Gamma Camera CCD Detection Spatial Resolution

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Solution Overview

Problem

Current gamma camera systems face limitations such as temperature and time-dependent photomultiplier tube performance, sensitivity to the Earth's magnetic field, and low spatial resolution due to large detection areas compared to scintillation events, making frequent calibration necessary and image resolution poor.

Innovation Solution

A gamma radiation detecting apparatus utilizing a gamma radiation collimator, scintillation crystal, and an electron multiplying or intensified charge coupled device (CCD) to convert gamma radiation into visible light and then electrical signals, with optical lenses and mirrors to focus and split light, allowing for accurate position determination and high spatial resolution imaging without direct exposure to gamma radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If photomultiplier tubes are used to detect gamma radiation, then gamma radiation detection is achieved, but performance drifts with temperature and time requiring frequent calibration

Engineering Contradiction:

Improvedetection stabilityVSAvoidcalibration frequency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces photomultiplier tubes with a charge-coupled device (CCD) that has no moving parts and is not sensitive to temperature or magnetic field variations. The CCD directly converts gamma-ray interactions into electrical signals without the mechanical and environmental sensitivities of PMT-based systems, eliminating the need for frequent calibration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Area of stationary object

If photomultiplier tubes with large detection area are used, then gamma radiation detection coverage is improved, but spatial resolution deteriorates

Engineering Contradiction:

Improvedetection areaVSAvoidspatial resolution

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent divides the detection area into multiple discrete photodetector elements arranged in a matrix. Each element independently detects gamma-ray interactions at its position, allowing the system to maintain large overall detection coverage while achieving high spatial resolution through the segmented pixel structure. The position of gamma interactions is determined by analyzing which pixels detect signals.

Inventive Principle:

Principle #1Segmentation

3Productivity

If scintillation crystal is directly optically coupled to photomultiplier tubes, then gamma radiation detection efficiency is improved, but crystal exchange becomes difficult

Engineering Contradiction:

Improvedetection efficiencyVSAvoidcrystal exchange ease

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent extracts the optical coupling requirement from the detection system by placing the CCD directly against the scintillation crystal without requiring precise optical alignment. The CCD's direct electrical contact with the crystal allows for easy crystal replacement while maintaining detection efficiency, as the electrical signal transmission does not depend on optical path alignment.

Inventive Principle:

Principle #2Taking out (Extraction)

4Reliability

If charge coupled device is directly exposed to gamma radiation, then gamma radiation detection is achieved, but device damage occurs

Engineering Contradiction:

Improvedetection capabilityVSAvoidgamma radiation exposure

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a scintillation crystal as an intermediary converter between gamma radiation and the CCD. The crystal converts gamma-ray energy into visible light, which then triggers the CCD's photodetector elements. This intermediary conversion protects the CCD from direct gamma radiation exposure while maintaining detection capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 accurate determination of gamma radiation interaction positions and easy scintillation crystal exchange, achieving higher spatial resolution and reducing the need for frequent calibration.

Implementation Method 1

a scintillation crystal which receives the gamma radiation from the gamma radiation collimator and converts the gamma radiation into visible light

Methodology Applied

Scientific EffectScintillation: Scintillation

Implementation Method 2

a charge coupled device which receives the visible light from the scintillation crystal and converts the visible light into an electrical charge

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS8735837B2Gamma camera system

Publication Date: 2014.05.27 IDOINE JOHN D

AI summary

A gamma radiation detecting apparatus includes a gamma radiation collimator, a scintillation crystal, a charge coupled device, and an electronic device. The collimator receives and collimates gamma radiation. The scintillation crystal receives the gamma radiation from the gamma radiation collimator and converts the gamma radiation into visible light. The charge coupled device receives the visible light from the scintillation crystal and converts the visible light into an electrical charge. The electronic device converts the electrical charge into a digital image.