Suite of 3D test objects for performance assessment of hybrid photoacoustic-ultrasound breast imaging systems

Abstract

Significance: During the development and early testing phases of new photoacoustic (PA) breast imaging systems, several choices need to be made in aspects of system design and measurement sequences. Decision-making can be complex for state-of-the-art systems such as 3D hybrid photoacoustic-ultrasound (PA-US) breast imagers intended for multispectral quantitative imaging. These systems have a large set of design choices and system settings that affect imaging performance in different ways and often require trade-offs. Decisions have to be made carefully as they can strongly influence the imaging performance.Aim: A systematic approach to assess the influence of various choices on the imaging performance in carefully controlled laboratory situations is crucial before starting with human studies. Test objects and phantoms are used for first imaging studies, but most reported structures have a 2D geometry and are not suitable to assess all the image quality characteristics (IQCs) of 3D hybrid PA-US systems.Approach: Our work introduces a suite of five test objects designed for hybrid PA-US systems with a 3D detection aperture. We present the test object designs and production protocols and explain how they can be used to study various performance measures. To demonstrate the utility of the developed objects, measurements are made with an existing tomographic PA system.Results: Two test objects were developed for measurements of the US detectors' impulse responses and light distribution on the breast surface. Three others were developed to assess image quality and quantitative accuracy of the PA and US modes. Three of the five objects were imaged to demonstrate their use. Conclusions:The developed test objects allow one to study influences of various choices in design and system settings. With this, IQCs can be assessed as a function of measurement sequence settings for the PA and US modes in a controlled way. Systematic studies and measurements using these objects will help to optimize various system settings and measurement protocols in laboratory situations before embarking on human studies.

A review of a strategic roadmapping exercise to advance clinical translation of photoacoustic imaging: From current barriers to future adoption

“…In addition, most current phantoms described for testing PAI oximetry performance require complex, custom blood flow circuits [54] , [55] , [56] that may not be widely accessible in different laboratories. Simpler phantom designs may be well suited for foundational performance testing and quality management systems [57] , but may be less useful for studying complex, application-specific imaging scenarios. Phantoms that are prepared by research groups are therefore often unable to fulfil the general design criteria for performance assessment in biophotonics [37] .…”

Photoacoustic imaging plus X: a review

“…Breast imaging is one of the clinical applications of PA imaging, and there have been numerous studies on breast PA imaging, 124 including the development of PA-US dual-modal systems. Zheng et al.…”

A hybrid multispectral photoacoustic-ultrasound breast imager: from the lab towards the clinic

“…See Figure 6.3.D for the radial profile of the eight different cups and a description of the production protocol of these cups can be found in Ref. Chapter 3 [284]. The cups were filled with water and imaged using illumination with 755 nm light, data being acquired with 201 bowl positions and 10 averages per position.…”

“…The object has the shape of the largest breast supporting cup and the targets are distributed throughout its volume. A detailed description of the test object can be found in Section 3.3.1 of this dissertation [284]. The test object was placed in a size eight breast-supporting cup in the imaging bowl.…”

“…TOFs for determining the sound speeds of the materials were obtained from the peak amplitude of the signals transmitted through the PAG or transmitted and then reflected to the liquids. More information about the SOS object and the characterization measurements can be found Chapter 3 [284]. A measurement sequence with 755 nm excitation, 101 bowl positions and 57 averages was selected for the PAMMOTH measurement on the object.…”