Nuclear Medicine Image Contrast via Region-Specific LUT Normalization

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Solution Overview

Problem

Nuclear medicine images generated using a single look-up table (LUT) often result in poor contrast for regions with low radioisotope concentration, such as the liver, making it difficult to diagnose and detect lesions effectively.

Innovation Solution

The nuclear medicine diagnostic apparatus includes a region of interest (ROI) setting unit and a normalization unit that adjusts the association between count values and pixel values based on the distribution of count values within the ROI, using various normalization methods to enhance contrast and visibility, allowing for the use of the same LUT for both specified and partial imaging regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a predetermined LUT is used for whole body photographing, then high RI concentration regions have high brightness, but low RI concentration regions become poor in contrast

Engineering Contradiction:
Improvebrightness of high RI concentration regionsVSAvoidcontrast of low RI concentration regions
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The imaging region is divided into a specified region and a partial region, with different LUTs applied to each. The specified region uses a first LUT optimized for high RI concentration areas, while the partial region uses a second LUT optimized for low RI concentration areas, thereby resolving the contrast problem in low concentration regions without sacrificing brightness in high concentration regions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different quality characteristics are applied to different parts of the image through region-specific LUTs. The specified region receives a LUT configuration suited for high brightness display, while the partial region receives a LUT configuration optimized for contrast enhancement in low concentration areas, making each region's display characteristics match its diagnostic requirements.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If different LUTs are used for specified and partial imaging regions, then contrast in partial regions is improved, but device complexity increases

Engineering Contradiction:
Improvecontrast of partial imaging regionsVSAvoidcomplexity of LUT management
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses a single display device that can dynamically apply different LUTs to different regions based on the imaging type. The control unit automatically selects and applies the appropriate LUT configuration (first LUT for specified region, second LUT for partial region) without requiring separate display devices or complex manual configuration, thereby reducing operational complexity while maintaining region-specific optimization.

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

3Measurement precision

If normalization is applied to enhance visibility of low concentration regions, then detection rate of lesions is improved, but processing time increases

Engineering Contradiction:
Improvedetection rate of lesionsVSAvoidimage processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system pre-calculates and stores multiple LUTs optimized for different regions and concentration levels. During image processing, the control unit simply selects and applies the appropriate pre-prepared LUT based on the imaging type, avoiding the need for time-consuming real-time normalization calculations while still achieving enhanced visibility and improved lesion detection rates.

Inventive Principle:
Principle #10Preliminary action

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 enhances the visibility of regions with low radioisotope concentration, improving the detection rate of lesions and reducing inter- and intra-observer errors, thereby supporting more accurate and efficient diagnostics.

Implementation Method 1

detect a gamma ray emitted from an RI distributed in a living body with a gamma ray detector provided outside the living body

Methodology Applied
Scientific EffectGamma ray emission: Radioactive Decay

Data Source

PatentUS10517559B2Nuclear medicine diagnostic apparatus, diagnostic imaging apparatus, and image processing method
Publication Date: 2019.12.31 CANON MEDICAL SYST CORP
  • US10517559B2 patent drawing
  • US10517559B2 patent drawing
  • US10517559B2 patent drawing

AI summary

According to one embodiment, a nuclear medicine diagnostic apparatus includes a counting unit, a region of interest setting unit, a normalization unit, and an image generation unit. The counting unit counts radiation emitted from radioisotopes in an imaging region of an object. The ROI setting unit sets a region of interest (ROI) in the imaging region. The normalization unit determines association between count values and pixel values of display pixels for the ROI in accordance with a distribution of the count values of the display pixels corresponding to the ROI. The image generation unit generates an image of the ROI based on the association between the count values and the pixel values for the ROI.