3D SPECT Detector Direction Estimation Without Heavy Shielding

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Solution Overview

Problem

Existing SPECT systems rely on shielding to prevent interference from undesired radiation sources, which adds cost, weight, and bulk, and may block desired signals when the source location is unknown or not mechanically linked to the detector gantry.

Innovation Solution

A 3D spectroscopic detector is used to localize the point of interaction and determine the direction of radioactive emissions without shielding, utilizing different thickness profiles or material types on detector sides to distinguish desired from undesired signals, allowing for directional estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If shielding is used to block radiation from undesired sources, then interference from undesired radiation sources is prevented, but cost, weight, and bulk increase

Engineering Contradiction:
Improveradiation interferenceVSAvoidshielding weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of stationary object

Solution Approach 1:

The patent extracts the shielding component entirely from the system, replacing it with a computational approach that uses the detector's inherent depth-resolution capability to distinguish desired from undesired radiation sources, thereby eliminating the weight penalty of physical shielding

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical shielding system with an information-processing system that uses depth information from detected emissions to computationally filter radiation sources, substituting physical blocking with digital discrimination

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

2Object-affected harmful factors

If shielding is used to block radiation from undesired sources, then interference from undesired radiation sources is prevented, but cost increases

Engineering Contradiction:
Improveradiation interferenceVSAvoidsystem cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent removes the shielding component from the system design, replacing expensive physical shielding materials with a computational algorithm that leverages the detector's depth-resolution capability to achieve source discrimination without additional material costs

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-affected harmful factors

If shielding is used to block radiation from undesired sources, then interference from undesired radiation sources is prevented, but device size increases

Engineering Contradiction:
Improveradiation interferenceVSAvoiddetector volume
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The patent extracts and removes the shielding structure from the detector assembly, replacing it with software-based source discrimination that uses depth information, thereby reducing the overall device volume without compromising the ability to reject undesired radiation

Inventive Principle:
Principle #2Taking out (Extraction)

4Object-affected harmful factors

If shielding is used to block radiation, then signal from undesired sources is prevented, but desired signal may be blocked when source location is unknown

Engineering Contradiction:
Improveundesired radiation signalVSAvoiddesired signal detection
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent implements a dynamic, adaptive system that uses depth information to identify and track the location of radiation sources in real-time, allowing the system to dynamically adjust which signals are accepted or rejected based on the current source position, thereby preventing desired signal loss

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs feedback through depth-resolution measurements that provide information about emission origin, allowing the system to continuously refine its understanding of source location and adjust signal acceptance criteria accordingly, ensuring desired signals are not erroneously blocked

Inventive Principle:
Principle #23Feedback

5Object-affected harmful factors

If shielding is used to block radiation, then interference is reduced, but device complexity increases

Engineering Contradiction:
Improveradiation interferenceVSAvoidshielding design complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent removes the complex shielding design from the system, replacing it with a computational algorithm that processes depth information from the detector, thereby reducing mechanical design complexity while maintaining or improving interference rejection capability

Inventive Principle:
Principle #2Taking out (Extraction)

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 approach eliminates the need for shielding, reducing cost, weight, and size while accurately determining the direction of radioactive sources, enabling efficient localization and imaging without blocking desired signals.

Implementation Method 1

A 3D spectroscopic detector may be used to detect a direction of a source of radiation

Methodology Applied
Scientific EffectGamma ray detection: Photoelectric Effect

Implementation Method 2

The SPECT system uses a spectroscopic, low spatial resolution detector to localize the Point-of-(first) Interaction (POI) within the detector sensor material in 3D

Methodology Applied
Scientific EffectDepth of interaction detection: Compton Scattering

Data Source

PatentEP4707872A1Directional estimation for radioactive source localization in single photon emission computed tomography
Publication Date: 2026.03.11 SIEMENS MEDICAL SOLUTIONS USA INC
  • EP4707872A1 patent drawingFigure 1~2
  • EP4707872A1 patent drawingFigure 3~4
  • EP4707872A1 patent drawingFigure 5

AI summary

For radioactive source localization, the SPECT system (100) uses a spectroscopic, low spatial resolution detector (108) to localize the Point-of-(first) Interaction (POI) within the detector (108) sensor material in 3D ("3D detector" or "3D spectroscopic detector"), which in turn can be used to estimate (510) the general direction of the source of emissions. By detecting (500) the depth of the 3D POI, and emissions over the specified energy range, a processor (120) may determine (510) a direction towards the source. No shielding is needed as detected emissions from other directions may be discarded. Different shielding (230) may be used to assist in directionality determination, such as different thickness profiles or material type by a side of the detector (108), allowing directional determination by intensity.