Hadron Beam Verification Apparatus Using Multi-Thickness Degraders

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Solution Overview

Problem

Current proton beam facilities using the Pencil Beam Scanning technique require lengthy verification routines, taking at least 60 minutes, which reduces treatment facility efficiency due to the need for separate measurement devices for various beam characteristics, and existing dosimetry devices are not suitable for measuring hadron beam range effectively.

Innovation Solution

An apparatus with a main degrader element and a multiple thickness degrader element, combined with a two-dimensional detection system, allows for the verification of beam range, spot size, and spot position without repositioning, using data points near the Bragg peak to estimate beam range with high resolution, reducing verification time to about 15 minutes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate measurement devices are used for various beam characteristics (beam range, spot position, spot size, deposited dose), then measurement accuracy is improved, but verification time increases to at least 60 minutes

Engineering Contradiction:
Improvebeam characteristic verification accuracyVSAvoidverification time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent combines multiple separate measurement devices into a single integrated verification apparatus. The apparatus includes a water-equivalent phantom with multiple degrader elements of different thicknesses and a 2D detector array that simultaneously measures beam range, spot position, spot size, and deposited dose in one verification routine, reducing verification time from 60+ minutes to approximately 15 minutes while maintaining measurement accuracy.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The verification apparatus is designed as a universal device that can perform multiple measurement functions simultaneously. The water-equivalent phantom with varying degrader thicknesses and the 2D detector system enable single-apparatus verification of beam range, spot position, spot size, and dose deposition, eliminating the need for separate specialized devices for each measurement type.

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

2Productivity

If a single verification apparatus is used for all beam characteristics, then verification efficiency is improved, but measurement precision for specific characteristics may be compromised

Engineering Contradiction:
Improveverification efficiencyVSAvoidbeam characteristic measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent merges multiple measurement capabilities into one apparatus without sacrificing precision. The water-equivalent phantom with precisely engineered degrader elements and the 2D detector array work together to provide accurate simultaneous measurements of beam range, spot position, spot size, and dose, maintaining the precision previously achieved only by separate specialized devices.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The phantom incorporates local variations in water-equivalent thickness through multiple degrader elements of different thicknesses positioned at specific locations. This local quality variation allows the single apparatus to accurately measure different beam characteristics at different depths and positions, maintaining measurement precision for each specific parameter while enabling simultaneous verification of all characteristics.

Inventive Principle:
Principle #3Local quality

3Device complexity

If existing dosimetry devices with fixed build-up plate thickness are used, then device simplicity is maintained, but beam range measurement capability is lost

Engineering Contradiction:
Improvedosimetry device structureVSAvoidbeam range measurement capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent segments the phantom into multiple distinct degrader elements, each with a specific water-equivalent thickness (e.g., 5mm, 10mm, 15mm, 20mm). This segmentation allows the apparatus to measure beam range at multiple different depths by selecting appropriate degrader elements, providing adaptability for various beam energies and ranges while maintaining a relatively simple overall device structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the key parameter of water-equivalent thickness by incorporating multiple degrader elements with different thicknesses. This parameter variation enables the single apparatus to adapt to different beam range measurement requirements, allowing verification of beam range for various hadron beam energies without requiring multiple specialized devices.

Inventive Principle:
Principle #35Parameter changes

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

Enables efficient verification of hadron beam characteristics within a shorter timeframe, improving treatment facility efficiency by allowing simultaneous measurement of beam range, spot size, and spot position, and estimating beam range with high accuracy.

Implementation Method 1

a main degrader element (1) for reducing said beam range of said pencil beam

Methodology Applied
Scientific EffectEnergy loss in matter: Absorption (EM radiation)

Implementation Method 2

a two-dimensional detection means (6), suitable for detecting a deposited dose or a signal representative thereof or proportional thereto

Methodology Applied
Scientific EffectIonization: Ionisation

Implementation Method 3

a scintillator screen equipped with a CCD camera

Methodology Applied
Scientific EffectScintillation: Scintillation

Implementation Method 4

a plurality of data points in the vicinity of a Bragg peak appearing when a beam having said beam energy passes through said main degrader element

Methodology Applied
Scientific EffectBragg peak: Bragg Diffraction

Data Source

PatentEP2841160B1Apparatus and method for hadron beam verification
Publication Date: 2018.04.11 ION BEAM APPL
  • EP2841160B1 patent drawingFigure 1a
  • EP2841160B1 patent drawingFigure 1b
  • EP2841160B1 patent drawingFigure 2~3

AI summary

The present invention is related to an apparatus and method for hadron beam verification. The apparatus allows to verify a number of different characteristics in a brief time span. The apparatus comprises at least one main degrader element and associated therewith a multiple thickness degrader element. The latter may comprise a number of patches of beam degrading material, the patches having constant but mutually different thicknesses. Alternatively, it may be a wedge-shaped element. By aiming a pencil beam at the various thicknesses, data points can be obtained which allow to make an estimation of the beam range. In addition to this, the apparatus comprises a zone where no degrader material is present, and where a measurement of the spot size can be obtained, without moving or replacing the apparatus.