Charged Particle Therapy Detector for Real-Time Range Verification
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Solution Overview
Problem
Existing charged particle therapy (CPT) systems face significant uncertainties in particle range due to tissue heterogeneities and anatomical changes, leading to increased treatment margins and limited beam irradiation angles, which hinder the full exploitation of particle range, especially near critical organs and with organ motion.
Innovation Solution
A system utilizing an on-line detector with optically segmented organic scintillators and SiPMs for real-time detection of secondary neutrons and prompt gamma-rays, enabling full kinematic reconstruction of their angles and energies, and a processing unit for precise dose verification and image guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If safety margins are increased around the tumour to account for range uncertainties, then the reliability of dose delivery is improved, but the volume of healthy tissue exposed to radiation increases
Solution Approach 1:
The patent implements real-time range verification using prompt gamma-ray detection to provide feedback on the actual particle range during treatment. This feedback mechanism allows dynamic adjustment of treatment parameters to maintain dose delivery reliability without requiring excessive safety margins, thereby reducing radiation exposure to healthy tissue.
Solution Approach 2:
The system changes the measurement parameter from indirect anatomical imaging to direct prompt gamma-ray detection, which provides real-time information about the actual particle range. This parameter change enables precise control of treatment margins based on actual physical range rather than statistical estimates, reducing healthy tissue exposure while maintaining reliability.
2Measurement precision
If detection systems are made more precise to achieve sub-millimeter range verification, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent extracts and detects only the specific prompt gamma-rays produced at the Bragg peak through their characteristic 2.2 MeV neutron capture signature. By focusing on this specific signal rather than attempting to detect all radiation types, the system achieves sub-millimeter precision while managing device complexity through selective detection.
Solution Approach 2:
The system uses secondary neutrons as an intermediary to indirectly detect the prompt gamma-ray position. The neutrons are produced by prompt gamma-ray interactions, and their detection provides information about the original gamma-ray position and energy, enabling precise range verification through a manageable detection process.
3Ease of operation
If the detector size is reduced to increase system flexibility, then the ease of operation is improved, but the detection efficiency may be compromised
Solution Approach 1:
The patent applies local quality by concentrating detection resources on the specific region and energy range where prompt gamma-rays are produced (at the Bragg peak). The detector is optimized to detect neutrons in the specific energy range produced by 2.2 MeV gamma-ray capture, achieving high detection efficiency with a compact detector positioned strategically near the treatment target.
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
Achieves sub-millimeter precision in real-time range verification and dose delivery verification with reduced system size and increased flexibility, improving the efficiency of CPT by up to a magnitude compared to prior art.
Implementation Method 1
for detection of secondary neutrons, the detector is configured to produce at least two consecutive elastic scatters on hydrogen-1 nuclei, i.e. (n,p) scatters, in the sensitive volume of the detector
Implementation Method 2
The detector comprises a scintillator, comprising an array of optically segmented organic scintillator elements
Implementation Method 3
for detection of secondary prompt gamma-rays, the detector is configured to produce at least two consecutive incoherent prompt gamma-ray scatters followed by a third scatter of any kind in the sensitive volume of the detector
Implementation Method 4
The detector comprises a scintillator, comprising an array of optically segmented organic scintillator elements
Implementation Method 5
optically segmented organic scintillators and SiPMs for real-time detection
Data Source
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Figure 2A~2C
Figure 3A~3C
AI summary
A system for charged particle therapy verification, comprising a first detector configured for detection of secondary particles emitted from a target irradiated with a charged particle beam, wherein the detector is configured to cause at least two consecutive elastic scatters in the detector for secondary particles of fast neutrons and two consecutive incoherent scatters followed by a third scatter, being one of: photoelectric effect, incoherent scatter or pair production for secondary particles of prompt gamma-ray types.