Slit Collimator for Prompt Gamma Detection in Hadron Therapy
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Solution Overview
Problem
Current detection systems for charged hadron therapy, such as those using prompt gamma measurements, face challenges in achieving precise, real-time measurement of beam range due to mechanical complexity and trade-offs between spatial resolution and collimation, limiting their effectiveness for on-line verification during beam delivery.
Innovation Solution
A detection system featuring a collimator with a single slit-shaped portion and a scintillator array, configured to detect prompt gammas emitted from a larger portion of the beam line than the slit width, allowing for a one-dimensional view of the dose distribution without moving the detector, using a collimator material like tungsten and scintillator materials like LYSO, and employing photon counting devices for accurate beam range estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a multilayered collimator system with single slit is used to detect prompt gamma at 90°, then collimation is improved, but the device cannot obtain prompt gamma distribution along the beam direction without moving the detector
Solution Approach 1:
The patent transitions from detecting prompt gamma at a single angle (90°) to detecting along the beam direction by orienting the slit parallel to the beam axis. This dimensional change in detection geometry allows the collimator to capture prompt gamma distribution along the beam path without requiring detector movement, resolving the contradiction between collimation precision and device complexity.
Solution Approach 2:
The patent makes the detection system adaptable by allowing the slit orientation to be parallel to the beam axis rather than perpendicular, enabling dynamic adjustment of the detection geometry to match the beam direction. This eliminates the need for mechanical movement while maintaining collimation effectiveness.
2Measurement precision
If a linear array of scintillation detectors with collimator slits is used for online measurement, then spatial resolution is improved, but the shielding becomes mechanically complicated
Solution Approach 1:
The patent extracts the essential collimation function to a single slit structure oriented parallel to the beam axis, removing the complex multilayered collimator system. This simplified slit design maintains spatial resolution capability while eliminating mechanical complexity, as the slit geometry alone provides sufficient collimation for online measurement.
Solution Approach 2:
The patent changes the orientation parameter of the slit from perpendicular to parallel with respect to the beam axis. This parameter change transforms the collimator from a complex multilayered structure into a simple single-slit design that achieves the same spatial resolution function without mechanical complexity.
3Device complexity
If a pin-hole camera is used with scintillator and photodetector array, then detector movement is eliminated, but the number of detectable prompt gammas is reduced
Solution Approach 1:
The patent changes the detection geometry from a pin-hole camera configuration to a slit-based collimator with the slit parallel to the beam axis. This dimensional change opens up a larger solid angle for prompt gamma detection along the beam direction, increasing the number of detectable prompt gammas while maintaining the advantage of eliminating detector movement.
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 configuration enables precise, real-time estimation of the beam range with improved spatial resolution and collimation, allowing for accurate placement of the Bragg peak and minimizing tissue damage, with the ability to detect shifts in the beam range with high accuracy.
Implementation Method 1
a collimator formed of a first material and provided with a single slit-shaped portion which comprises a material of a lower thickness and/or density than said first material, said slit-shaped portion being configured to be arranged perpendicularly to the beam line and facing the target
Implementation Method 2
a detection means suitable for detecting said prompt gammas
Implementation Method 3
at least one array of photon counting devices associated with said scintillator
Data Source
Figure 1a~1c
Figure 1d~2a
Figure 2b~2c
AI summary
The invention is related to an apparatus and method for charged hadron therapy verification by detecting and/or quantifying prompt gammas produced when irradiating a target (6) with a charged hadron beam. The apparatus comprises a collimator (1) provided with a slit-shaped portion (2) configured to be arranged perpendicularly to the beam line and facing the target, a detection means (3,4) suitable for detecting said prompt gammas and a calculation and representation means. In the apparatus and method of the invention, the slit is configured to allow the passage of prompt gammas emitted from a range of depths in said target (6), said depths being measured in the direction of the charged hadron beam. Furthermore, said detection means is configured to detect prompt gammas emitted from each location within said range, and said calculation and representation means is configured to derive from a detected prompt gamma a value representative of the dose at the location from where said prompt gamma is emitted, and to represent a dose-related distribution for a plurality of locations within said range.