Hybrid 2D Detector Combining Ionization Chambers and Semiconductors
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Solution Overview
Problem
Existing radiation detectors for dosimetry in radiation therapy suffer from low spatial resolution and high energy dependence, particularly in regions with high linear energy transfer, limiting the accuracy and precision of dose maps.
Innovation Solution
A hybrid detector system comprising an ionization chamber detector and an additional detector, such as a semiconductor detector, aligned along the Z-axis, with an intelligence module to calculate doses based on measurements from both detectors, compensating for the drawbacks of each type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ionisation chambers are used for dosimetry measurements, then measurement accuracy is maintained, but spatial resolution deteriorates (marginal spatial resolution of the order of mm)
Solution Approach 1:
The patent combines two different detector types (ionisation chambers and semiconductor detectors) into a single hybrid detector system. The ionisation chambers provide accurate dose measurements while the semiconductor detectors provide high spatial resolution, and the combination allows both characteristics to be achieved simultaneously through data fusion processing.
Solution Approach 2:
The hybrid detector uses a composite structure combining different detection materials (gas-filled ionisation chambers and solid-state semiconductor detectors) arranged in alternating layers. This composite architecture allows each material to contribute its strengths: ionisation chambers for accuracy and semiconductor detectors for spatial resolution.
2Manufacturing precision
If semiconductor detectors are used to improve spatial resolution, then spatial resolution is improved (order of µm), but energy dependence increases (high energy dependence and quenching)
Solution Approach 1:
The ionisation chambers act as an intermediary reference system that provides accurate, energy-independent dose measurements. These measurements serve as a reference to correct and calibrate the semiconductor detector signals, compensating for the semiconductor detectors' energy dependence and quenching effects through comparative measurement and data processing.
Solution Approach 2:
The hybrid detector system uses feedback processing where the measurements from ionisation chambers are used to correct and refine the semiconductor detector readings. The system continuously compares and adjusts the semiconductor detector signals based on the reference measurements from ionisation chambers, thereby compensating for energy dependence variations.
3Manufacturing precision
If the distance between adjacent ionisation chambers is reduced to improve spatial resolution, then spatial resolution is improved, but signal-to-noise ratio deteriorates
Solution Approach 1:
The semiconductor detectors create a high-resolution copy of the dose distribution pattern at the same location as the ionisation chambers. This copy provides fine spatial detail without requiring the ionisation chambers themselves to be closely spaced, thereby maintaining adequate signal-to-noise ratios in the primary measurement system while achieving high spatial resolution through the copied data from semiconductor detectors.
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 hybrid detector system provides high accuracy, precision, and spatial resolution with reduced energy dependence, enabling reliable and high-resolution dosimetry for radiation therapy quality assurance.
Implementation Method 1
The fluid is ionized by the radiation (5) traversing the ionization chamber (ICi) forming charged ions
Implementation Method 2
In direct conversion detectors, the ionising radiation produces electron-hole pairs directly in the semiconductor
Implementation Method 3
Indirect conversion detectors include scintillating detectors, comprising a scintillation layer that converts the ionizing radiation into optical photons
Data Source
Figure 1a~1c
Figure 2a~2f
Figure 3a~5b
AI summary
The invention relates to a detector (1) for characterizing a dosimetry of a radiation, comprising, • an ionizing detector (1IC) configured for characterizing a dosimetry of a radiation beam (5) propagating along a Z-axis, the ionizing detector (1 IC) comprising a matrix of ionisation chambers (ICi) distributed over a plane (X,Y) normal to the Z-axis, wherein the ionizing detector has a first spatial resolution over the plane (X, Y), • an additional detector (1A) different from the ionizing detector (1IC) and having a second spatial resolution over the plane (X, Y) higher than the first spatial resolution over the plane (X, Y) of the ionizing detector and is positioned in series along the Z-axis relative to the ionizing detector (1IC), and • an intelligence (10) configured to calculate a distribution of calculated doses (Dij) from the doses (DICi) measured by the ionizing detector (1IC) and the doses (DAij, DA0j) measured by the additional detector (1A).