Solid-State Dose Calibration via Photon Spectroscopy

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Solution Overview

Problem

Current dose calibrators for functional imaging, such as PET and SPECT, face inaccuracies due to non-linear conversion of emission counts to activity levels and are limited in spectroscopic performance, particularly when measuring single sources or cocktails of sources.

Innovation Solution

A solid-state dose calibration system that uses one or more solid-state detectors to capture images of radiation sources, automatically adapting system parameters to measure a broad range of photon energies and source activity levels, thereby eliminating the need for manual identification of sources and pre-loading look-up tables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If standard benchtop dose calibrators use ionization chambers with pre-loaded look-up tables for dose calibration, then the device complexity is reduced and ease of operation is improved, but measurement precision deteriorates due to non-linear conversion and limited spectroscopic performance

Engineering Contradiction:
Improvedose calibration accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical ionization chamber system with a solid-state detector system. The solid-state detector directly measures photon energy through electronic signals, eliminating the need for mechanical ionization processes and pre-loaded look-up tables. This substitution improves measurement precision through better spectroscopic performance while managing device complexity through integrated electronics.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental measurement parameter from ionization counts (non-linear) to photon energy spectroscopy (linear). By measuring the energy spectrum of emitted photons and using photopeak identification, the system achieves linear relationship between measured counts and activity, improving dose calibration accuracy without requiring complex non-linear correction tables.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If dose calibrators use pre-loaded look-up tables with predefined isotope settings, then ease of operation is improved and device complexity is reduced, but adaptability deteriorates when measuring cocktails or contaminated sources

Engineering Contradiction:
Improvecapability to measure different radiotracer typesVSAvoiduser operation simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The solid-state detector system performs self-identification of radiotracer isotopes by automatically analyzing the energy spectrum of emitted photons. The system independently determines photopeak energies and identifies isotopes without requiring user input or pre-selection, enabling measurement of any radiotracer type including cocktails and contaminated sources while maintaining ease of operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The solid-state detector system provides universal measurement capability for all radiotracer types through its energy spectroscopy function. A single detector can measure pure isotopes, cocktail mixtures, and contaminated sources by identifying characteristic photopeak energies, eliminating the need for multiple specialized measurement modes or pre-loaded isotope tables.

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

3Measurement precision

If cross-calibration techniques are used to mitigate dose calibrator deficiencies, then measurement precision is improved, but device complexity increases due to specialized collimators and calibration sources

Engineering Contradiction:
Improvedose calibration accuracyVSAvoidrequirement for specialized collimators and calibration sources
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical collimators and external calibration sources with a solid-state detector system that inherently provides spectroscopic measurement capability. The detector's electronic energy discrimination eliminates the need for physical collimation and complex calibration procedures, achieving high measurement precision through direct energy measurement rather than geometric constraints.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 achieves accurate and rapid dose calibration with improved spectroscopic performance, capable of detecting a wide range of photon energies and source activities, and reduces the need for cross-calibration procedures and specialized collimators.

Implementation Method 1

one or more solid-state detectors capture one or more images based on emissions received from the one or more radiation sources

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP4085844B1Solid-state dose calibration system
Publication Date: 2025.04.16 SIEMENS MEDICAL SOLUTIONS USA INC
  • EP4085844B1 patent drawingFigure 1
  • EP4085844B1 patent drawingFigure 2
  • EP4085844B1 patent drawingFigure 3a~3b

AI summary

Systems and methods for dose calibration. A dose calibrator may include one or more radiation sources, one or more solid-state detectors and one or more plates positioned between the one or more radiation sources and the one or more solid-state detectors. The one or more solid-state detectors capture one or more images based on emissions received from the one or more radiation sources through the one or more plates for estimating activity of the one or more radiation sources.