Modular Multilayer Ionization Chamber for Proton Beam Calibration

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Solution Overview

Problem

Current calibration methods for charged particle beams in external radiotherapy, such as protons and carbon ions, are time-consuming and costly due to the need for multiple instruments and instruments with a fixed number of channels, which are not fully utilized in all healthcare centers, limiting the efficiency of QA procedures.

Innovation Solution

A modular multilayer ionization chamber calibration apparatus with interchangeable sensor modules that can be configured according to the center's needs, allowing for instantaneous evaluation of beam characteristics in three directions and enabling simultaneous reading of various ionization chamber types for comprehensive beam calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple fixed-channel instruments are used for beam calibration, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvebeam calibration precisionVSAvoidnumber of instruments
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple ionization chambers with different channel configurations into a single modular apparatus. Different sensor modules (e.g., 32-channel, 64-channel, 128-channel modules) can be integrated together or used separately, allowing the system to function as multiple instruments in one device, thereby reducing overall device complexity while maintaining measurement precision.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The apparatus is designed with universal modularity, where a single device can perform multiple calibration functions by swapping or combining different sensor modules. Each module can handle different beam energies and clinical requirements, making the apparatus universally applicable for various beam calibration scenarios without needing separate specialized instruments.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If small ionization chambers move through dummy materials for calibration, then measurement precision is improved, but loss of time increases

Engineering Contradiction:
Improvedepth-dose curve accuracyVSAvoidQA procedure duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The ionization chamber is segmented into multiple layers (e.g., 32, 64, or 128 independent measurement layers) stacked along the beam direction. This segmentation allows simultaneous measurement of depth-dose characteristics at multiple depths within a single beam irradiation, eliminating the need to physically move the chamber through dummy materials and dramatically reducing calibration time while maintaining measurement precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stacked multilayer structure enables continuous measurement of the entire depth-dose curve in a single static position during beam irradiation. All layers record data simultaneously and continuously, providing complete depth-dose information without interruption or movement, thereby maintaining precision while eliminating time loss associated with sequential measurements.

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If high-energy beams (>220 MeV) are used to fully utilize fixed-channel sensors, then productivity is improved, but adaptability decreases

Engineering Contradiction:
Improvecalibration throughputVSAvoidenergy range compatibility
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The apparatus employs dynamic modularity, allowing the system configuration to adapt to different clinical needs. Users can select and combine sensor modules with different channel counts (32, 64, 128 channels) depending on the beam energy and treatment requirements. This dynamic reconfigurability enables full utilization of sensor channels across a wide energy range (70-250 MeV), maintaining productivity while significantly improving adaptability to different energy levels.

Inventive Principle:
Principle #15Dynamics

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 solution reduces calibration time and costs by allowing flexible configuration and simultaneous evaluation of beam characteristics, increasing the efficiency of QA procedures and enabling more patients to be treated in healthcare centers.

Implementation Method 1

The interaction of proton and ion beams with human tissue (which is mainly made up of water) enables the majority of the dose to be conveyed to a precise depth

Methodology Applied
Scientific EffectIonization: Ionisation

Data Source

PatentEP3295215B1Apparatus for the calibration of beams of charged particles for external radiotherapy, in particular beams of protons, carbon ions, and other ion species, emitted by particle accelerators, and corresponding calibration method
Publication Date: 2021.12.01 DE TEC TOR SRL
  • EP3295215B1 patent drawingFigure 1
  • EP3295215B1 patent drawingFigure 2
  • EP3295215B1 patent drawingFigure 3

AI summary

An apparatus for the calibration of beams of charged particles (1300), in particular protons, carbon ions, and other ion species, emitted by systems for external radiotherapy with charged particles, comprising at least one sensor including multilayer ionization chambers (10), which comprises a plurality of sensor channels (20). According to the invention, said apparatus (100) includes a plurality of modular elements (120), each comprising a supporting frame (130), which identifies a seat (132) configured for housing a sensor with multilayer ionization chambers (10) or a sensor (30) with ionization chamber, which is able to supply information on the two-dimensional profile of the beam of charged particles (1300), said modular elements (120) being configured for being assembled to form a stack (115) in the direction (Z) of propagation of a beam of charged particles (1300) by aligning said seats (132) in the direction of said beam of charged particles (1300).