Prompt Gamma Timing for Particle Beam Depth Verification
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Solution Overview
Problem
Existing prompt gamma cameras for measuring particle beam penetration depth are heavy, have poor detection efficiency, and are sensitive to target position and anatomy, requiring complex collimators and calibration libraries.
Innovation Solution
A particle beam system with a timing controller and two gamma detectors positioned at different angles relative to the beam direction, measuring prompt gammas in synchrony with a timing reference signal to determine penetration depth based on photon travel shift, independent of target structure, using a data analyser to calculate penetration depth from timing profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If collimator cameras are used to measure prompt gammas, then penetration depth can be determined, but the device becomes heavy and detection efficiency becomes poor
Solution Approach 1:
The patent removes the collimator component from the gamma camera system. By detecting prompt gammas without collimators and using time-of-flight information instead, the system eliminates the heavy collimator structure while maintaining penetration depth measurement capability through a different physical approach
Solution Approach 2:
The patent replaces the mechanical collimator system with a time-based detection method. Instead of using physical collimator structures to define gamma ray paths, the system uses timing information and positional detection to determine penetration depth, substituting mechanical components with temporal measurement techniques
2Measurement precision
If collimator cameras are used to measure prompt gammas, then penetration depth can be determined, but detection efficiency becomes poor
Solution Approach 1:
By removing the collimator, the system eliminates the component that blocked most gamma rays. The open detection geometry allows much higher gamma ray detection efficiency while still achieving accurate penetration depth measurement through time-of-flight and positional information
Solution Approach 2:
The patent changes the measurement parameter from spatial filtering (collimator geometry) to temporal measurement (time-of-flight). This parameter change allows the system to maintain measurement precision while dramatically improving detection efficiency by accepting gamma rays from all directions and using timing information for depth determination
3Measurement precision
If collimator cameras are used, then penetration depth measurement is possible, but the system becomes sensitive to target position and anatomy requiring complex calibration
Solution Approach 1:
The patent uses timing information as feedback to determine penetration depth. By measuring the time-of-flight of prompt gammas and correlating it with particle energy loss, the system obtains depth information that is independent of target position and anatomy, eliminating the need for complex calibration libraries
Solution Approach 2:
The system replaces the complex calibration and positioning system with a time-based measurement approach. Instead of requiring precise knowledge of target position and anatomy through calibration libraries, the system uses temporal measurement of prompt gamma emission to directly determine penetration depth
4Measurement precision
If prompt gamma profiles are measured with collimator cameras, then penetration depth variation can be deduced, but the measurements are sensitive to target position and anatomy
Solution Approach 1:
The system uses time-of-flight information as feedback to determine penetration depth. This temporal measurement provides reliable depth information that is independent of target position and anatomy, making the measurement robust against variations in target structure
Solution Approach 2:
The patent changes from measuring spatial gamma distribution (which is sensitive to target structure) to measuring temporal gamma emission characteristics. This parameter change makes penetration depth determination robust against target position and anatomy variations
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
Improves signal-to-noise ratio and provides a robust, simplified method for determining particle beam penetration depth, unaffected by target inhomogeneities or structure, enhancing detection sensitivity and reducing complexity.
Implementation Method 1
A time of flight signal (TOF) can be determined using the first detector as a start signal and the second detector as a stop signal. It is suggested to correlate this TOF signal with the penetration depth of the particle beam.
Implementation Method 2
prompt gammas are measured with a camera that is using one or more collimators... there exists a known correlation between the emission of prompt gammas and the penetration depth of the particle beam in a target
Data Source
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AI summary
The invention is related to a particle beam system for delivering particles or bunches of particles to a target whereby the system is comprising detectors for detecting prompt gammas. Prompt gammas are detected at two different locations with respect to the target and in synchrony with a reference timing signal so as to obtain prompt gamma timing profiles. The difference in time width of the two timing profiles is used to deduce a penetration depth of the particle beam in the target. The invention is also related to a method for verifying a penetration depth of an energetic particle beam by correlating the difference of the two prompt gamma timing profiles with the difference in location of the detectors with respect to the target.