Scintillating Screen Detector for Charged Particle Dosimetry
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Solution Overview
Problem
Current detectors for quality assurance in charged particle therapy lack sufficient spatial resolution and dosimetric accuracy to accurately measure the delivered dose as a function of depth, leading to incomplete confidence in matching the delivered beam with the treatment plan.
Innovation Solution
A detector system comprising a scintillating screen with a mixture of scintillators emitting different spectra, combined with high-resolution imaging sensors and variable optics, to produce an output proportional to the dose deposited as a function of depth within a tissue phantom, enhancing spatial resolution and dosimetric accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single scintillator material is used in the detector, then the device complexity is reduced, but the dosimetric accuracy and spatial resolution are insufficient to accurately measure dose as a function of depth
Solution Approach 1:
The patent employs a composite scintillator screen containing multiple scintillator materials with different light emission spectra. Each scintillator material responds differently to charged particles at various depths, enabling the detector to accurately measure dose as a function of depth while maintaining a relatively simple overall detector structure. The composite nature allows differentiation of depth information through spectral analysis without requiring complex detector architecture.
Solution Approach 2:
The patent adds a spectral dimension to the detection by using multiple scintillator materials that emit at different wavelengths. This spectral dimension allows the detector to encode depth information in the light spectrum, transforming a one-dimensional depth measurement problem into a multi-dimensional measurement that can be resolved through spectral analysis of the combined scintillator output.
2Measurement precision
If high-resolution imaging sensors and variable optics are added to improve spatial resolution, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent designs the optical system with variable optics that can dynamically adjust their properties to serve multiple functions: optimizing spatial resolution for different measurement conditions, adapting to different scintillator spectral outputs, and potentially varying focal lengths or apertures based on the specific measurement requirements. This multi-functionality reduces the need for multiple specialized optical components.
Solution Approach 2:
The patent incorporates variable optics that can dynamically change their optical properties during operation. This dynamic capability allows the system to optimize spatial resolution adaptively based on measurement conditions, particle energy, and depth of interest, rather than requiring a fixed, over-engineered optical system for all possible conditions.
3Measurement precision
If a mixture of scintillators with different spectra is used, then dosimetric accuracy improves, but the difficulty of detecting and measuring increases
Solution Approach 1:
The patent exploits the different light emission spectra (colors) of multiple scintillator materials as a measurement dimension. Each scintillator material emits characteristic wavelengths of light when excited by charged particles, and the relative intensities of these different colors provide information about particle energy and depth. This color-based encoding simplifies the measurement task by transforming complex dosimetric information into spectral intensity ratios that can be measured with standard photodetectors.
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
The system provides improved spatial resolution and dosimetric accuracy, enabling more precise validation of treatment plans and ensuring the delivered dose matches the intended radiation distribution within the patient.
Implementation Method 1
a scintillating screen with a mixture of scintillators emitting different spectra
Data Source
AI summary
An apparatus and method are provided for performing Quality Assurance of complex beams of penetrating radiation inside a patient. A detector with a transverse scintillating screen images the radiation inside a tissue phantom with high spatial resolution. The scintillator is comprised of a mixture of two or more scintillators emitting different spectra of light and having different characteristic responses as a function of the beam LET value. The optics relaying the scintillation output have variable transmission with wavelength, further shaping the spectrum of light transmitted to the imaging sensor which also has spectrally varying sensitivity. Parameters of the scintillator construction, the optics, and the imaging sensor are chosen so the output of the composite detector is proportional to a characteristic of the input beam, for example the dose deposited as a function of depth inside the tissue phantom.