Acoustic Array Detector Scanning for Uniform Photoacoustic Resolution

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Solution Overview

Problem

Photoacoustic tomography systems face variations in resolution depending on location due to the placement of acoustic detection elements, leading to non-uniform imaging quality, especially when transitioning from planar to spherical surfaces.

Innovation Solution

The apparatus addresses this by moving at least one of the subject or the acoustic array detector with a plurality of acoustic detection elements, allowing for the adjustment of the relative position to achieve uniform resolution across the imaging area, utilizing a scanning method that aligns with the gradient of resolution to ensure consistent image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If acoustic detection elements are placed on a spherical surface, then lateral resolution is improved to be equal to depth resolution, but resolution varies with location (highest at center, decreasing toward periphery)

Engineering Contradiction:
Improvelateral resolutionVSAvoiduniformity of resolution
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent applies the dynamics principle by making the acoustic array detector movable rather than fixed. The detector can be positioned and repositioned at different locations around the subject, allowing the high-resolution central region to be applied to different imaging areas. This dynamic positioning capability resolves the contradiction by enabling uniform resolution across the entire imaging field through multiple measurements from different detector positions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent transitions from a single static detector position to multiple positions in three-dimensional space. By adding the spatial dimension of detector movement, the system can capture data from multiple angles and positions, effectively transforming the resolution uniformity problem from a two-dimensional surface issue to a three-dimensional sampling problem that can be solved through spatial diversification of measurement points.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If acoustic detection elements are placed on a planar surface, then device complexity is reduced, but depth resolution is limited by detection element frequency capabilities

Engineering Contradiction:
Improvedetector placement complexityVSAvoiddepth resolution
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent makes the detector arrangement dynamic rather than static. Instead of requiring a complex fixed spherical arrangement, the system uses a simpler detector that can be moved to multiple positions. This dynamic approach achieves the resolution benefits of spherical placement while maintaining the simplicity of planar or linear detector configurations during actual operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs periodic action by repeatedly positioning the detector at different locations around the subject. The detector is moved to multiple predetermined positions, and measurements are taken at each position in sequence. This periodic repositioning and measurement cycle allows the system to accumulate data equivalent to a full spherical arrangement while using a simpler detector configuration at any given moment.

Inventive Principle:
Principle #19Periodic action

3Area of stationary object

If the hemisphere is rotated during light irradiation and acoustic wave reception, then imaging coverage is improved, but measurement time increases

Engineering Contradiction:
Improveimaging coverageVSAvoidmeasurement time
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

The patent applies dynamics by making either the subject or the acoustic array detector movable. Instead of rotating the entire hemisphere during measurement, the system uses a simpler movable component (either the subject holder or the detector array) to achieve the necessary spatial coverage. This selective movement reduces the complexity and time of the measurement process while maintaining comprehensive imaging coverage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses preliminary action by pre-positioning the acoustic detection elements at multiple locations before measurement begins. The detector is placed at predetermined positions around the subject, and all necessary measurements are taken at these fixed positions. This eliminates the need for continuous rotation or movement during the measurement process, thereby reducing measurement time while maintaining complete imaging coverage.

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 reduces variations in resolution, achieving higher and more uniform image resolution across the entire imaging area, enhancing the detection efficiency and accuracy of functional information within the subject.

Implementation Method 1

using the photoacoustic effect in which acoustic waves (typically ultrasonic waves) are generated by applying pulsed light generated from a light source to a subject and absorbing the light that has propagated and diffused in the subject

Methodology Applied
Scientific EffectPhotoacoustic effect: Photoacoustic Effect

Data Source

PatentEP2672896B1Acoustic-wave acquisition apparatus
Publication Date: 2022.04.06 CANON KK
  • EP2672896B1 patent drawingFigure 1
  • EP2672896B1 patent drawingFigure 2~3A
  • EP2672896B1 patent drawingFigure 3B~3D

AI summary

With a detector in which detection elements are placed in a spherical shape, a uniform resolution area is narrow. An acoustic-wave acquisition apparatus of the present invention is equipped with a detector including a plurality of detection elements that receive acoustic waves from a subject, the receiving surfaces of at least some of the detection elements being at different angles. The apparatus includes a scanning unit configured to move at least one of the subject and the detector to change the relative position of the subject and a highest-resolution area determined depending on the placement of the detection elements.