computer-based method for selecting spots in ion beam radiation treatment plans involves defining positions for Bragg peak locations, performing ray tracing to determine potential spots, and selecting the best spots to cover the target while reducing redundancy and optimizing beam directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a large number of spots are used to cover the target with Bragg peaks, then target coverage is improved, but computation time and optimization time increase significantly
Solution Approach 1:
The patent combines multiple spots that have Bragg peaks at the same or nearly the same position into a single spot. This merging process reduces the total number of spots from potentially millions to a manageable number, thereby decreasing computation and optimization times while preserving the cumulative dose effect of the original multiple spots.
Solution Approach 2:
The patent extracts and eliminates redundant spots from the treatment plan. By identifying and removing spots with overlapping Bragg peak positions, the method retains only the essential spots needed for adequate target coverage, removing unnecessary computational overhead while maintaining therapeutic effectiveness.
2Reliability
If multiple beams are used for ion arc treatment, then treatment robustness is improved, but the number of spots with overlapping Bragg peaks increases
Solution Approach 1:
The patent systematically merges spots across multiple beams that converge at the same target position. By consolidating these overlapping spots into single representative spots, the method maintains the multi-beam robustness advantage while eliminating the exponential growth in spot complexity that would otherwise result from combining multiple beams.
3Ease of manufacture
If spots are selected before optimization with fixed beam directions, then setup simplicity is improved, but optimization efficiency deteriorates
Solution Approach 1:
The patent performs preliminary spot selection and merging before the optimization process, creating a reduced set of candidate spots. This preliminary action simplifies the subsequent optimization by providing a pre-processed, non-redundant spot set that requires less computational effort to optimize, thereby improving overall optimization efficiency without sacrificing setup simplicity.
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 method ensures effective target coverage while significantly reducing the number of spots and computation time, facilitating faster and more robust treatment plan optimization.
Implementation Method 1
for each position, for at least one beam direction, performing a ray trace to determine characteristics of a potential spot in the beam that will place its Bragg peak in the position
Implementation Method 2
The direction and energy therefore determine where the Bragg peak of this spot will be located within the patient, that is, where most of its energy will be deposited
Data Source
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AI summary
A computer-based method of providing a set of selected spots for use in ion radiotherapy optimization is proposed, the method comprising the steps of defining a number of positions in the volume, each position corresponding to a possible Bragg peak location, the positions being defined to provide coverage of the volume, for each position, for at least one beam direction, performing a ray trace to determine characteristics of a potential spot in the beam that will place its Bragg peak in the position and for each position, selecting zero, one or more of the potential spots, based on the characteristics, and including the one or more selected spots in the set of selected spots. The set of selected spots may be used in treatment planning. The invention also relates to computer program products and a computer system for performing the methods.